Science & tech flashcards
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129 decks
- Cell Membranes and TransportRecall cards on the structure and function of plasma membranes and membrane transport.
- MetabolismRecall cards on bioenergetics, thermodynamics, ATP, and enzymes.
- Cellular RespirationRecall cards on how cells extract energy from glucose: redox and electron carriers, glycolysis, the citric acid cycle, oxidative phosphorylation, fermentation, and regulation.
- PhotosynthesisRecall cards on how photoautotrophs capture light energy and build sugars: the overview and chemical equation, leaf and chloroplast structure, the light-dependent reactions (pigments, photosystems, water-splitting, chemiosmosis), and the Calvin cycle.
- Cell CommunicationRecall cards on how cells signal to one another and respond: types of chemical signaling (paracrine, endocrine, autocrine, direct), internal and cell-surface receptors, signal transduction and second messengers, the cellular response, and signaling in single-celled organisms.
- Cell ReproductionRecall cards on how cells reproduce: genomes and chromosome structure, DNA compaction, the cell cycle (interphase and mitosis), cytokinesis in animals and plants, cell-cycle checkpoints and their positive and negative regulators, cancer, and prokaryotic binary fission.
- Meiosis and Sexual ReproductionRecall cards on meiosis and sexual reproduction: haploid and diploid cells, the two meiotic divisions (meiosis I and II), synapsis, crossing over and chiasmata, independent assortment, how meiosis differs from mitosis, why sexual reproduction persists, and the diploid-dominant, haploid-dominant, and alternation-of-generations life cycles.
- Mendel's Experiments and HeredityRecall cards on Mendelian genetics: Gregor Mendel's pea experiments, true-breeding lines, the P/F1/F2 generations, dominant and recessive traits, genotype and phenotype, alleles and loci, homozygous and heterozygous, the 3:1 and 1:2:1 ratios, Punnett squares and test crosses, incomplete dominance, codominance, multiple alleles, lethal and X-linked alleles, the laws of dominance, segregation, and independent assortment, dihybrid 9:3:3:1 crosses, linkage and recombination, and epistasis.
- Modern Understanding of InheritanceRecall cards on the chromosomal basis of heredity: the chromosomal theory of inheritance (Boveri, Sutton, Carothers, Morgan), genetic linkage, crossing over and chiasmata, parental versus recombinant offspring, recombination frequency, genetic maps and centimorgans, three-point crosses, karyotypes and karyograms, nondisjunction, aneuploidy (monosomy and trisomy including Down syndrome), sex-chromosome variations (triplo-X, Klinefelter, Turner) and X inactivation, polyploidy, and chromosome structure changes (duplications, deletions, inversions, translocations).
- DNA Structure and FunctionRecall cards on DNA structure and function: the historical experiments identifying DNA as the genetic material (Miescher, Griffith, Avery-MacLeod-McCarty, Hershey-Chase, Chargaff), the structure of the double helix (nucleotides, purines and pyrimidines, base pairing, antiparallel strands, phosphodiester bonds, helix dimensions), DNA packaging (supercoiling, nucleosomes, heterochromatin and euchromatin), sequencing and gel electrophoresis, the semi-conservative model and the Meselson-Stahl experiment, DNA replication in prokaryotes and eukaryotes (origins, forks, helicase, primase, polymerases, leading and lagging strands, Okazaki fragments, telomeres and telomerase), and DNA repair and mutation types.
- Genes and ProteinsRecall cards on how genes are expressed as proteins: the genetic code (the central dogma, triplet codons, degeneracy, start and stop codons, reading frames and frameshifts, the Crick-Brenner experiment, the near-universal code); prokaryotic transcription (a single RNA polymerase, sigma factor and the holoenzyme, template versus coding strand, the -10 and -35 promoter consensus sequences, rho-dependent and intrinsic termination, polycistronic mRNA); eukaryotic transcription (three RNA polymerases, the TATA box and transcription factors, nucleosomes and the FACT complex); RNA processing (exons and introns, the 5' cap, the poly-A tail, splicing by spliceosomes, UTRs, tRNA anticodons); and translation (ribosome subunits, tRNA charging by aminoacyl-tRNA synthetases, the A, P, and E sites, prokaryotic and eukaryotic initiation, the Shine-Dalgarno sequence and Kozak's rules, peptidyl transferase, termination by release factors, signal sequences and chaperones).
- Gene ExpressionRecall cards on how cells regulate gene expression: the levels of regulation (why cells regulate, prokaryotic versus eukaryotic control, the five eukaryotic stages); prokaryotic operons (the trp and lac operons, repressors, activators and inducers, corepressors, cAMP and the catabolite activator protein, inducible versus repressible control); eukaryotic epigenetic regulation (nucleosomes, chromatin remodeling, histone modification, DNA methylation and CpG islands, imprinting); eukaryotic transcriptional control (general and specific transcription factors, the TATA, CAAT and GC boxes, enhancers and DNA bending); post-transcriptional control (alternative splicing, mRNA stability and UTRs, microRNAs, Dicer and RISC); translational and post-translational control (the eIF-2 switch, cap-poly-A looping, protein modification, ubiquitin and the proteasome); and cancer as a disease of altered gene expression (tumor-suppressor genes, p53, proto-oncogenes and oncogenes, cancer epigenetics, and gene-expression-targeted therapies).
- Biotechnology and GenomicsRecall cards on biotechnology and genomics: the basic techniques (nucleic-acid isolation, gel electrophoresis, PCR and RT-PCR, Southern and Northern blotting, probes); molecular cloning (plasmid vectors, restriction endonucleases and sticky ends, DNA ligase, recombinant and chimeric DNA, the multiple cloning site); applications (recombinant insulin and growth hormone, reproductive and therapeutic cloning, somatic cell nuclear transfer and Dolly, genetic engineering, GMOs and transgenic organisms, gene therapy, Agrobacterium and the Ti plasmid, Bt crops, the Flavr Savr tomato, reverse genetics and gene targeting); mapping genomes (genetic versus physical maps, linkage analysis, RFLP, SNP and VNTR markers, cytogenetic, radiation-hybrid and sequence mapping, STSs and ESTs); whole-genome sequencing (Sanger chain termination and ddNTPs, shotgun and pairwise-end sequencing, next-generation sequencing, annotation and microarrays); and applied genomics and proteomics (pharmacogenomics, metagenomics, mitochondrial DNA, the proteome versus the genome, biomarkers and protein signatures, metabolomics and systems biology).
- Evolution and the Origin of SpeciesRecall cards on evolution and speciation: understanding evolution (natural selection and its three conditions, descent with modification, Darwin and Wallace, the Galapagos finches and the Grants' study, sources of genetic variation, adaptation, divergent versus convergent evolution); the evidence for evolution (fossil record, homologous and analogous and vestigial structures, embryology, biogeography and Pangaea, molecular and genetic evidence, gene duplication); common misconceptions (theory in science, evolution acting on populations, origin of life, goal-direction, antibiotic resistance); the formation of new species (the biological species concept, speciation, reproductive isolation, allopatric versus sympatric speciation, dispersal and vicariance, adaptive radiation, auto- and allopolyploidy, prezygotic and postzygotic barriers); and reconnection and speciation rates (hybrid zones, reinforcement, fusion, and stability, hybrid fitness, gradualism versus punctuated equilibrium).
- The Evolution of PopulationsRecall cards on population genetics and adaptive evolution: population evolution (population genetics, the modern synthesis, microevolution versus macroevolution, populations evolve while individuals do not, allele and genotype frequencies, the gene pool, the Hardy-Weinberg principle and its equations and equilibrium assumptions); population genetics forces (genetic and phenotypic variation, heritability, genetic drift, the bottleneck and founder effects, gene flow, mutation, nonrandom and assortative mating, inbreeding and inbreeding depression, clines and geographic variation); and adaptive evolution (fitness and relative fitness, stabilizing, directional, and diversifying selection, frequency-dependent selection, sexual dimorphism and sexual selection, the handicap principle and good genes hypothesis, and the constraints that keep selection from producing a perfect organism).
- Phylogenies and the History of LifeRecall cards on phylogeny and the history of life: organizing life on Earth (phylogeny and phylogenetic trees, taxonomy and systematics, the Linnaean hierarchy, the three domains, binomial nomenclature, and the parts of a tree, including rooted and unrooted trees, nodes, basal and sister taxa, polytomies, and what branch length does and does not mean); determining evolutionary relationships (homologous versus analogous structures and homoplasies, molecular systematics, cladistics and clades, shared ancestral versus shared derived characters, and maximum parsimony); and perspectives on the phylogenetic tree (horizontal gene transfer and its mechanisms, gene transfer agents, HGT in prokaryotes and eukaryotes, and alternative models of early evolution, including the web-of-life, ring-of-life, endosymbiont, and genome-fusion models).
- VirusesRecall cards on viruses: their evolution, morphology, and classification (how viruses were discovered, their sizes and imaging, hypotheses for their origins, virion structure and capsid types, attachment and receptors, DNA versus RNA genomes, and the Baltimore classification groups); virus infections and hosts (the replication cycle, bacteriophage lytic and lysogenic cycles, animal and retrovirus replication, latency, viral release, acute, chronic, and asymptomatic infections, plant viruses and their transmission, and oncogenic viruses); prevention and treatment (vaccines, antiviral drugs, HIV therapy, and viruses and phages used in medicine); and other acellular entities (prions and viroids).
- Prokaryotes: Bacteria and ArchaeaRecall cards on prokaryotes: their diversity (prokaryotes as Earth's first cells, microbial mats and stromatolites, the oxygenation of the atmosphere, extremophiles, culturing and biofilms); the structure of Bacteria and Archaea (cell shapes, walls and membranes, the nucleoid and plasmids, reproduction and gene transfer, and the molecular differences between the two domains); prokaryotic metabolism (macronutrients, nutritional categories, and the nitrogen and carbon cycles); and bacterial diseases in humans (epidemics and pandemics, plague, typhoid, Lyme disease, foodborne illness, biofilms, and antibiotic resistance).
- ProtistsRecall cards on protists: eukaryotic origins (the defining nucleus, the single eukaryotic ancestor, endosymbiotic theory, and the bacterial origins of mitochondria and plastids by primary and secondary endosymbiosis); the general characteristics of protists (habitats, nutrition, motility, cell coverings, and reproduction); the major groups across the six eukaryotic supergroups (Excavata, Chromalveolata, Archaeplastida, Rhizaria, Amoebozoa, and Opisthokonta, with their representative diplomonads, parabasalids, euglenozoans, dinoflagellates, apicomplexans, ciliates, diatoms, algae, foraminiferans, radiolarians, amoebas, slime molds, and choanoflagellates); and the ecology of protists (primary production, symbioses with coral, and human diseases such as malaria, sleeping sickness, Chagas disease, and potato blight).
- FungiRecall cards on fungi: their defining characteristics (chitin cell walls, ergosterol membranes, hyphae, septa, mycelium, heterotrophic external digestion, and asexual and sexual reproduction through plasmogamy, karyogamy, and meiosis); the five phyla (Chytridiomycota, Zygomycota, Ascomycota, Basidiomycota, and Glomeromycota) plus the former imperfect fungi; the ecology of fungi (decomposition, mycorrhizae, lichens, endophytes, and symbioses with ants); fungal parasites and pathogens (ergot, mycoses, dermatophytes, and diseases of humans, bats, and frogs); and the importance of fungi in human life (food, fermentation, antibiotics, immunosuppressants, model organisms, and mycorrhizal support of plant life).
- Seedless PlantsRecall cards on seedless plants: the origin of land plants within the Archaeplastida and the four adaptations to land (alternation of generations, apical meristems, waxy cuticle, and lignin); alternation of generations, sporangia, homospory and heterospory, sporopollenin, gametangia, and vascular tissue; the green algae (chlorophytes and charophytes) as precursors of land plants; the bryophytes (liverworts, hornworts, and mosses) with their dominant gametophytes and flagellated sperm; and the seedless vascular plants (lycophytes and the monilophytes: whisk ferns, horsetails, and ferns) with their dominant sporophytes, xylem and phloem, sporophylls and strobili, fronds and sori, and their ecological and human uses.
- Seed PlantsRecall cards on seed plants: the evolutionary advantages of pollen and seeds, the reduction of the gametophyte, and the fossil timeline from progymnosperms through gymnosperm dominance to the rise of the angiosperms; the gymnosperms (conifers, cycads, ginkgo, and gnetophytes) with their naked seeds, cones, tracheid wood, and wind-and-insect pollination; the angiosperms (flower structure, the carpel and stamen, double fertilization and endosperm, fruit, and the split among basal angiosperms, monocots, and eudicots); and the roles of seed plants as food, fiber, fuel, and medicine, their coevolution with pollinators and herbivores, and their part in stabilizing ecosystems.
- Introduction to Animal DiversityRecall cards introducing the animal kingdom: the shared features of animals (heterotrophy, tissues, no cell walls, the diplontic life cycle, and the five clades from Parazoa to Bilateria); sexual, asexual, and parthenogenetic reproduction; embryonic development from cleavage through gastrulation, the germ layers, metamorphosis, and the Hox genes that pattern the body plan; the features used to classify animals (symmetry, germ layers, the coelom, and protostome versus deuterostome development); animal phylogeny (Eumetazoa, Radiata and Bilateria, Ecdysozoa and Lophotrochozoa, and choanoflagellate ancestry); and the evolutionary history of animals across the Ediacaran, the Cambrian explosion, and the later mass extinctions.
- InvertebratesRecall cards on the major invertebrate phyla: the tissue-less sponges (Porifera) with their spongocoel, choanocytes, and spicules; the diploblastic Cnidaria with their cnidocytes, polyp and medusa forms, and coral reefs; the lophotrochozoan flatworms, rotifers, and nemerteans; the mollusks and the segmented annelids; the molting ecdysozoan nematodes and tardigrades; the arthropods with their exoskeleton, tagmata, and subphyla from chelicerates to insects; and the invertebrate deuterostomes, the echinoderms with their water vascular system and the invertebrate chordates.
- VertebratesRecall cards on the vertebrates and their chordate kin: the five chordate characteristics and the invertebrate lancelets and tunicates; the jawless hagfishes and lampreys and the jawed cartilaginous and bony fishes; the amphibians with their moist skin and metamorphosis; the amniote reptiles, from the amniotic egg and temporal fenestrae to crocodilians, tuataras, squamates, and turtles; the endothermic birds with their feathers, flight muscles, and air-sac lungs; the mammals with hair, mammary glands, and the three-boned middle ear across monotremes, marsupials, and eutherians; and the evolution of the primates through monkeys, apes, and the hominin lineage to Homo sapiens.
- Plant Form and PhysiologyRecall cards on plant form and physiology: the shoot and root organ systems; meristematic and permanent tissues and the dermal, vascular, and ground tissue systems; stem anatomy and modifications, primary and secondary growth, wood, and bark; root structure and zones, the endodermis and Casparian strip, and root modifications; leaf anatomy, venation, phyllotaxy, and adaptations; water potential, transpiration and the cohesion-tension theory, and phloem translocation by the pressure-flow model; and plant sensory systems, from phytochrome and photoperiodism to the plant hormones and defenses.
- Soil and Plant NutritionRecall cards on soil and plant nutrition: the essential elements and the nine macronutrients and the micronutrients, their roles and deficiency symptoms, and hydroponics; the composition, particle sizes, and formation factors of soil, humus, and the soil profile horizons; and nutritional adaptations including biological nitrogen fixation, rhizobia and nodules, mycorrhizae, epiphytes, parasitic and saprophytic plants, and insectivorous plants.
- Plant ReproductionRecall cards on plant (angiosperm) reproduction: alternation of generations and flower anatomy (the four whorls, complete vs incomplete, monoecious vs dioecious); development of the male and female gametophytes; pollination (self vs cross, self-incompatibility, and animal, wind, and water pollinators); double fertilization, embryo and seed structure, germination, and fruit types and seed dispersal; and asexual reproduction, vegetative propagation, and plant life spans.
- The Animal Body: Basic Form and FunctionRecall cards on animal form and function: body symmetry and directional terms; the physical constraints of size and shape (drag, gravity, exoskeletons, endoskeletons, diffusion and the surface-area-to-volume ratio); animal bioenergetics (energy storage, metabolic rate, endotherms and ectotherms, torpor); anatomical planes and body cavities; the four primary tissues (epithelial, connective, muscle, and nervous); and homeostasis (set points, negative and positive feedback, acclimatization, and thermoregulation).
- Animal Nutrition and the Digestive SystemRecall cards on animal nutrition and digestion: dietary categories (herbivores, carnivores, omnivores); digestive-system types (gastrovascular cavity, alimentary canal, monogastric, avian, ruminant, and pseudo-ruminant); the vertebrate digestive organs from oral cavity to anus and the accessory organs (liver, pancreas, gallbladder); essential nutrients, the vitamins and minerals with their functions and deficiency diseases; ATP and energy production; the four digestive processes (ingestion, digestion, absorption, elimination) with carbohydrate, protein, and lipid digestion; and neural and hormonal regulation of digestion.
- The Nervous SystemRecall cards on the animal nervous system: neuron structure (soma, dendrites, axon, synapse) and the neuron types; glial cells (astrocytes, microglia, oligodendrocytes, Schwann cells, and others); how neurons communicate through the resting membrane potential, the action potential, and chemical and electrical synapses; synaptic integration and plasticity (summation, LTP, LTD); the central nervous system (meninges, cerebrospinal fluid, the cortex and its lobes, subcortical structures, the brainstem, and the spinal cord); the peripheral nervous system (autonomic sympathetic and parasympathetic divisions and the sensory-somatic division); and nervous system disorders (Alzheimer's, Parkinson's, autism, ADHD, schizophrenia, depression, epilepsy, and stroke).
- Sensory SystemsRecall cards on animal sensory systems: how sensory reception, transduction, and perception work, receptor types and receptive fields, receptor potentials, the labeled-line principle, and Weber's Law; somatosensation (the skin layers and the four somatosensory receptor classes, the tactile mechanoreceptors, proprioceptors, baroreceptors, thermoreception, nociception, and two-point discrimination); taste and smell (the five tastes, papillae and taste buds, salt and sour versus sweet, bitter, and umami transduction, the olfactory epithelium and bulb, combinatorial odor coding, and pheromones); hearing and vestibular sensation (sound as pressure waves, the outer, middle, and inner ear, the cochlea and basilar membrane, place theory, and the utricle, saccule, and semicircular canals); and vision (light and the eye, refractive errors, rods and cones, rhodopsin phototransduction, trichromatic cones, retinal circuitry and lateral inhibition, and the pathway to the visual cortex).
- The Endocrine SystemRecall cards on the animal endocrine system: hormones as chemical signals and their three chemical classes (lipid-derived steroids, amino acid-derived hormones, and peptide hormones) with their solubility, transport, and half-lives; how hormones work (receptor up- and down-regulation, intracellular versus cell-surface receptors, and the first- and second-messenger G-protein, adenylyl cyclase, cAMP, and protein-kinase cascade with amplification); regulation of body processes (ADH and aquaporins, aldosterone and the renin-angiotensin system, the reproductive axis, insulin and glucagon and diabetes, the thyroid hormones and calcium regulation, growth hormone, and the short- and long-term stress responses); the humoral, hormonal, and neural stimuli and negative feedback that control hormone release; and the endocrine glands (hypothalamus, pituitary, thyroid, parathyroid, adrenal, pancreas, pineal) plus secondary endocrine organs.
- The Musculoskeletal SystemRecall cards on the animal musculoskeletal system: the three skeletal designs (hydrostatic skeleton, exoskeleton, endoskeleton) and the 206-bone human axial and appendicular skeleton (skull, vertebral column, thoracic cage, girdles, and limbs); bone as a tissue (bone shapes, compact and spongy bone, osteons, the four bone cell types, ossification, growth, remodeling, and fracture repair); the structural and functional classification of joints (fibrous, cartilaginous, and the six synovial joint types) and the body movements they allow; and muscle contraction (the three muscle tissue types, sarcomere and myofilament structure, the sliding filament model, the cross-bridge and ATP cycle, excitation-contraction coupling at the neuromuscular junction, and how muscle tension and whole-muscle force are set).
- The Respiratory SystemRecall cards on the animal respiratory system: systems of gas exchange (why diffusion alone fails as body size grows, and the diversity of respiratory surfaces from skin and gills to insect tracheae and the mammalian airway from nasal cavity to alveoli); gas exchange across respiratory surfaces (partial pressure, the composition of air, and the oxygen and carbon dioxide partial-pressure gradients that drive diffusion in the lungs and tissues); breathing (Boyle's law and the mechanics of inhalation and exhalation, the pleurae, surfactant, lung compliance and resistance, restrictive and obstructive diseases, dead space, and gas exchange in amphibians and birds); and the transport of gases in bodily fluids (hemoglobin and cooperative oxygen binding, the oxygen-hemoglobin dissociation curve and what shifts it, the bicarbonate buffer system and chloride shift that carry carbon dioxide, and carbon monoxide poisoning).
- The Circulatory SystemRecall cards on the animal circulatory system: an overview of circulation (why bulk flow replaces diffusion as body size grows, open versus closed systems, and the evolution of two-, three-, and four-chambered hearts across fish, amphibians, reptiles, birds, and mammals); the components of the blood (plasma, red blood cells and hemoglobin, alternative respiratory pigments, white blood cells, platelets and clotting, serum proteins, and the ABO and Rh blood groups); the mammalian heart and blood vessels (the chambers, valves, wall layers and coronary supply, the cardiac cycle and its conduction system from the SA node to the Purkinje fibers, and the structure of arteries, capillaries, and veins); and blood flow and blood pressure regulation (systolic and diastolic pressure, flow speed and capillary exchange, precapillary sphincters, the lymphatic system, and cardiac output).
- Osmotic Regulation and ExcretionRecall cards on how animals balance water and salts and clear nitrogenous waste: osmoregulation and osmotic balance (osmosis, electrolytes and non-electrolytes, tonicity, the ways concentration is measured, and stenohaline versus euryhaline strategies in fish, osmoconformers, and sharks); the kidneys and osmoregulatory organs (gross kidney anatomy, the nephron and its blood supply, and the three steps of urine formation including the loop of Henle countercurrent system and the juxtaglomerular complex); excretion systems of invertebrates (contractile vacuoles, flame cells, nephridia, and Malpighian tubules); nitrogenous wastes (ammonotelic, ureotelic, and uricotelic animals, the urea cycle, and uric acid, gout, and kidney stones); and the hormonal control of osmoregulation (the renin-angiotensin-aldosterone system, aldosterone, antidiuretic hormone, and atrial natriuretic peptide).
- The Immune SystemRecall cards on how animals defend against pathogens: the innate immune response (physical and chemical barriers, PAMPs and pattern recognition receptors including Toll-like receptors, phagocytes such as macrophages and neutrophils, cytokines, interferons and inflammation, natural killer cells and MHC I recognition, and the complement cascade); the adaptive immune response (cell-mediated versus humoral immunity, antigen-presenting cells and MHC processing, helper and cytotoxic T cells, T cell receptors, B cells and clonal selection, immune tolerance, immunological memory and vaccination, mucosal immunity, and the lymphatic organs); antibodies (their four-chain structure and gene recombination, the five immunoglobulin classes, neutralization, opsonization and complement fixation, affinity and avidity, cross reactivity, and radioimmunoassay); and disruptions of immunity (immunodeficiency, immediate and delayed hypersensitivity and allergy, autoimmunity, and pathogen evasion strategies).
- Animal Reproduction and DevelopmentRecall cards on how animals reproduce and develop: asexual modes (fission, budding, fragmentation, and parthenogenesis) versus sexual reproduction, hermaphroditism, and the genetic, chromosomal, and environmental systems of sex determination; fertilization strategies (external broadcast spawning versus internal fertilization, and oviparity, ovoviviparity, and viviparity); human reproductive anatomy and gametogenesis (the male and female organs, semen and the accessory glands, and spermatogenesis and oogenesis by meiosis); the hormonal control of reproduction (the hypothalamic-pituitary-gonadal axis, testosterone, estradiol and progesterone, the ovarian and menstrual cycles, and menopause); human pregnancy and birth (implantation and beta-HCG, the placenta, the three trimesters, labor and lactation, contraception, infertility, and assisted reproduction); early embryonic development (fertilization and blocks to polyspermy, cleavage, the blastula and blastocyst, and gastrulation into the three germ layers); and organogenesis and vertebrate body formation (neural tube, somites, notochord, body axes, and left-right asymmetry).
- Ecology and the BiosphereRecall cards on ecology and the biosphere: the scope of ecology and its four levels of organization (organism, population, community, and ecosystem), species interactions, and mutualism; biogeography, endemic versus generalist species, and the abiotic factors (light, temperature, water, inorganic nutrients, oxygen, wind, and fire) that shape where organisms live, including lake turnover, upwelling, migration, torpor, and net primary productivity; the terrestrial biomes (tropical wet forest, savanna, subtropical desert, chaparral, temperate grassland, temperate forest, boreal forest, and Arctic tundra) with their climate, vegetation, and soils; the aquatic biomes (ocean zones, coral reefs and bleaching, estuaries, lakes and ponds, rivers and streams, and wetlands); and climate versus weather, the ice-core record, Milankovitch cycles, the greenhouse effect and greenhouse gases, the rise in atmospheric carbon dioxide, methane and clathrate feedback, glacier and ice loss, sea-level rise, and phenology shifts.
- Population and Community EcologyRecall cards on population and community ecology: population demography (size, density, dispersion patterns, quadrat and mark-recapture sampling, life tables, and Type I, II, and III survivorship curves); life histories and natural selection (energy budgets, fecundity, semelparity versus iteroparity, and the cost of reproduction); environmental limits to growth (exponential J-curves, the per capita rate of increase, carrying capacity, and logistic growth); population dynamics (density-dependent versus density-independent regulation and K- versus r-selection); human population growth and age structure; community ecology (predation and the lynx-hare cycle, defenses and mimicry, competitive exclusion, symbiosis, foundation and keystone species, invasive species, and succession); and behavioral biology (innate versus learned behavior, kinesis and taxis, fixed action patterns, migration, foraging, communication, mating systems and sexual selection, conditioning, and kin selection and altruism).
- EcosystemsRecall cards on ecosystems: the ecology of ecosystems (freshwater, marine, and terrestrial categories; equilibrium, resistance, and resilience; food chains, trophic levels, and food webs; grazing and detrital food webs; and conceptual, analytical, and simulation models); energy flow through ecosystems (photoautotrophs and chemoautotrophs; gross and net primary productivity; trophic level transfer efficiency and net production efficiency; ecological pyramids of numbers, biomass, and energy; and biomagnification of DDT, PCBs, and heavy metals); and biogeochemical cycles (the water, carbon, nitrogen, phosphorus, and sulfur cycles, including nitrogen fixation, ammonification, nitrification, and denitrification, eutrophication and dead zones, and acid rain).
- Conservation Biology and BiodiversityRecall cards on conservation biology and biodiversity: the biodiversity crisis (genetic, species, and ecosystem diversity; how many species exist and how many are named; the equatorial gradient, endemism, and biodiversity hotspots; the five mass extinctions and the present sixth; background versus current extinction rates; and the species-area relationship); the importance of biodiversity to human life (medicines from plants and animals; crop wild relatives and seed banks; soil organisms, pollinators and colony collapse, natural pest control, and fisheries); threats to biodiversity (habitat loss, overharvesting, invasive species, and climate change); and preserving biodiversity (DNA barcoding; CITES, the Endangered Species Act, and the Migratory Bird Treaty Act; nature preserve design and island biogeography; keystone species; and captive breeding).
- Essential Ideas (Chemistry)Recall cards on the essential ideas of chemistry: chemistry in context (the central science; hypothesis, law, and theory; the macroscopic, microscopic, and symbolic domains); phases and classification of matter (the states of matter and plasma; mass versus weight; conservation of matter; pure substances, elements, compounds, and mixtures; atoms and molecules); physical and chemical properties and changes (extensive versus intensive properties; the NFPA hazard diamond); measurements (SI base units and metric prefixes; volume and density); measurement uncertainty (significant figures, rounding, accuracy versus precision); and the mathematical treatment of measurements (dimensional analysis, conversion factors, and temperature scales).
- Atoms, Molecules, and Ions (Chemistry)Recall cards on atoms, molecules, and ions: early ideas in atomic theory (Dalton's postulates; the laws of conservation of matter, definite proportions, and multiple proportions); the evolution of atomic theory (Thomson's cathode rays and the electron; Millikan's oil drop experiment; the plum pudding model; Rutherford's gold foil experiment and the nucleus; the proton, neutron, and isotopes); atomic structure and symbolism (the atomic mass unit; atomic number, mass number, and neutron count; isotope notation; ions, cations, and anions; average atomic mass); chemical formulas (molecular, empirical, and structural formulas; molecular models); the periodic table (the periodic law; periods and groups; metals, nonmetals, and metalloids; the element families); molecular and ionic compounds (ionic and covalent bonds; ion charges; monatomic and polyatomic ions); and chemical nomenclature (naming ionic compounds and the Stock system, binary molecular compounds, and acids).
- Composition of Substances and Solutions (Chemistry)Recall cards on the composition of substances and solutions: formula mass and the mole concept (formula versus molecular mass; the mole and Avogadro's number; molar mass and mass-mole-entity conversions); determining empirical and molecular formulas (percent composition; deriving an empirical formula from element masses or percent composition; the whole-number multiple linking empirical and molecular formulas); molarity (solution, solvent, solute, and aqueous solution; concentration; molarity and its unit; dilution and the dilution equation); and other units for solution concentrations (mass percentage, volume percentage, mass-volume percent, parts per million, and parts per billion).
- Stoichiometry of Chemical Reactions (Chemistry)Recall cards on the stoichiometry of chemical reactions: writing and balancing chemical equations (reactants, products, coefficients, subscripts, conservation of matter, state symbols, and molecular, complete-ionic, and net-ionic equations); classifying chemical reactions (precipitation and solubility rules; Arrhenius acids and bases, strong versus weak, and neutralization; oxidation-reduction, oxidation numbers, oxidizing and reducing agents, combustion, and single displacement); reaction stoichiometry (the mole ratio and mass-to-mass calculations); reaction yields (limiting and excess reactants, and theoretical, actual, and percent yield); and quantitative chemical analysis (titration, gravimetric analysis, and combustion analysis).
- Thermochemistry (Chemistry)Recall cards on thermochemistry: energy basics (energy, work, kinetic and potential energy, conservation of energy, thermal energy, temperature, heat, exothermic and endothermic processes, the calorie and joule, heat capacity, specific and molar heat capacity, and q = m c deltaT); calorimetry (calorimeters, system and surroundings, coffee-cup and bomb calorimeters, hand warmers and cold packs, and food energy); and enthalpy (internal energy, the first law of thermodynamics, pressure-volume work, state functions, enthalpy and enthalpy change, thermochemical equations, standard states, standard enthalpies of combustion and formation, and Hess's law).
- Electronic Structure and Periodic Properties (Chemistry)Recall cards on the electronic structure of atoms and periodic trends: electromagnetic energy (wavelength, frequency, the speed of light, blackbody radiation, quantization, photons, the photoelectric effect, line spectra, the Rydberg formula, and wave-particle duality); the Bohr model of hydrogen (stationary states, quantized orbital energies, ground and excited states, the Bohr radius, and ionization); the development of quantum theory (de Broglie wavelength, the Heisenberg uncertainty principle, wavefunctions and atomic orbitals, the four quantum numbers, the Pauli exclusion principle, and orbital shapes); electron configurations (the Aufbau principle, Hund's rule, subshell filling order, valence and core electrons, noble gas notation, ion configurations, and the periodic table blocks); and periodic variations (atomic and ionic radii, effective nuclear charge, ionization energy, electron affinity, and metallic character).
- Chemical Bonding and Molecular Geometry (Chemistry)Recall cards on chemical bonding and molecular shape: ionic bonding (ions, cations and anions, ionic bonds and the properties of ionic solids, cation and anion formation rules, and lattice arrangement); covalent bonding (shared electron pairs, bond length, the properties of covalent compounds, pure versus polar covalent bonds, and electronegativity and its periodic trends); Lewis symbols and structures (lone and bonding pairs, the octet rule and its exceptions, single, double, and triple bonds, and free radicals, electron-deficient, and hypervalent molecules); formal charges and resonance (the formal-charge formula, structure selection, and resonance forms and hybrids); the strengths of ionic and covalent bonds (bond energy, bond order, reaction enthalpy from bond energies, lattice energy, and the Born-Haber cycle); and molecular structure and polarity (VSEPR theory, the five electron-pair geometries and their bond angles, lone-pair effects, bond dipole moments, and molecular polarity).
- Advanced Theories of Covalent Bonding (Chemistry)Recall cards on advanced covalent bonding theory: valence bond theory (the overlap of half-filled atomic orbitals, orbital overlap and bond strength, the energy of bond formation and bond distance, and sigma and pi bonds in single, double, and triple bonds); hybrid atomic orbitals (hybridization and its relation to VSEPR electron-pair geometry, and the sp, sp2, sp3, sp3d, and sp3d2 hybrid sets with their geometries and bond angles); multiple bonds (the sigma-plus-pi description of double and triple bonds in ethene and acetylene, restricted rotation about double bonds, and delocalization in benzene); and molecular orbital theory (bonding and antibonding molecular orbitals from the linear combination of atomic orbitals, molecular orbital diagrams, bond order, paramagnetism and diamagnetism, the paramagnetism of oxygen, and s-p mixing in second-period diatomic molecules).
- Gases (Chemistry)Recall cards on the behavior of gases: gas pressure (its definition as force per area, its origin in molecular collisions, the pascal, atmosphere, torr, mm Hg, bar, and psi units and their conversions, barometers and manometers, and hydrostatic pressure); the simple gas laws (Amontons's/Gay-Lussac's, Charles's, Boyle's, and Avogadro's laws with their equations) and the ideal gas law PV = nRT with the gas constant, standard temperature and pressure, the standard molar volume, the combined gas law, and absolute zero; gas stoichiometry (gas density and molar mass from the ideal gas law, the law of combining volumes, Dalton's law of partial pressures, mole fraction, and collecting a gas over water); effusion and diffusion (mean free path, Graham's law, and uranium enrichment); the kinetic-molecular theory (its postulates, molecular kinetic energy, root-mean-square speed, and the Maxwell-Boltzmann distribution); and non-ideal gas behavior (deviations at high pressure and low temperature, the compressibility factor, and the van der Waals equation).
- Liquids and Solids (Chemistry)Recall cards on the condensed phases of matter: intermolecular forces (the distinction from intramolecular forces, van der Waals forces, dispersion/London forces and polarizability, dipole-dipole attractions, and hydrogen bonding); the properties of liquids (viscosity, cohesion and adhesion, surface tension, and capillary action); phase transitions (vaporization and condensation, vapor pressure, boiling point, the Clausius-Clapeyron equation, melting and freezing, sublimation and deposition, and the associated enthalpies); phase diagrams (their axes and regions, the solid-liquid, liquid-gas, and solid-gas curves, the triple point, and the critical point); the solid state (crystalline versus amorphous solids and the four types of crystalline solid: ionic, metallic, covalent network, and molecular, plus crystal defects and doping); and lattice structures (the unit cell, simple cubic, body-centered cubic, and face-centered cubic structures with their coordination numbers and packing efficiencies, closest packing, tetrahedral and octahedral holes, the sodium chloride structure, and X-ray diffraction with the Bragg equation).
- Solutions and Colloids (Chemistry)Recall cards on solutions and colloids: the dissolution process (solute and solvent, the spontaneity and entropy of solution formation, ideal solutions, the three intermolecular attractions involved, and endothermic versus exothermic dissolving); electrolytes (strong, weak, and nonelectrolytes, dissociation, ion-dipole attraction, and covalent compounds that ionize by reacting with water); solubility (saturated, unsaturated, and supersaturated solutions, Henry's law for gases, miscibility, and the temperature dependence of solubility); colligative properties (mole fraction and molality, Raoult's law, vapor pressure lowering, boiling point elevation and freezing point depression with their constants, osmosis and osmotic pressure, and the van't Hoff factor); and colloids (the dispersed phase and dispersion medium, the Tyndall effect, sols, aerosols, emulsions, gels and foams, emulsifying agents, soaps and detergents, charged colloidal particles, the Cottrell precipitator, and gels).
- Kinetics (Chemistry)Recall cards on chemical kinetics: reaction rates (average, instantaneous, and initial rates, the sign convention, rates from the tangent to a concentration-versus-time curve, and stoichiometric rate relations); the factors that affect rates (chemical nature, physical state and surface area, temperature, concentration, and catalysts); rate laws (the rate constant, reaction order, the method of initial rates, and the units of k); integrated rate laws (the first-, second-, and zero-order equations, their linear plots, and their half-lives); collision theory (activation energy, the activated complex, and the Arrhenius equation with its linear form and plot); reaction mechanisms (elementary reactions, intermediates, molecularity, and the rate-determining step); and catalysis (lower-activation-energy pathways, homogeneous versus heterogeneous catalysts, and enzymes).
- Fundamental Equilibrium Concepts (Chemistry)Recall cards on the fundamentals of chemical equilibrium: reversible reactions and dynamic equilibrium (equal forward and reverse rates, constant concentrations, the double arrow); the reaction quotient Q and the equilibrium constant K (the concentration form Qc and the pressure form Qp, the law of mass action, what large and small K values mean, using Q versus K to predict reaction direction, the relation Kp = Kc(RT)^delta-n, and homogeneous versus heterogeneous equilibria with pure solids and liquids omitted); manipulating equilibrium constants for reversed, multiplied, and combined reactions; Le Chatelier's principle (how concentration, pressure-volume, and temperature changes shift an equilibrium, why a catalyst does not, and the Haber process and carbonated-drink examples); and equilibrium calculations with ICE tables, the quadratic formula, and the small-K approximation.
- Acid-Base Equilibria (Chemistry)Recall cards on aqueous acid-base equilibria: the Bronsted-Lowry model (proton donors and acceptors, conjugate acid-base pairs, amphiprotic species, and the autoionization of water with its ion-product constant Kw); the pH and pOH scales (their definitions, the 25 C relation pH + pOH = 14, and acidic, neutral, and basic ranges); relative acid and base strengths (strong versus weak, Ka and Kb, percent ionization, the Ka x Kb = Kw relation for a conjugate pair, the leveling effect, and molecular-structure trends in binary and oxyacids); salt hydrolysis and the acidity of hydrated metal ions; polyprotic acids and their successive ionization constants; buffers (composition, action, capacity, and the Henderson-Hasselbalch equation); and acid-base titrations (titration curves, equivalence and end points, and indicator choice).
- Equilibria of Other Reaction Classes (Chemistry)Recall cards on solubility and other equilibria beyond simple acid-base systems: precipitation and dissolution (the solubility product constant Ksp, molar solubility, saturated, unsaturated, and supersaturated solutions, the ion product Qsp and its comparison with Ksp to predict precipitation, the common ion effect, selective precipitation, and pH-controlled solubility); Lewis acids and bases (electron-pair donors and acceptors, coordinate covalent bonds, acid-base adducts, complex ions and their ligands, and the formation constant Kf); and coupled equilibria (shared species linking two equilibria, the product-of-K rule, acid-enhanced solubility of basic-anion salts, and complex-ion driven dissolution), with applications including ocean acidification of calcium carbonate and the fluoridation of tooth enamel.
- Thermodynamics (Chemistry)Recall cards on chemical thermodynamics: spontaneity (spontaneous and nonspontaneous processes, the independence of spontaneity from reaction speed, and the dispersal of matter and energy); entropy (the state function S, delta-S = q_rev/T, Boltzmann's S = k ln W and microstates, and how entropy varies with state of matter, phase change, temperature, and dissolution); the second and third laws (the entropy of the universe, delta-S_univ sign rules for spontaneity and equilibrium, the entropy change of the surroundings, and the zero entropy of a perfect crystal at 0 K); and Gibbs free energy (G = H - TS, delta-G = delta-H - T delta-S, the delta-G sign criterion, standard free energies of reaction and formation, delta-G = delta-G degree + RT ln Q, delta-G degree = -RT ln K, and the temperature dependence of spontaneity).
- Electrochemistry (Chemistry)Recall cards on electrochemistry: a review of redox chemistry (oxidation numbers and their rules, oxidants and reductants, and the half-reaction method for balancing redox equations); galvanic cells (half-cells, anode and cathode, salt bridges, active and inert electrodes, and cell notation); electrode and cell potentials (the volt, standard cell potential, the standard hydrogen electrode, tabulated standard reduction potentials, and predicting spontaneity); the links among potential, free energy, and equilibrium (delta-G = -nFE, Faraday's constant, the relationship of E-degree-cell to K, and the Nernst equation); batteries and fuel cells (primary and secondary cells, the dry, alkaline, NiCd, lithium-ion, and lead-acid batteries, and the hydrogen fuel cell); corrosion (the electrochemistry of rusting and methods of protection such as galvanization, passivation, and sacrificial anodes); and electrolysis (electrolytic cells, overpotential, the Downs and chlor-alkali processes, and the stoichiometry relating charge to amount of substance produced).
- Representative Metals, Metalloids, and Nonmetals (Chemistry)Recall cards on the descriptive chemistry of the representative elements: periodicity and the periodic behavior of the representative metals (alkali, alkaline earth, group 12, and the metals of groups 13 to 15, plus the inert pair effect and allotropes); the occurrence and preparation of the representative metals (electrolysis in the Downs and Hall-Heroult cells, and chemical reduction such as the Pidgeon process); the structure and properties of the six metalloids (boron, silicon, germanium, arsenic, antimony, and tellurium) and their oxides, halides, and silicates; the structure and properties of the nonmetals (carbon allotropes, phosphorus and sulfur allotropes, and periodic trends); hydrogen and its compounds (isotopes, preparation, ammonia and the Haber process, the hydrogen halides); carbonates and hydrogen carbonates; and the occurrence, preparation, and properties of nitrogen, phosphorus, oxygen (including ozone, oxides, peroxides, superoxides, and hydroxides), sulfur, the halogens, and the noble gases.
- Transition Metals and Coordination Chemistry (Chemistry)Recall cards on the transition metals and coordination chemistry: the properties of the transition metals and inner transition metals (lanthanides and actinides), their electron configurations, oxidation states, and periodic trends; the occurrence, extraction, and refining of transition metals (roasting, smelting, the blast furnace, steelmaking, copper extraction, and silver hydrometallurgy); the preparation and chemistry of transition metal halides, oxides, hydroxides, and carbonates; coordination compounds and complexes (ligands, denticity, chelates, coordination number and geometry, nomenclature, and the many kinds of isomerism); the biological and industrial roles of coordination compounds (hemoglobin, chlorophyll, cisplatin, EDTA, and catalysis); and crystal field theory, including octahedral, tetrahedral, and square planar d-orbital splitting, high-spin versus low-spin complexes, the spectrochemical series, and the origins of color and magnetism in coordination compounds.
- Organic Chemistry (Chemistry)Recall cards on organic chemistry: the hydrocarbons (alkanes, alkenes, alkynes, and aromatic compounds), their bonding, hybridization, reactions (substitution and addition), isomerism (constitutional and geometric), and IUPAC naming; the oxygen-containing functional groups including alcohols and ethers; the carbonyl compounds aldehydes, ketones, carboxylic acids, and esters, their functional groups, nomenclature, oxidation and reduction relationships, and everyday examples; and the nitrogen-containing amines and amides, including amidation, peptide bonds, proteins, enzymes, and polyamides such as Kevlar.
- Nuclear Chemistry (Chemistry)Recall cards on nuclear chemistry: nuclear structure and stability (nucleons, atomic and mass numbers, isotopes, the strong force, mass defect and binding energy, the band of stability, and magic numbers); writing and balancing nuclear equations with alpha, beta, positron, and gamma particles; radioactive decay (alpha, beta, gamma, positron emission, and electron capture, half-life, first-order kinetics, and radiometric dating); transmutation and nuclear energy (particle accelerators, transuranium elements, fission, chain reactions, reactor design, and fusion); uses of radioisotopes (medical tracers, therapy, and smoke detectors); and the biological effects of radiation (ionizing versus nonionizing radiation, penetrating power and shielding, the units becquerel, curie, gray, rad, sievert, and rem, relative biological effectiveness, radon, dose limits, and detectors).
- Units and Measurement (Physics)Recall cards on units and measurement: the scope and scale of physics (physics as a science, orders of magnitude, models, theories, and laws, and the length, mass, and time scales of the universe); units and standards (physical quantities, base versus derived quantities, the seven SI base quantities and units, the modern second and meter standards, and metric prefixes); unit conversion with conversion factors; dimensional analysis (the base-dimension symbols L, M, T, I, theta, N, and J, dimensionless quantities, dimensional consistency, and transcendental arguments); estimates and Fermi calculations; significant figures (accuracy versus precision, uncertainty versus discrepancy, percent uncertainty, counting significant figures, and the rules for arithmetic operations and exact numbers); and the three-stage strategy for solving physics problems.
- Vectors (Physics)Recall cards on vectors: scalars versus vectors (magnitude and direction, notation, displacement, equal, parallel, antiparallel, orthogonal, and negative vectors, scalar multiplication, resultants, the commutative, associative, and distributive laws, the parallelogram and tail-to-head rules, unit vectors, and vector subtraction); coordinate systems and components (vector and scalar components, the unit vectors i-hat, j-hat, and k-hat, component form, magnitude and direction angle from components, quadrant rules, polar coordinates, and right-handed axes); the algebra of vectors (the analytical component method, component-wise addition, subtraction, and scalar multiplication, equality, the null vector, and unit vectors from magnitude); and the products of vectors (the scalar or dot product and the vector or cross product, their properties, unit-vector identities, component forms, and the applications to work and torque).
- Motion Along a Straight Line (Physics)Recall cards on one-dimensional kinematics: position and frame of reference; displacement as the change in position (final minus initial), a vector measured in meters, and its distinction from distance traveled; average velocity as displacement over elapsed time; instantaneous velocity as the time derivative of position and the slope of a position-versus-time graph; speed as a scalar and instantaneous speed as the magnitude of velocity; average and instantaneous acceleration as the rate of change of velocity and the slope of a velocity-versus-time graph, with the sign conventions relating acceleration and velocity direction to speeding up or slowing down; the constant-acceleration kinematic equations and the notation behind them; free fall under gravity alone with acceleration g directed downward; and finding velocity and displacement by integrating acceleration and velocity over time.
- Motion in Two and Three Dimensions (Physics)Recall cards on kinematics in two and three dimensions: the position, displacement, and velocity vectors in unit-vector notation and their component forms; instantaneous velocity as the derivative of position and always tangent to the path; the acceleration vector as the first derivative of velocity and the second derivative of position; the independence of motion along perpendicular axes and the constant-acceleration equations applied per axis; projectile motion with zero horizontal acceleration and downward gravity, including the launch components, time of flight, maximum height, range, the 45-degree maximum, complementary launch angles, and the parabolic trajectory; uniform and nonuniform circular motion, centripetal acceleration expressed through speed, period, and angular frequency, and tangential and total acceleration; and relative motion, with the addition rules for position, velocity, and acceleration across reference frames and the invariance of acceleration between frames moving at constant relative velocity.
- Newton's Laws of Motion (Physics)Recall cards on Newton's laws of motion: force as a vector push or pull measured in newtons, external versus contact versus field forces, the four fundamental forces, and the net force as a vector sum; Newton's first law, inertia and its measure by mass, inertial reference frames, and equilibrium under zero net force; Newton's second law in scalar and vector form, F_net = m a and its momentum form F_net = dp/dt, with the proportionalities between force, mass, and acceleration; mass versus weight, w = m g, and how weight varies with local gravity while mass does not; Newton's third law and action-reaction pairs acting on different bodies, including thrust; common forces such as the normal force, tension, friction, Hooke's-law spring restoring force, and the real-versus-fictitious distinction; and how to draw and use free-body diagrams to apply Newton's second law.
- Applications of Newton's Laws (Physics)Recall cards on applying Newton's laws: the systematic problem-solving strategy of sketching the situation, drawing a free-body diagram of the external forces, applying Newton's second law per coordinate axis, and checking the result; static and dynamic equilibrium, tension in a massless string over a frictionless pulley, apparent weight and elevator problems, and connected objects. Friction as a contact force opposing relative motion, static versus kinetic friction, the laws f_s <= mu_s N and f_k = mu_k N, the dimensionless coefficients of friction, area independence, and the microscopic origins of friction. Centripetal acceleration and force in uniform circular motion, F_c = m v^2/r = m r omega^2, ideally banked curves with theta = arctan(v^2/rg), inertial versus noninertial reference frames, and the fictitious centrifugal and Coriolis forces. And drag force through a fluid, F_D = (1/2) C rho A v^2, the drag coefficient, terminal velocity v_T = sqrt(2mg/(rho C A)), and Stokes' law for small slow objects.
- Work and Kinetic Energy (Physics)Recall cards on work and kinetic energy: work as the transfer of energy when a force acts through a displacement, the infinitesimal work dW = F.dr, the constant-force result W = Fd cos(theta), the parallel-component rule, work as a line integral or the area under a force-versus-displacement curve, the sign of work, the joule and foot-pound, and the work done by friction, gravity, and a spring, including conservative versus dissipative forces and the zero work around a closed path. Kinetic energy K = (1/2)mv^2 as a non-negative scalar that depends on speed and reference frame, its joule unit, the momentum form K = p^2/(2m), and translational versus rotational kinetic energy. The work-energy theorem W_net = K_f - K_i derived from Newton's second law, its use for variable forces and curved frictionless paths, and the consequences of positive, negative, and zero net work. And power as the rate of doing work, average power W/t, instantaneous power dW/dt = F.v, the watt, and the horsepower.
- Potential Energy and Conservation of Energy (Physics)Recall cards on potential energy and the conservation of energy: potential energy as energy stored in a system because of the configuration of its interacting objects, the rule that the change in potential energy is the negative of the work done by the associated conservative force, the arbitrary additive constant and the choice of a zero reference, gravitational potential energy U = mgy near Earth's surface, and elastic potential energy U = (1/2)kx^2 for a spring. Conservative forces (path-independent work, zero work around a closed path) versus non-conservative dissipative forces such as friction and air resistance, recovering a conservative force from its potential energy by F = -dU/dx or the gradient, and the curl test. Mechanical energy E = K + U, its conservation when only conservative forces do work, W_nc = change in E when they do not, and the law of conservation of energy. Potential energy diagrams: the total-energy line, the condition K = E - U >= 0, turning points, allowed and forbidden regions, force as minus the slope, equilibrium points, stable versus unstable equilibria from the second derivative, maximum speed at a potential minimum, and the infinite potential well. And sources of energy: thermal, chemical, radiant, and nuclear energy, renewable versus nonrenewable sources, conversion losses, hydro, wind, and solar power, and the 2010 world energy shares.
- Linear Momentum and Collisions (Physics)Recall cards on linear momentum and collisions: linear momentum p = mv as a vector pointing along the velocity, measured in kg·m/s, characterizing an object's quantity of motion and depending linearly on mass and velocity. Impulse J as force times time, the infinitesimal and integral forms, the impulse-momentum theorem J = delta p, Newton's second law as F = dp/dt, and the average force in a collision. Conservation of linear momentum for a closed system, why internal Newton's-third-law pairs cancel while external forces change total momentum. Types of collisions: momentum always conserved, kinetic energy conserved only in elastic collisions, inelastic and perfectly inelastic collisions, and explosions. Collisions in multiple dimensions with per-direction conservation and component equations. The center of mass as the weighted average position of mass, r_CM and its component and integral forms, F_ext = M a_CM, and the constant center-of-mass velocity of a system with zero external force. And rocket propulsion as a variable-mass system, exhaust velocity, the Tsiolkovsky rocket equation delta v = u ln(m_0/m), and the effect of gravity on a launch.
- Fixed-Axis Rotation (Physics)Recall cards on the rotation of a rigid body about a fixed axis. Rotational variables: angular position theta = s/r in radians, angular displacement, angular velocity omega = d theta/dt, and angular acceleration alpha = d omega/dt, with the counterclockwise-positive sign convention and the right-hand rule for the direction of the angular velocity vector. Rotation with constant angular acceleration: the four rotational kinematic equations as direct analogs of the linear ones (theta for x, omega for v, alpha for a). Relating angular and translational quantities: tangential speed v_t = r omega, tangential acceleration a_t = r alpha, centripetal acceleration a_c = r omega^2, and the total linear acceleration. Moment of inertia and rotational kinetic energy: K = (1/2) I omega^2, I = sum m r^2 as the rotational analog of mass, and its dependence on the axis and the mass distribution. Calculating moments of inertia: the integral I = integral r^2 dm, the parallel-axis theorem I = I_cm + m d^2, and standard results for a rod (about center and end), a disk, and compound bodies. Torque tau = r x F, its magnitude r F sin theta, the lever arm, net torque, and its sign. Newton's second law for rotation, sum tau = I alpha, the rotational analog of F = ma. And work and power for rotational motion, W = integral tau d theta, the work-energy theorem, and P = tau omega.
- Angular Momentum (Physics)Recall cards on angular momentum and rolling motion. Rolling without slipping: the contact point is instantaneously at rest, v_CM = R omega, a_CM = R alpha, and d_CM = R theta; the acceleration down an incline a_CM = m g sin(theta)/(m + I_CM/r^2), the static-friction bound needed to prevent slipping, and the split of kinetic energy into translational (1/2) m v_CM^2 plus rotational (1/2) I_CM omega^2 with friction doing no work. Angular momentum of a particle: l = r x p, magnitude r p sin(theta), direction by the right-hand rule, the lever-arm form l = r_perp m v, and the unit kg m^2/s. The rotational form of Newton's second law, sum tau = dl/dt, and for a system sum tau_ext = dL/dt. Angular momentum of a rigid body, L = I omega, directed along the rotation axis. Conservation of angular momentum when the net external torque is zero: I omega = I' omega', the ice-skater effect, and the rise in rotational kinetic energy K'_rot = K_rot (I/I'). And the precession of a gyroscope: gravitational torque tau = r M g sin(theta) perpendicular to L, the precession rate omega_p = r M g/(I omega), nutation, and Earth's 26,000-year precession.
- Static Equilibrium and Elasticity (Physics)Recall cards on the static equilibrium of rigid bodies and on stress, strain, and elasticity. Static equilibrium requires zero linear and zero angular acceleration: the first condition sets the vector sum of external forces to zero (translational equilibrium), and the second sets the sum of external torques about any axis to zero (rotational equilibrium), both at once. For rotation about a fixed z-axis the six scalar equations reduce to three, torque magnitude is r F sin(theta), the pivot may be chosen freely, and weight acts at the center of gravity. Solving equilibrium problems: free-body diagrams with forces at their real points of application, choosing the pivot to cancel an unknown, statically indeterminate cases, and the normal, friction, tension, and hinge forces involved. Stress is force per unit area and strain is the dimensionless fractional deformation; within the linear limit stress = elastic modulus times strain, measured in pascals. Tensile, compressive, bulk, and shear stress and strain define Young's modulus, the bulk modulus, and the shear modulus. Elasticity, the proportionality and elastic limits, Hooke's law, the plastic region, permanent deformation, and the fracture (breaking) stress.
- Gravitation (Physics)Recall cards on Newtonian gravity and its consequences. Newton's law of universal gravitation gives an attractive, inverse-square force F = G m1 m2 / r^2 along the line joining two masses, with the universal constant G first measured by Cavendish; spherically symmetric bodies act as though their mass sits at the center, and net forces add by superposition. Gravitation near Earth's surface: g = GM/r^2, weight W = mg, the fall of all masses at the same rate, and the small corrections from altitude, Earth's rotation, and its equatorial bulge. Gravitational potential energy U = -GMm/r (zero at infinity), conservation of total mechanical energy, escape velocity sqrt(2GM/R), and gravitational binding. Satellite orbits: circular orbital speed and period, orbital energy E = -GMm/2r, geostationary orbits, and weightlessness in free fall. Kepler's three laws of planetary motion (ellipses, equal areas, and the period-axis relation) and their basis in angular momentum and the inverse-square force. Tidal forces, spring and neap tides, tidal locking, and Io's heating. Finally Einstein's theory of gravity: the equivalence principle, spacetime curvature, the Schwarzschild radius and black holes, gravitational lensing, and time dilation.
- Fluid Mechanics (Physics)Recall cards on the mechanics of fluids at rest and in motion. Density rho = m/V, specific gravity, and the states of matter. Pressure p = F/A as a scalar that acts equally in all directions and increases with depth as p = p0 + rho g h. Measuring pressure: gauge versus absolute pressure, the pascal and other units, and the barometer and manometer. Pascal's principle and how hydraulic systems multiply force without creating extra work. Archimedes' principle and buoyancy: the buoyant force equals the weight of displaced fluid, and floating, sinking, and apparent weight follow from density. Fluid dynamics: flow rate, the equation of continuity, laminar versus turbulent flow, and ideal fluids. Bernoulli's equation as energy conservation along a streamline, Bernoulli's principle relating speed and pressure, and entrainment. Finally viscosity, the Reynolds number, Poiseuille's law and its strong dependence on tube radius, and the onset of turbulence.
- Oscillations (Physics)Recall cards on oscillatory motion. Periodic motion, period and frequency, and amplitude. Simple harmonic motion (SHM) as the motion of a Hooke's-law restoring force: position x(t) = A cos(omega t + phi), its velocity and acceleration, angular frequency omega = sqrt(k/m), and the period T = 2 pi sqrt(m/k) that depends only on mass and spring constant. Energy in SHM: elastic potential and kinetic energy, the conserved total E = (1/2) k A^2 proportional to amplitude squared, and the speed at any position. SHM as the projection of uniform circular motion. Pendulums: the simple pendulum with T = 2 pi sqrt(L/g), the physical pendulum, and the torsional pendulum. Damped oscillations: the velocity-proportional damping force, exponential amplitude decay, and the underdamped, critically damped, and overdamped regimes. Forced oscillations: natural frequency, steady-state amplitude, and resonance when the driving frequency matches the natural frequency.
- Waves (Physics)Recall cards on traveling and standing waves. Mechanical waves in a medium versus electromagnetic and matter waves. Amplitude, wavelength, period, and frequency, and the wave-speed relations v = lambda/T = lambda*f. Transverse versus longitudinal (compressional) waves. The mathematics of waves: the sinusoidal wave function y = A sin(kx - omega t + phi), wave number k = 2 pi/lambda, angular frequency omega = 2 pi/T, the phase and phase constant, transverse velocity and acceleration of a medium element, and the linear wave equation. Wave speed on a stretched string v = sqrt(F_T/mu) and the general elastic-over-inertial form. Energy and power of a wave: P = (1/2) mu A^2 omega^2 v, the amplitude-squared and frequency-squared scaling, intensity I = P/A, and the inverse-square law for a point source. Interference and superposition: constructive and destructive interference and the resultant amplitude 2A cos(phi/2). Standing waves and resonance: nodes and antinodes, the standing-wave function y = 2A sin(kx) cos(omega t), allowed wavelengths lambda_n = 2L/n and resonant frequencies f_n = n f_1 on a string fixed at both ends, harmonics, overtones, normal modes, and resonance.
- Sound (Physics)Recall cards on sound as a longitudinal disturbance of matter that travels outward through a medium. Compressions and rarefactions, the sinusoidal pressure and displacement variations and their quarter-cycle phase difference, and the wave-speed relation v = omega/k = lambda*f. The speed of sound: about 331 m/s in dry air at 0 C, 343 m/s at 20 C, its dependence on absolute temperature v = 331*sqrt(T/273 K), and the forms v = sqrt(Y/rho) in a solid rod and v = sqrt(gamma R T/M) in an ideal gas. Sound intensity I = P/A, the inverse-square falloff, the pressure-amplitude relation, the threshold of hearing 10^-12 W/m^2, and the decibel scale beta = 10 log10(I/I0). Standing sound waves and normal modes: nodes and antinodes, tubes open at both ends (all harmonics, lambda_1 = 2L) versus closed at one end (odd harmonics only, lambda_1 = 4L), fundamentals, overtones, and harmonics. Sources of musical sound and timbre, the end correction, beats and the beat frequency |f1 - f2|, the Doppler effect for moving source and moving observer, and shock waves, the Mach number, the sonic boom, and the shock-cone half-angle sin(theta) = 1/M.
- Temperature and Heat (Physics)Recall cards on temperature, heat, and heat transfer. Temperature as what a thermometer measures and as a measure of average translational kinetic energy, thermal equilibrium, and the zeroth law of thermodynamics. The Celsius, Fahrenheit, and Kelvin scales, their fixed points, the conversion formulas, and absolute zero (0 K = -273.15 C). Thermal expansion: linear (delta L = alpha L delta T), area (delta A = 2 alpha A delta T), and volume (delta V = beta V delta T with beta = 3 alpha), thermal stress, and water's density maximum near 4 C. Heat, the calorie and the mechanical equivalent of heat (1 kcal = 4186 J), specific heat and Q = mc delta T, and calorimetry (Q_cold + Q_hot = 0). Phase changes: melting, vaporization, and sublimation, the pressure dependence of melting and boiling points, latent heats of fusion and vaporization (water 334 kJ/kg and 2256 kJ/kg), phase diagrams, the triple point, and the critical point. The three mechanisms of heat transfer: conduction (P = kA(T_h - T_c)/d and the R-factor), convection (forced and natural), and radiation via the Stefan-Boltzmann law P = sigma A e T^4.
- The Kinetic Theory of Gases (Physics)Recall cards on the kinetic theory of gases. The ideal gas law in molecular form (pV = N k_B T) and molar form (pV = nRT), the Boltzmann constant, Avogadro's number, the universal gas constant R = N_A k_B, moles and molar mass, and the empirical Boyle, Charles, and Amonton laws. Standard temperature and pressure, the 22.4 L molar volume, and the van der Waals equation for real gases. The molecular model: kinetic-theory assumptions, pressure from wall collisions (pV = (1/3) N m (v^2)avg), average translational kinetic energy K_avg = (3/2) k_B T, the rms speed v_rms = sqrt(3 k_B T / m) = sqrt(3 R T / M), monatomic internal energy (3/2) nRT, Dalton's law of partial pressures, and the mean free path and mean free time. Heat capacity and equipartition: C_V at constant volume, degrees of freedom, the equipartition theorem, C_V = (d/2) R for monatomic (3/2 R), diatomic (5/2 R), and polyatomic (3R) gases, the Dulong-Petit law for solids (3R), and temperature-activated degrees of freedom. The Maxwell-Boltzmann distribution of molecular speeds, the most probable, average, and rms speeds and their ordering (v_p < v_avg < v_rms), and how the distribution shifts with temperature and molecular mass.
- The First Law of Thermodynamics (Physics)Recall cards on the first law of thermodynamics. Thermodynamic systems: system, boundary, and surroundings; open, closed, and isolated systems; thermal equilibrium and the zeroth law; equations of state f(p, V, T) = 0 and pV - nRT = 0; extensive versus intensive variables; and pV diagrams. Work, heat, and internal energy: dW = p dV, W as the integral of p dV and the area under a pV curve, the sign of work in expansion and compression, the path dependence of work, and the work in isothermal (nRT ln(V2/V1)), isobaric (p(V2 - V1)), and isochoric (zero) processes; internal energy as the total molecular energy, E_int = (3/2) nRT for a monatomic ideal gas, and the quasi-static process. The first law itself: Delta E_int = Q - W, the sign conventions for Q and W, the differential form dE_int = dQ - dW, internal energy as a path-independent state function, and the isothermal, cyclic, and isolated-system cases. Thermodynamic processes: isothermal, adiabatic, isobaric, isochoric, cyclic, and non-quasi-static, with Q = W for a cycle. Heat capacities of an ideal gas: C_V and C_p, Q = n C_V Delta T and Q = n C_p Delta T, dE_int = n C_V dT, Mayer's relation C_p = C_V + R, the monatomic, diatomic, and polyatomic values, and C_V = (d/2) R. Adiabatic processes: Q = 0, Delta E_int = -W, pV^gamma = constant, TV^(gamma-1) = constant, the adiabatic index gamma = C_p/C_V > 1, the steeper adiabatic slope, free expansion at constant temperature, and engine knocking.
- The Second Law of Thermodynamics (Physics)Recall cards on the second law of thermodynamics. Reversible and irreversible processes: the definition of each, why nearly all real processes are irreversible, the quasi-static and dissipation-free requirements for reversibility, free expansion and spontaneous heat flow as irreversible processes, and the microscopic origin of irreversibility. Heat engines: the working substance, hot and cold reservoirs, the zero internal-energy change over a cycle, net work W = Q_h - Q_c, and thermal efficiency e = W/Q_h = 1 - Q_c/Q_h. Refrigerators and heat pumps as reversed heat engines: Q_h = Q_c + W, the coefficients of performance K_R and K_P, and why a coefficient of performance can exceed 1. Statements of the second law: the Kelvin and Clausius statements, the impossibility of a perfect heat engine or perfect refrigerator, and the equivalence of the two statements. The Carnot cycle: its four reversible steps (two isothermal, two adiabatic), the Carnot engine, Q_c/Q_h = T_c/T_h, the efficiency e = 1 - T_c/T_h, Carnot's principle, the equal efficiency of all reversible engines, and the Carnot coefficients of performance. Entropy: delta-S = Q/T for a reversible isothermal step, the integral form, entropy as a state function, the zero net entropy change over a reversible cycle, the joule-per-kelvin unit, phase-change entropy, and the entropy statement that total entropy never decreases. Entropy on a microscopic scale: entropy as disorder, the statistical second law, delta-S = nR ln(V2/V1) for isothermal expansion, the third law, and the approach to perfect order at absolute zero.
- Electric Charges and Fields (Physics)Recall cards on electric charge and the electric field. Electric charge: its two types, like-repels-unlike-attracts, the coulomb unit, the elementary charge e = 1.602 x 10^-19 C, quantization, conservation, and the charged constituents of the atom, plus what makes an ion positive or negative. Conductors and insulators: conduction electrons and free charge flow, why excess charge spreads on a conductor, why charge stays put on an insulator, polarization, why a charged object attracts a neutral one, charging by induction, and grounding. Coulomb's law: F = k q1 q2 / r^2, its proportionalities, the permittivity of free space epsilon_0 = 8.85 x 10^-12, Coulomb's constant k = 8.99 x 10^9, the line of action, Newton's third law, and superposition. The electric field: E as force per unit positive charge with F = QE, the newton-per-coulomb unit, the field of a point charge, its direction, its independence from the test charge, and superposition. Continuous charge distributions: linear, surface, and volume charge densities, field by integration, and the uniform field sigma / (2 epsilon_0) of an infinite charged plane. Electric field lines: tangency, where they begin and end, line density and count, why they never cross, and that they are only a visualization. Electric dipoles: the definition, the dipole moment p = q d, the coulomb-meter unit, the zero net force and the torque tau = p x E in a uniform field, the alignment tendency, and permanent versus induced dipoles.
- Gauss's Law (Physics)Recall cards on electric flux and Gauss's law. Electric flux: what it measures, its definition as the dot product of the electric field with an area vector, the symbol Phi, the unit N*m^2/C, its scalar nature, the area vector of flat and closed surfaces, the E*A*cos(theta) form for a uniform field, when flux is maximum or zero, the surface-integral form for a nonuniform field, the exit-positive/enter-negative sign convention, and why the net flux through a surface enclosing no charge is zero. Gauss's law: the statement that net flux equals enclosed charge over epsilon_0, its integral form, the meaning of q_enc, the Gaussian surface, that E is the total field from all charges, why outside charges add zero net flux, why the flux is independent of surface shape, the equivalence to Coulomb's law, the point-charge sphere result, and the role of superposition. Applying Gauss's law: identifying symmetry, matching the Gaussian surface to it, the spherical, cylindrical, and planar symmetry cases, and the field results for a sphere inside and out, an infinite line E = lambda/(2*pi*epsilon_0*r), an infinite plane E = sigma/(2*epsilon_0), parallel plates, and a spherical shell. Conductors in electrostatic equilibrium: the definition, conduction electrons, why the interior field is zero, why excess charge sits on the outer surface, the perpendicular field just outside E = sigma/epsilon_0, cavity induction, charge concentration at sharp points, and electrostatic shielding.
- Electric Potential (Physics)Recall cards on electric potential energy, electric potential, and their applications. Electric potential energy: that the Coulomb force is conservative and path-independent, the symbol U and its joule unit, W = -delta U, the zero reference at infinity, the two-charge result U = k*q*Q/r, Coulomb's constant, and the zero closed-loop line integral. Electric potential and potential difference: V = U/q, the symbol V, test-charge independence, the volt as J/C, delta V = delta U/q, V_B - V_A, voltage, delta U = q*delta V, E = -delta V/delta s in a uniform field, 1 N/C = 1 V/m, and the electron-volt. Calculations of potential: V = k*q/r for a point charge, the 1/r versus 1/r^2 falloff, the scalar nature and algebraic superposition of potential, the electric dipole and its moment p = q*d, the integral form for a continuous distribution, and the far-field dipole potential. Field from potential: E = -dV/ds, the steepest-descent direction, E = -grad V, the partial-derivative components, and the scalar-first method. Equipotential surfaces and conductors: the definition and lines, perpendicularity to field lines, zero work along a surface, a conductor as an equipotential, grounding, and charge concentration at small radii of curvature. Applications: the Van de Graaff generator, xerography and the photoconductor, laser and ink-jet printers, and the electrostatic precipitator.
- Capacitance (Physics)Recall cards on capacitors and capacitance. Capacitors and capacitance: what a capacitor is and stores, its two-conductor construction, the definition C = Q/V, the farad and its name, the practical range, geometry dependence, the constant Q/V ratio, the parallel-plate result C = eps0*A/d, the permittivity of free space, the field E = sigma/eps0, and the spherical, isolated-sphere, and cylindrical capacitance formulas. Capacitors in series and parallel: the reciprocal-sum series rule, equal series charge, the smaller-than-smallest result, series voltage adding, the parallel sum rule, equal parallel voltage, the larger-than-largest result, parallel charge adding, and network reduction. Energy stored: field storage, the three energy forms U = 1/2 C V^2, U = Q^2/2C, U = 1/2 Q V, energy persisting after disconnection, the energy density u = 1/2 eps0 E^2, and the defibrillator. Capacitor with a dielectric: what a dielectric is, the dielectric constant kappa, kappa = 1 for vacuum and kappa > 1 otherwise, C = kappa*C_0, the constant-charge and voltage/energy drops on a disconnected capacitor, dielectric strength, and the stud finder. Molecular model of a dielectric: polar versus nonpolar molecules, alignment and induced dipoles, surface induced charge, the opposing induced field, E = E_0/kappa, and breakdown.
- Current and Resistance (Physics)Recall cards on electric current, resistance, and superconductors. Electrical current: current as the rate of charge flow, I = dQ/dt, the ampere and its name, the need for a complete circuit, conventional current, electron carriers in metals, carriers in ionic solutions, and drift velocity. Model of conduction in metals: the free-electron sea, the zig-zag drift path, signal speed versus drift speed, I = nqAv_d, current as a scalar, current density J as a vector, J = nqv_d, E = rho J, and why good electrical conductors conduct heat. Resistivity and resistance: resistivity rho, its reciprocal conductivity, the ohm-meter, conductor versus insulator versus semiconductor, R = V/I, R = rho L/A, the ohm, the temperature dependence rho = rho_0[1 + alpha(T - T_0)], and the temperature coefficient alpha. Ohm's law: V = IR, Ohm's experiment, its empirical nature, ohmic versus nonohmic devices, and the diode. Electrical energy and power: P = IV, P = I^2 R, P = V^2/R, the watt, resistive heating, E = Pt, and the kilowatt-hour. Superconductors: zero resistance below a critical temperature, Onnes's discovery, mercury, the Meissner effect, Type I and Type II, YBCO, BCS theory and Cooper pairs, persistent currents, MRI magnets, SQUIDs, and the Josephson effect.
- Direct-Current Circuits (Physics)Recall cards on direct-current circuits. Electromotive force: emf as work per unit charge, the symbol epsilon, the volt, energy conversion, terminal voltage, internal resistance r, V_terminal = emf - I r, I = emf/(R + r), and ideal versus real batteries. Resistors in series and parallel: the same current in series, R_S as a sum, the source voltage as a sum of drops, the same voltage in parallel, 1/R_P as a sum of reciprocals, branch currents summing to the total, and combination circuits. Kirchhoff's rules: junctions, the junction rule from charge conservation, the loop rule from energy conservation, and the sign conventions for resistors and emf sources. Electrical measuring instruments: the ammeter in series, the voltmeter in parallel, the galvanometer, converting it to an ammeter or voltmeter, and analog, digital, and ohmmeter designs. RC circuits: charging and discharging of a capacitor, the time constant tau = RC, the 63.2% and 36.8% marks, and a full capacitor as an open circuit. Household wiring and safety: thermal and shock hazards, short circuits, P = I^2 R_w, fuses and breakers, the live, neutral, and ground wires, grounding, and the GFCI.
- Magnetic Forces and Fields (Physics)Recall cards on magnetic forces and fields. Magnets and Earth's field: the two poles, attraction and repulsion, the absence of magnetic monopoles, Earth as a bar magnet, compass behavior, field reversals, and the historical discoveries of Oersted, Ampere, Arago, and Faraday. The magnetic field: its definition through the force on a moving charge, F = qv x B, F = qvB sin(theta), the tesla and gauss, the right-hand rule, and field lines. Motion of a charged particle: circular and helical paths, why the magnetic force does no work, r = mv/(qB), the period T = 2 pi m/(qB), pitch, magnetic bottles, and the Van Allen belts. Force on a current-carrying conductor: RHR-2, F = IL x B, F = BIL sin(theta), and the zero net force on a closed loop. Force and torque on a current loop: the magnetic dipole moment mu = NIA, tau = mu x B, tau = IAB sin(theta), the potential energy U = -mu . B, electric motors, and the commutator. The Hall effect: Hall's experiment, the Hall voltage, the force balance, drift speed, velocity selectors, and identifying charge carriers. Applications: the mass spectrometer and the cyclotron.
- Sources of Magnetic Fields (Physics)Recall cards on the sources of magnetic fields. The Biot-Savart law: the field of a current element, the permeability of free space, the right-hand rule for the direction, and the field of a circular arc and a full loop. The magnetic field of a thin straight wire: B = mu_0 I/(2 pi R), concentric circular field lines, and the right-hand rule. The force between two parallel currents: attraction and repulsion, the historical ampere definition, and the pinch effect. The magnetic field of a current loop: the magnetic dipole moment, the on-axis field, and the inverse-cube dipole falloff. Ampere's law: the line integral of B, the enclosed current, the Amperian loop, when to use it versus the Biot-Savart law, and the field inside and outside a thick wire. Solenoids and toroids: the uniform interior field of a solenoid, the zero exterior field, and the toroid field. Magnetism in matter: atomic dipole moments, paramagnetism, diamagnetism, ferromagnetism, magnetic domains, hysteresis, susceptibility, and permeability.
- Electromagnetic Induction (Physics)Recall cards on electromagnetic induction. Faraday's law: magnetic flux and the weber, the induced emf as the negative rate of change of flux, and the N-turn coil form. Lenz's law: the induced current opposes the flux change, the negative sign, the like-pole repulsion of an approaching magnet, and the energy-conservation basis. Motional emf: epsilon = Blv, the induced current and retarding force on a moving rod, and the mechanical-to-electrical power balance. Induced electric fields: the line-integral form of Faraday's law, the nonconservative character with no associated potential, and the field around a circular path. Eddy currents: magnetic damping, slotted plates, metal detectors, eddy-current braking, and induction cooktops. Electric generators and back emf: the rotating-coil emf, peak emf, motor-versus-generator energy conversion, and how back emf sets a motor's current. Applications: hard disk read heads, giant magnetoresistance, magnetic stripes, graphics tablets, regenerative braking, and transcranial magnetic stimulation.
- Inductance (Physics)Recall cards on inductance. Mutual inductance: the henry, the M = N Phi / I definition, its symmetry and geometry dependence, and the induced emf epsilon = -M dI/dt. Self-inductance: Phi = LI, the self-induced emf -L dI/dt, its Lenz's-law polarity, the inductor as a circuit element, and the solenoid formula. Energy in a magnetic field: U = (1/2) L I^2, the energy density B^2/(2 mu0), and inductor power. RL circuits: the asymptotic rise and decay of current, the time constant L/R, the 63% rule, and the initial and steady-state conditions. LC oscillations: omega = 1/sqrt(LC), the electric-to-magnetic energy exchange, the charge and current solutions and their 90-degree phase, and the mass-spring analogy. RLC series circuits: damped oscillations, the governing differential equation, and the underdamped, critically damped, and overdamped regimes.
- Alternating-Current Circuits (Physics)Recall cards on alternating-current circuits. AC sources: DC versus AC, the v = V0 sin(omega t) and i = I0 sin(omega t) forms, peak versus instantaneous notation, and US and European mains values. Simple AC circuits: the resistor in phase, the capacitor's current leading and the inductor's current lagging by pi/2, capacitive reactance XC = 1/(omega C), inductive reactance XL = omega L, their frequency dependence, and phasors. Series RLC circuits: impedance Z = sqrt(R^2 + (XL - XC)^2), the AC Ohm's law I0 = V0/Z, the phase angle, and the element voltages. Power: rms current and voltage, the average-power formulas, the power factor cos(phi), and why only resistors dissipate. Resonance: XL = XC, omega0 = 1/sqrt(LC), minimum impedance, maximum current and power, and the quality factor. Transformers: the voltage and current turns ratios, step-up and step-down, power conservation, and high-voltage transmission.
- Electromagnetic Waves (Physics)Recall cards on electromagnetic waves. Maxwell's equations: the displacement current that completes Ampere's law, the four laws (Gauss, Gauss for magnetism, Faraday, Ampere-Maxwell), how changing fields generate each other, the prediction of waves at the speed of light, and Hertz's confirmation. Plane waves: transverse fields perpendicular to each other and to propagation, E/B = c, the wave equation, c = 1/sqrt(epsilon0 mu0), and the E cross B direction. Energy: energy density, the Poynting vector, intensity, and the field amplitude relation E0 = c B0. Momentum and radiation pressure: p = U/c, absorber versus reflector pressure, comet tails, and light sails. The electromagnetic spectrum: c = f lambda, and radio, microwave, infrared, visible, ultraviolet, X-ray, and gamma-ray bands.
- The Nature of Light (Physics)Recall cards on the nature of light. The propagation of light: the speed of light in vacuum, its invariance for all observers, the index of refraction n = c/v, and the ray model. The law of reflection: angle of reflection equals angle of incidence, specular versus diffuse reflection, corner reflectors, and retroreflectors. Refraction and Snell's law: bending toward or away from the normal, and representative indices for air, water, and diamond. Total internal reflection: the critical angle theta_c = arcsin(n2/n1) and optical fibers. Dispersion: white light spread into a spectrum, wavelength-dependent index, prisms, and rainbows. Huygens's principle: wavelets, wave fronts, refraction, and diffraction. Polarization: Malus's law, polarizing filters, Brewster's angle, birefringence, optical activity, and liquid-crystal displays.
- Geometric Optics and Image Formation (Physics)Recall cards on geometric optics and image formation. Plane mirrors: same-size, upright, virtual images located as far behind the mirror as the object is in front, and the real-versus-virtual image distinction. Spherical mirrors: concave and convex geometry, center of curvature, vertex, optical axis, focal point, f = R/2, the mirror equation 1/d_o + 1/d_i = 1/f, magnification m = -d_i/d_o, and sign conventions. Images formed by refraction: apparent depth h_i = (n2/n1) h_o and the single-spherical-surface equation. Thin lenses: converging and diverging behavior, the thin-lens equation, the lensmaker's equation, ray tracing, and image types. The eye: cornea and lens, accommodation, near and far points, optical power in diopters, and correction of myopia and hyperopia. The camera, the simple magnifier and angular magnification, and compound microscopes and telescopes.
- Interference (Physics)Recall cards on the wave interference of light. Young's double-slit experiment: coherence versus incoherence, constructive and destructive interference, fringes, and the historical evidence for the wave nature of light. The mathematics of interference: path length difference delta-l = d sin(theta), bright fringes at d sin(theta) = m*lambda, dark fringes at d sin(theta) = (m + 1/2)*lambda, order m, and the fringe position y_m = m*lambda*D/d. Multiple-slit interference: principal maxima, the N minus 2 secondary maxima, secondary-maximum amplitude 1/N and intensity 1/N^2, and the diffraction grating. Interference in thin films: the 180-degree phase change on reflection off a higher-index medium, the in-film wavelength lambda_n = lambda/n, and the soap-film constructive and destructive conditions. The Michelson interferometer: the beam splitter, the fringe-shift relation 2*delta-d = m*lambda_0, the compensator plate, and its use in precision measurement.
- Diffraction (Physics)Recall cards on the diffraction of light. Single-slit diffraction: the bright central maximum and dimmer secondary maxima, the dark-fringe condition a sin(theta) = m*lambda, and why a narrower slit spreads the pattern. Intensity in single-slit diffraction: the phasor derivation, I = I0 (sin(beta)/beta)^2 with beta = (pi a sin(theta))/lambda, and the faint 0.045 and 0.016 secondary maxima. Double-slit diffraction as an interference pattern under a single-slit envelope, and missing orders. Diffraction gratings: d sin(theta) = m*lambda, sharp principal maxima, and spectroscopy. Circular apertures and resolution: the Rayleigh criterion theta = 1.22 lambda/D, microscope resolution x = 0.61 lambda/NA, and the diffraction limit. X-ray diffraction and Bragg's law m*lambda = 2d sin(theta). Holography: recording amplitude and phase by the interference of laser light.
- Relativity (Physics)Recall cards on special relativity. Einstein's two postulates: the laws of physics are the same in all inertial frames, and light travels at the same speed c in all inertial frames regardless of the motion of source or observer. Relativity of simultaneity. Time dilation Delta t = gamma * Delta tau, proper time, and the Lorentz factor gamma = 1/sqrt(1 - v^2/c^2). The twin paradox. Length contraction L = L0*sqrt(1 - v^2/c^2) along the direction of motion. The Lorentz transformation, the invariant spacetime interval, and light cones. Relativistic velocity addition. The relativistic Doppler effect, redshift, and blueshift. Relativistic momentum p = gamma*m*u. Relativistic energy E = gamma*m*c^2, rest energy E0 = m*c^2, kinetic energy K = (gamma - 1)*m*c^2, the energy-momentum relation E^2 = (pc)^2 + (mc^2)^2, and mass-energy equivalence.
- Photons and Matter Waves (Physics)Recall cards on the birth of quantum physics. Blackbody radiation, the Stefan-Boltzmann law P = sigma*A*T^4, Wien's displacement law, the ultraviolet catastrophe, and Planck's quantization E_n = n*h*f. The photoelectric effect and Einstein's photon explanation, the photoelectric equation K_max = h*f - phi, the work function, and the cutoff frequency. The Compton effect and the photon momentum p = h/lambda. Bohr's model of the hydrogen atom, the Rydberg formula, quantized angular momentum, the Bohr radius, and the energy levels E_n = -13.6 eV/n^2. De Broglie's matter waves lambda = h/p and the Davisson-Germer experiment. Wave-particle duality and Heisenberg's uncertainty principle Delta x * Delta p >= h-bar/2.
- Quantum Mechanics (Physics)Recall cards on nonrelativistic quantum mechanics. The wave function and the Born interpretation |Psi|^2 as a probability density, normalization, expectation values, and the position and momentum operators. The Heisenberg uncertainty principle in its position-momentum and energy-time forms. The time-dependent and time-independent Schrodinger equations, stationary states, and separation of variables. The quantum particle in a box with quantized energies E_n = n^2 pi^2 h-bar^2/(2mL^2) and zero-point energy. The quantum harmonic oscillator with evenly spaced levels E_n = (n + 1/2) h-bar omega. Quantum tunneling through potential barriers, the transmission probability, and applications from alpha decay to the scanning tunneling microscope.
- Atomic Structure (Physics)Recall cards on the quantum structure of atoms. The hydrogen atom and its three quantum numbers n, l, and m, the quantized energy E_n = -13.6 eV/n^2, orbital angular momentum L = sqrt(l(l+1)) h-bar, space quantization, and spectroscopic s, p, d, f notation. The orbital magnetic dipole moment, the Bohr magneton, and the Zeeman effect. Electron spin with s = 1/2, the Stern-Gerlach experiment, the Pauli exclusion principle and the building-up of the periodic table. Atomic spectra and selection rules, characteristic X-rays and Moseley's law, bremsstrahlung, and the physics of lasers including stimulated emission, population inversion, and gain media.
- Condensed Matter Physics (Physics)Recall cards on condensed matter physics. Molecular bonding by ionic, covalent, and van der Waals forces, the energetics of NaCl and H2 formation, and molecular rotational and vibrational spectra. Bonding in crystalline solids, the Madelung constant, and dissociation energy. The free electron model of metals, the Fermi energy, the Fermi factor, and the density of states. Band theory, valence and conduction bands, and the energy gaps that distinguish conductors, insulators, and semiconductors. Doping, n-type and p-type material, holes, the p-n junction, diodes, and transistors. Superconductivity, the Meissner effect, critical fields, Cooper pairs and BCS theory, and high-temperature superconductors.
- Nuclear Physics (Physics)Recall cards on nuclear physics. Properties of nuclei: protons, neutrons, nucleons, atomic and mass numbers, isotopes, the atomic mass unit, nuclear radius and density, and the strong nuclear force. Nuclear binding energy, the mass defect, binding energy per nucleon, and the stability of iron-56. Radioactive decay, the decay law and decay constant, half-life, activity, the becquerel and curie, and carbon-14 dating. Alpha, beta, and gamma decay with their changes in Z and A and their penetrating power. Nuclear fission, chain reactions, critical mass, and the liquid drop model. Nuclear fusion, the proton-proton chain in the Sun, and the deuterium-tritium reaction. Medical applications and biological effects: technetium-99m, PET imaging, the gray, the rad, relative biological effectiveness, and the sievert.
- Particle Physics and Cosmology (Physics)Recall cards on particle physics and cosmology. The four fundamental forces and their ranges and relative strengths. Fermions and bosons; the six quarks and their fractional charges; hadrons, mesons, and baryons; the six leptons; force carriers (photon, gluons, W and Z bosons, graviton) and the Higgs boson; antiparticles and annihilation. Conservation laws: baryon number, the three lepton numbers, strangeness, and neutrino oscillations. Quarks: spin, color charge, confinement, gluons, and the deep-inelastic-scattering evidence. Particle accelerators (Van de Graaff, linac, cyclotron, synchrotron, colliding beams, the LHC) and detectors. The Standard Model: electroweak theory, quantum electrodynamics, quantum chromodynamics, Feynman diagrams, virtual particles, and grand unified theories. Cosmology: Hubble's law, the Hubble constant, the Big Bang as expanding space, cosmological redshift, the age of the universe, the epochs of the early universe, Big Bang nucleosynthesis, the cosmic microwave background, and dark energy and dark matter.
- Introduction (Astronomy)Recall cards introducing astronomy. What astronomy studies and where the elements of life were made. The nature of science: hypotheses, observational versus historical science, and peer review. The universality of physical laws. Numbers in astronomy: scientific notation, the speed of light, and the light-year. Light travel time and looking back in time. A tour of the solar system: planets, stars, the astronomical unit, and the sizes and distances of the Earth, Moon, and Sun. The Milky Way and the large-scale universe: galaxies, constellations, the Local Group, Andromeda, superclusters, and quasars. The universe of the very small: atoms, molecules, elements, and the density of matter in air, interstellar, and intergalactic space. Carl Sagan's cosmic calendar.
- Observing the Sky: The Birth of Astronomy (Astronomy)Recall cards on how humans learned to read and understand the sky. The celestial sphere and its landmarks: zenith, horizon, celestial poles and equator, and how the pole's altitude reveals your latitude. The ecliptic, the 88 constellations, asterisms, and the zodiac. Ancient astronomy: Eratosthenes measuring the Earth, Hipparchus and his star catalog, magnitudes, and precession, Ptolemy's geocentric model and the Almagest, Stonehenge, and the Maya. Astrology versus astronomy: horoscopes, the twelve signs, and why astrology has no scientific support. The birth of modern astronomy: Copernicus and the heliocentric model, and Galileo's telescopic discoveries of the phases of Venus, the moons of Jupiter, the stars of the Milky Way, and the mountains of the Moon.
- Orbits and Gravity (Astronomy)Recall cards on how the motions of the planets were measured and finally explained. Tycho Brahe's 20 years of observations and Kepler's three laws of planetary motion: elliptical orbits, foci and eccentricity, the law of equal areas, and P squared = a cubed. Newton's synthesis: his three laws of motion, momentum, mass, velocity, acceleration, density, and angular momentum. The universal law of gravitation, the inverse-square force, the gravitational constant, and Newton's mass-bearing form of Kepler's third law. Orbits in the solar system: perihelion and aphelion, the eight planets, the asteroid belt, and comets. Satellites and spacecraft: circular and escape speeds, orbital decay, and gravity assists (Voyager 2). Finally, gravity with many bodies: perturbations and the prediction and discovery of Neptune that confirmed Newton's laws.
- Earth, Moon, and Sky (Astronomy)Recall cards on how Earth's motions define the sky and our measures of time. The celestial sphere: great circles, meridians, longitude and latitude, the celestial equator and poles, declination and right ascension, and Foucault's pendulum. The seasons: Earth's 23.5-degree axial tilt, solstices and equinoxes, and the tropics and polar circles. Keeping time: sidereal versus solar days, apparent and mean solar time, standard time zones, daylight saving, and the International Date Line. The calendar: the tropical year and synodic month, the Julian and Gregorian reforms, and leap-year rules. Phases and motions of the Moon: the sidereal and synodic months, phase rise and set times, and synchronous rotation. Ocean tides: the tidal force, two bulges, spring and neap tides, and tidal friction. Finally eclipses of the Sun and Moon: umbra and penumbra, annular and total eclipses, and why they do not happen every month.
- Radiation and Spectra (Astronomy)Recall cards on light and how it reveals the nature of matter across the universe. The behavior of light: Maxwell's electromagnetic theory, wavelength and frequency, the speed of light, the photon and wave-particle duality, and the inverse square law of brightness. The electromagnetic spectrum: gamma rays, X-rays, ultraviolet, visible, infrared, microwaves, and radio waves, plus Wien's law and the Stefan-Boltzmann law for blackbody radiation. Spectroscopy: Newton's prism, dispersion, continuous, absorption, and emission spectra, Fraunhofer lines, and Kirchhoff's identification of elements. The structure of the atom: electrons, protons, and neutrons, the nucleus, isotopes, the Bohr model, and Planck's constant. Formation of spectral lines: ground and excited states, excitation and emission, the Lyman, Balmer, and Paschen series of hydrogen, ionization, and recombination. Finally the Doppler effect: blueshift and redshift, radial velocity, and the Doppler formula.
- Astronomical Instruments (Astronomy)Recall cards on the telescopes and detectors astronomers use to study the universe. Telescopes: their light-gathering and focusing functions, aperture and collecting area, refractors versus reflectors, chromatic aberration, the Newtonian and Cassegrain focus, and the history from Lippershey and Galileo to Newton's first reflector and the great refractors. Telescopes today: the 8-to-10-meter giants (Keck, Gran Telescopio Canarias, VLT, Subaru, Gemini, Hale), segmented mirrors, high and dark sites, and active and adaptive optics. Detectors: photographic plates, CCDs, imaging versus spectroscopy, diffraction gratings, and cooled infrared detectors. Radio telescopes: Jansky and Reber, dishes and receivers, Green Bank, Arecibo, and FAST, and interferometry from the VLA and ALMA to the VLBA. Space observatories: Hubble, IRAS, Spitzer, JWST, SOFIA, Chandra, and Fermi. And the future giants: the ELT, TMT, GMT, Vera Rubin Observatory, and the Cherenkov Telescope Array.
- The Solar System: An Overview (Astronomy)Recall cards introducing the solar system as a whole. Its inventory: the Sun, the eight planets, their moons and rings, and debris such as asteroids, comets, and dust, formed together about 4.5 billion years ago. The layout: the Sun holding 99.8 percent of the mass, the terrestrial versus jovian planets, distances in astronomical units and orbital periods, densities, and rotations. The smaller bodies: trans-Neptunian objects, the five dwarf planets, moons from the Galilean satellites to Titan and Triton, ring systems, asteroids, comets, meteors, and meteorites. Composition and structure: the hydrogen-rich giants, silicate-and-iron terrestrials, differentiation, and how surface temperature falls with distance. Dating surfaces by crater counts and by radioactive decay, with the major parent-daughter isotope pairs and their half-lives. And the origin of the solar system from a spinning solar nebula of gas and dust.
- Earth as a Planet (Astronomy)Recall cards studying Earth as one of the terrestrial planets. Its bulk properties: diameter, mass, record-high density, and escape velocity. Its layered interior built by differentiation: the basaltic oceanic and granitic continental crust, the deep mantle, the iron core, and the magnetic field and magnetosphere the liquid core produces. Its restless crust: igneous, sedimentary, and metamorphic rock, roughly a dozen tectonic plates driven by mantle convection, seafloor spreading, subduction, faults, continental drift, and hot spots. Its atmosphere: the nitrogen-oxygen-argon mix, sea-level pressure, the troposphere, stratosphere, and ionosphere, the ozone layer, and weather versus climate. The coevolution of life and air: the oldest rocks, stromatolites, the rise of oxygen, and present-day carbon dioxide and the greenhouse effect. And the cosmic impacts that have shaped Earth, from Tunguska and Chelyabinsk to Meteor Crater and the Chicxulub impact that ended the age of the dinosaurs.
- Cratered Worlds: The Moon and Mercury (Astronomy)Recall cards studying the Moon and Mercury, the airless, heavily cratered worlds closest to home. The Moon's bulk properties: its diameter, mass, surface gravity, escape velocity, low density, and synchronous rotation, and why it holds no atmosphere. Its two terrains: the dark basaltic maria that flooded impact basins, the bright, ancient, heavily cratered highlands of anorthosite, the regolith, and its extreme day and night temperatures. The physics of impact cratering: impact speeds, the nuclear-scale blast, crater and ejecta sizes, bright rays, secondary craters, and how often craters of a given size form. The competing ideas for the Moon's origin, from the fission, sister, and capture hypotheses to the leading giant impact hypothesis. And Mercury: its eccentric orbit, huge iron core, 3-to-2 spin-orbit resonance, temperature extremes, shrinkage scarps, the Caloris basin, polar ice, and the Mariner 10 and MESSENGER missions that mapped it.
- Earthlike Planets: Venus and Mars (Astronomy)Recall cards comparing Venus and Mars, Earth's two nearest planetary neighbors. The bulk and orbital data of each world: distance from the Sun, orbital period, diameter, mass, density, surface gravity, escape velocity, rotation, and surface conditions. The geology of Venus: its lowland lava plains, the absence of plate tectonics, the Aphrodite and Ishtar highlands, the Maxwell Mountains, its shield volcanoes and pancake domes, and how Magellan's radar and the Venera landers explored it. The crushing 90-bar, 96-percent carbon-dioxide atmosphere of Venus, its sulfuric-acid clouds, and the runaway greenhouse effect that makes it the hottest planet. The geology of Mars: Olympus Mons, the Valles Marineris canyons, the Tharsis bulge, its cratered southern highlands, and the Mariner and Viking missions. The evidence for water and life on Mars: its polar caps, runoff and outflow channels, recurring slope lineae, subsurface ice, and ancient lakebeds. And why three planets that began alike diverged into such different worlds.
- The Giant Planets (Astronomy)Recall cards on the four giant planets of the outer solar system: Jupiter, Saturn, Uranus, and Neptune. The composition of the outer solar system and the distinction between the gas giants (Jupiter and Saturn) and the ice giants (Uranus and Neptune). The robotic missions that explored them: the Pioneers, the two Voyagers and their Grand Tour, Galileo and its atmospheric probe at Jupiter, Cassini and the Titan landing at Saturn, and Juno's polar orbit. The bulk properties of each planet: orbital period, diameter, mass, density, rotation, and axial tilt, including Uranus tipped on its side. Their interiors of liquid metallic hydrogen, rock-and-ice cores, internal heat sources, and strong tilted magnetic fields. And their atmospheres: the hydrogen-helium composition, the ammonia and methane cloud decks, the belts and zones, the ferocious jet streams, and the long-lived storms such as Jupiter's Great Red Spot and Neptune's Great Dark Spot.
- Rings, Moons, and Pluto (Astronomy)Recall cards on the moon and ring systems of the giant planets, and on the dwarf planet Pluto. The four Galilean moons of Jupiter: heavily cratered Callisto, giant Ganymede, ocean-bearing Europa, and volcanic Io, whose eruptions are driven by tidal heating. Saturn's moons, including Titan with its thick nitrogen atmosphere and hydrocarbon lakes, and Enceladus with its water geysers and subsurface ocean. Neptune's captured moon Triton, the coldest world yet visited, with its nitrogen geysers. Pluto and its large moon Charon, in a double tidal lock, explored by New Horizons in 2015. And the planetary ring systems: the bright, broad water-ice rings of Saturn with the Cassini Division, the dark narrow rings of Uranus and Neptune, and how orbital resonances and shepherd moons sculpt them.
- Comets and Asteroids (Astronomy)Recall cards on the small bodies of the solar system: asteroids and comets. The asteroid belt between Mars and Jupiter, the largest asteroids Ceres, Pallas, and Vesta, and the C-type, S-type, and M-type compositional classes. The spacecraft that visited and sampled asteroids: Galileo, NEAR-Shoemaker, Hayabusa, OSIRIS-REx, Dawn, and Lucy, plus the interstellar visitor 'Oumuamua. Near-Earth objects and planetary defense: the Tunguska and Chelyabinsk airbursts, the Spaceguard Survey, and the DART and Hera missions. The anatomy of a comet, its nucleus, coma, and tails, Fred Whipple's dirty snowball model, and famous comets such as Halley and 67P Churyumov-Gerasimenko explored by Rosetta and Philae. And the reservoirs that supply comets: the distant Oort cloud of long-period comets and the Kuiper belt beyond Neptune that feeds the short-period comets.
- Cosmic Samples and the Origin of the Solar System (Astronomy)Recall cards on the cosmic samples that reach Earth and what they reveal about how the solar system formed. Meteors, the shooting stars produced when tiny particles burn up in the atmosphere, and the meteor showers Earth meets when it crosses a comet's debris stream, from the Perseids to the Leonids. Meteorites, the fragments that survive to the ground: the iron, stony, and stony-iron classes, primitive versus differentiated bodies, and the amino acids in the Murchison meteorite that date the solar system to about 4.56 billion years. The solar nebula model of formation: a collapsing spinning disk, the condensation sequence that split the rocky inner planets from the icy giants, planetesimal accretion, and differentiation. What other planetary systems teach us, found by the Doppler and transit methods and by Kepler: super-Earths, hot Jupiters, and planetary migration. And the long-term evolution of worlds, where size governs how long a planet stays geologically alive, from the dead Moon to plate-tectonic Earth and Olympus Mons on Mars.
- The Sun: A Garden-Variety Star (Astronomy)Recall cards on the Sun, the ordinary star at the center of our solar system, and the activity that plays across its surface. Its structure and composition: a ball of mostly hydrogen and helium a million kilometers wide, from the 15-million-degree core out through the convective zone to the visible photosphere, the thin chromosphere, and the tenuous but million-degree corona that launches the solar wind. The solar cycle: sunspots and their umbra and penumbra, the roughly 11-year rhythm of sunspot maxima, differential rotation, the Zeeman effect that maps magnetic fields, and the 22-year magnetic cycle driven by the solar dynamo. Solar activity above the photosphere: plages, prominences, flares, coronal mass ejections, and the active regions where strong magnetic fields tie them together. And space weather, the way particles and radiation from the Sun disturb Earth's magnetosphere, from the Carrington Event of 1859 and the 1989 Quebec blackout to the Maunder Minimum.
- The Sun: A Nuclear Powerhouse (Astronomy)Recall cards on how the Sun actually shines. The nineteenth-century puzzle of the Sun's energy source: chemical burning would last only a few thousand years, and even Kelvin and Helmholtz's gravitational contraction could power it for only about 100 million years, far short of Earth's geological age. The answer came from Einstein's E = mc^2 and nuclear fusion: deep in the core, above about 12 million K, the proton-proton chain fuses roughly 600 million tons of hydrogen into helium each second, converting about 4 million tons of matter into pure energy. The solar interior in theory: hydrostatic equilibrium, the radiative and convective zones, and the hundreds of thousands of years a photon takes to escape while a neutrino leaves in seconds. And the observations that confirm it: the solar neutrino problem, neutrino oscillation, the Davis and Sudbury experiments, and helioseismology.
- Analyzing Starlight (Astronomy)Recall cards on how astronomers read a star's light. Brightness: the difference between luminosity (total energy emitted per second) and apparent brightness (energy reaching us), the inverse-square dimming with distance, and Hipparchus's magnitude scale on which brighter means a smaller number and five magnitudes span a factor of 100. Color: a star's surface temperature sets its color, from over 40,000 K blue-white down to about 2,000 K red, quantified by the UBV color index. Spectra: the temperature-ordered OBAFGKM (plus L, T, Y) classes, their spectral-line signatures, brown dwarfs, and Annie Jump Cannon. And what spectra reveal: composition (about three-quarters hydrogen), radial velocity from the Doppler shift, proper motion across the sky, and rotation and pressure read from the width of the lines.
- Science GeneralScience and nature, including biology, chemistry, physics, and the natural world
- ComputersComputer science, programming, hardware, software, and technology
- Chemical ElementsLearn the periodic table - match symbols to element names
- MathematicsAlgebra, geometry, calculus, and number theory