The Gale encyclopedia of science
(eBook)

Aardvark -- Abacus -- Abrasives -- Abscess -- Absolute zero -- Abyssal plain -- Acceleration -- Accelerators -- Accretion disk -- Accuracy -- Acetic acid -- Acetone -- Acetylcholine -- Acetylsalicylic acid -- Acid rain -- Acids and bases -- Acne -- Acorn worm -- Acoustics -- Actinides -- Action potential -- Activated complex -- Active galactic nuclei -- Acupressure -- Acupuncture -- ADA (adenosine deaminase) deficiency -- Adaptation -- Addiction -- Addison's disease -- Addition -- Adenosine diphosphate -- Adenosine triphosphate -- Adhesive -- Adipocere -- Adrenals -- Aerobic -- Aerodynamics -- Aerosols -- Aerospace engineering -- Aflatoxin -- Africa -- Agent Orange -- Aging and death -- Agouti -- Agribusiness -- Agricultural machines -- Agrochemicals -- Agronomy -- AIDS -- AIDS therapies and vaccines -- Air masses and fronts -- Air pollution -- Aircraft -- Airship -- Albatross -- Albedo -- Albinism -- Alchemy -- Alcohol -- Alcoholism -- Aldehydes -- Alfalfa, genetically engineered -- Algae -- Algal blooms -- Algebra -- Algorithm -- Alkali metals -- Alkaline earth metals -- Alkaloid -- Alkyl group -- Alleles -- Allergy -- Allotrope -- Allotype -- Alloy -- Alluvial systems -- Alpha particle -- Alternate light source analysis -- Alternative and renewable energy -- Alternative energy sources -- Alternative medicine -- Altruism -- Aluminum -- Aluminum hydroxide -- Alzheimer's disease -- Amaranth family (Amaranthaceae) -- Amaryllis family (Amaryllidaceae) -- American Standard Code for Information Interchange -- Ames test -- Amicable numbers -- Amides -- Amino acid -- Ammonia -- Ammonification -- Amnesia -- Amniocentesis -- Amoeba -- Amphetamines -- Amphibians -- Amplifier -- Amputation -- Anabolism -- Anaerobic -- Analemma -- Analgesia -- Analog signals and digital signals -- Analytic geometry -- Anaphylaxis -- Anatomy -- Anatomy, comparative -- Anchovy -- Anemia -- Anesthesia -- Aneurism -- Angelfish -- Angiography -- Angiosperm -- Angle -- Anglerfish -- Animal -- Animal breeding -- Animal cancer tests -- Animal cloning -- Animal testing -- Anion -- Anode -- Anoles -- Antarctica -- Antbirds and gnat-eaters -- Anteaters -- Antelopes and gazelles -- Antenna -- Anthrax -- Anthropocentrism -- Anthropogenic -- Anthropometry -- Antibacterial drugs -- Antibiotic resistance -- Antibiotics -- Antibody and antigen -- Anticoagulants -- Anticonvulsants -- Antidepressant drugs -- Antihelmintics -- Antihistamines -- Anti-inflammatory agents -- Antimatter -- Antimetabolites -- Antioxidants -- Antiparticle -- Antipsychotic drugs -- Antisepsis -- Antiviral drugs -- Antlions -- Ant-pipits -- Ants -- Anxiety -- Apes -- Apgar score -- Aphasia -- Aphids -- Approximation -- Apraxia -- Aquaculture -- Aqueduct -- Aquifer -- Arachnids -- Arapaima -- Arc -- Arc lamp -- Archaebacteria -- Archaeoastronomy -- Archaeogenetics -- Archaeological mapping -- Archaeological sites -- Archaeology -- Archaeometallurgy -- Archaeometry -- Arctic region -- Arithmetic -- Armadillos -- Arrow worms -- Arrowgrass -- Arrowroot -- Arsenic -- Arteries -- Arteriosclerosis -- Arthritis -- Arthropods -- Arthroscopic surgery -- Artifacts and artifact classification -- Artificial fibers -- Artificial heart and heart valve -- Artificial intelligence -- Artificial vision -- Arum family (Araceae) -- Asbestos -- Asexual reproduction -- Asia -- Assembly line -- Asses -- Associative property -- Asteraceae -- Asteroid 2002 AA29 -- Asthenosphere -- Asthma -- Astrobiology -- Astroblemes -- Astrolabe -- Astrometry -- Astronomical unit -- Astronomy -- Astrophysics -- Atmosphere, composition and structure -- Atmosphere observation -- Atmospheric chemistry -- Atmospheric circulation -- Atmospheric feedback factors -- Atmospheric optical phenomena -- Atmospheric pressure -- Atmospheric temperature -- Atomic clock -- Atomic models -- Atomic number -- Atomic spectroscopy -- Atomic theory -- Atomic weight -- Atoms -- Attention-deficit/hyperactivity disorder (ADHD) -- Augmented reality -- Auks -- Australia -- Autism -- Autoimmune disorders -- Automatic pilot -- Automation -- Automobiles -- Autopsy -- Autotroph -- Avogadro's number -- Aye-ayes -- Babblers -- Baboons -- Bacteria -- Bacterial blights -- Bacteriophage -- Badgers -- Ball bearing -- Ballistic missiles -- Ballistics -- Balloon -- Banana -- Bandicoots -- Bar code -- Barberry -- Barbets -- Barbiturates -- Bariatrics -- Barium -- Barium sulfate -- Bark -- Barley -- Barnacles -- Barometer -- Barracuda -- Barrier islands -- Basin -- Bass -- Basswood -- Bathymetric maps -- Bathysphere -- Bats -- Battery -- Beach nourishment -- Beardworms -- Bears -- Beavers -- Bedrock -- Beech family (Fagaceae) -- Bee-eaters -- Bees -- Beetles -- Beets -- Begonia -- Behavior -- Bennettites -- Benzene -- Benzoic acid -- Bernoulli's principle -- Beta-blockers -- Big bang theory -- Binary star -- Bindle paper -- Binocular -- Binomial theorem -- Bioaccumulation -- Bioassay -- Biochemical oxygen demand -- Biochemistry -- Biodegradable substances -- Biodegradation -- Biodetectors -- Biodiversity -- Bioenergy -- Biofeedback -- Biofilms -- Bio-flips -- Biofuels -- Bioinformatics and computational biology -- Biological and biomimetic systems -- Biological and chemical weapons -- Biological community -- Biological rhythms -- Biological warfare -- Biology -- Bioluminescence -- Biomagnification -- Biomass -- Biome -- Biomedical engineering -- Biometrics -- Biophysics -- Bioremediation -- Biosphere -- Biosphere Project -- Biotechnology -- Bioterrorism -- Bipolar disorder -- Birch family (Betulaceae) -- Birds -- Birds of paradise -- Birds of prey -- Birth -- Birth defects -- Bison -- Bitterns -- Bivalves -- BL Lacertae object -- Black hole -- Black hole collisions -- Blackbirds -- Blackbody radiation -- Bleach -- Blennies -- Blindness and visual impairments -- Blindsnakes -- Blockchain technology -- Blood -- Blood gas analysis -- Blood supply -- Bloodstain evidence -- Blotting analysis -- Bluebirds -- Boarfish -- Boas -- Bohr model -- Boiling point -- Bond energy -- Bony fish -- Boobies and gannets -- Boolean algebra -- Boric acid -- Botany -- Botulism -- Bowen's reaction series -- Bowerbirds -- Bowfin -- Boxfish -- Brachiopods -- Brackish -- Brain -- Breathalyzer® -- Brewing -- Brick -- Bridges -- Bristletails -- Brittle star -- Bromeliad family (Bromeliaceae) -- Bronchitis -- Brown dwarf -- Brownian motion -- Brucellosis -- Bryophyte -- Bubonic plague -- Buckminsterfullerene -- Buckthorn --

Buckwheat -- Buds and budding -- Buffer -- Building design/architecture -- Bulbuls -- Bunsen burner -- Buoyancy, principle of -- Buret -- Burn -- Bustards -- Buttercup -- Butterflies -- Butterfly fish -- Butyl group -- Butylated hydroxyanisole -- Butylated hydroxytoluene -- Buzzards -- Cactus -- CAD/CAM/CIM -- Caddisflies -- Caecilians -- Caffeine -- Caisson -- Calcium -- Calcium carbonate -- Calcium oxide -- Calcium propionate -- Calcium sulfate -- Calculator -- Calculus -- Calendars -- Calibration -- Caliper -- Calorie -- Calorimetry -- Camels -- Canal -- Cancel -- Cancer -- Canines -- Cannabidiol (CBD) -- Cantilever -- Capacitance -- Capacitor -- Capillaries -- Capillary action -- Caprimulgids -- Captive breeding and reintroduction -- Capuchins -- Capybaras -- Carbohydrate -- Carbon -- Carbon cycle -- Carbon dioxide -- Carbon footprint -- Carbon monoxide -- Carbon sink -- Carbon tetrachloride -- Carbonyl group -- Carboxyl group -- Carboxylic acids -- Carcinogen -- Cardiac cycle -- Cardinal number -- Cardinals and grosbeaks -- Caribou -- Carnivore -- Carnivorous plants -- Carp -- Carpal tunnel syndrome -- Carrier (genetics) -- Carrot family (Apiaceae) -- Carrying capacity -- Cartesian coordinate plane -- Cartilaginous fish -- Cartography -- Cashew family (Anacardiaceae) -- Cassini spacecraft -- Catabolism -- Catalyst and catalysis -- Catastrophism -- Catfish -- Catheters -- Cathode -- Cathode ray tube -- Cation -- Cats -- Cattails -- Cattle family (Bovidae) -- Cauterization -- Cave -- Cave fish -- Celestial coordinates -- Celestial mechanics -- Celestial sphere: The apparent motions of the Sun, Moon, planets, and stars -- Cell -- Cell death -- Cell division -- Cell, electrochemical -- Cell membrane transport -- Cell staining -- Cellular respiration -- Cellular telephone -- Cellulose -- Centipedes -- Centrifuge -- Ceramics -- Cerenkov effect -- Cetaceans -- Chachalacas -- Chameleons -- Chaos -- Charge-coupled device -- Chelate -- Chemical bond -- Chemical evolution -- Chemical oxygen demand -- Chemical reactions -- Chemical warfare -- Chemistry -- Chemoreception -- Chestnut -- Chickenpox -- Childhood diseases -- Chimaeras -- Chimpanzees -- Chinchilla -- Chipmunks -- Chi-square test -- Chitons -- Chlordane -- Chlorinated hydrocarbons -- Chlorination -- Chlorine -- Chlorofluorocarbons (CFCs) -- Chloroform -- Chlorophyll -- Chloroplast -- Cholera -- Cholesterol -- Chordates -- Chorionic villus sampling (CVS) -- Chromatin -- Chromatography -- Chromosomal abnormalities -- Chromosome -- Chromosome mapping -- Cicadas -- Cigarette smoke -- Circadian cycle and rhythm -- Circle -- Circulatory system -- Circumscribed and inscribed -- Cirrhosis -- Citric acid -- Citrus trees -- Civets -- Civil engineering -- Cladistics -- Clear-cutting -- Climate change -- Climate change impacts in Africa -- Climate change impacts in Asia -- Climate change impacts in Australia and New Zealand -- Climate change impacts in Europe -- Climate change impacts in North America -- Climate change impacts in small island nations -- Climate change impacts in South America -- Climax (ecological) -- Clingfish -- Clipper chip -- Clone and cloning -- Closed curves -- Closure property -- Cloud computing -- Clouds -- Club mosses -- Coal -- Coast and beach -- Coati -- Coca -- Cocaine -- Cockatoo -- Cockroaches -- Codeine -- Codfish -- Codon -- Coefficient -- Coelacanth -- Coffee plant -- Cogeneration -- Cognition -- Cold, common -- Collagen -- Colloid -- Colobus monkey -- Color -- Color blindness -- Colugo -- Coma -- Combinatorics -- Combustion -- Comet Hale-Bopp -- Comets -- Commensalism -- Communications technology -- Community ecology -- Commutative property -- Compact disc -- Competition -- Complementary DNA -- Complex -- Complex numbers -- Composite materials -- Composting -- Compound, chemical -- Compton effect -- Compulsion -- Computer, analog -- Computer, digital -- Computer hardware security -- Computer keystroke recorder -- Computer languages -- Computer memory, physical and virtual memory -- Computer modeling -- Computer software -- Computer software security -- Computer virus -- Computerized axial tomography -- Concentration -- Concrete -- Conditioning -- Condors -- Congenital -- Congruence (triangle) -- Conic sections -- Conifer -- Connective tissue -- Conservation -- Conservation laws -- Constellation -- Constructions -- Contaminated soil -- Contamination -- Continent -- Continental drift -- Continental margin -- Continental shelf -- Continuity -- Contour plowing -- Contraception -- Convection -- Coordination compound -- Copepods -- Copper -- Coral and coral reef -- Coral bleaching -- Coriolis effect -- Cork -- Corm -- Cormorants -- Corn (maize) -- Coronal ejections and magnetic storms -- Correlation (geology) -- Correlation (mathematics) -- Corrosion -- Cosmic background radiation -- Cosmic ray -- Cosmology -- Cotingas -- Cotton -- Coulomb -- Countable -- Coursers and pratincoles -- Courtship -- COVID-19 global pandemic -- Coypu -- Crab -- Crane -- Cranes -- Crayfish -- Crestfish -- Creutzfeldt-Jakob disease -- Crickets -- Crime scene investigation -- Crime scene reconstruction -- Critical habitat -- Crocodiles -- Crop rotation -- Crops -- Cross multiply -- Cross-section -- Crows and jays -- Crustacea -- Cryobiology -- Cryogenics -- Cryosphere -- Cryptography, encryption, and number theory -- Crystal -- Cubic equations -- Cuckoos -- Cultural geography -- Curare -- Curlews -- Currents -- Curve -- Cushing syndrome -- Cuttlefish -- Cybernetics -- Cybersecurity -- Cycads -- Cyclamate -- Cyclone and anticyclone -- Cyclosporine -- Cyclotron -- Cystic fibrosis -- Cytochrome -- Cytology -- Dams -- Damselflies -- Dark energy -- Dark matter -- Data mining -- Dating techniques -- DDT -- Deafness and inherited hearing loss -- Decimal fraction -- Decomposition -- Decontamination methods -- Decryption -- Deer -- Deer mouse -- Deforestation -- Degree -- Dehydroepiandrosterone (DHEA) -- Delta -- Dementia -- Dendrochronology -- Dengue fever -- Denitrification -- Density -- Dentistry -- Deoxyribonucleic acid (DNA) -- Deposit -- Depression -- Depth perception -- Derivative -- Desalination -- Desert -- Desertification -- Determinants -- Deuterium -- Developmental processes -- Dew point -- Diabetes mellitus -- Diagnosis -- Dialysis -- Diamond -- Diatoms -- Dielectric materials -- Diesel engine -- Diethylstilbestrol (DES) -- Diffraction -- Diffraction grating -- Diffusion -- Digestive system -- Digital recording -- Digitalis -- Dik-diks -- Dinosaur -- Diode -- Dioxin -- Diphtheria -- Dipole -- Direct variation -- Disease -- Dissociation -- Distance -- Distillation -- Distributive property -- Disturbance, ecological -- Diurnal cycles -- Division -- DNA databanks -- DNA fingerprinting -- DNA recognition -- instruments -- DNA replication -- DNA synthesis -- DNA technology -- DNA vaccine -- Dobsonflies -- Dogwood tree -- Domain -- Donkeys -- Dopamine -- Doppler effect -- Dories -- Dormouse -- Dosimetry -- Double helix -- Double-blind study -- Down syndrome -- Dragonflies -- Drift net -- Drones and unmanned aircraft -- Drongos -- Drosophila melanogaster -- Drought -- Ducks -- Duckweed -- Duikers -- Dune -- Duplication of the cube -- Dust devil -- DVD -- Dwarf antelopes -- Dyes and pigments --

Dysentery -- Dyslexia -- Dysplasia -- Dystrophinopathies -- e (number) -- Eagles -- Ear -- Earth -- Earth Challenge Prize -- Earth science -- Earthquake -- Earthquake and tsunami in Japan (2011) -- Earthquake in Mexico (2017) -- Earthquake in Nepal -- Earth's geologic history -- Earth's interior -- Earth's magnetic field -- Earth's rotation -- Earwigs -- Eating disorders -- Ebola virus -- Ebony -- Echiuroid worms -- Echolocation -- Eclipse -- Ecological economics -- Ecological integrity -- Ecological monitoring -- Ecological productivity -- Ecological pyramids -- Ecology -- Economic geography -- Ecosystem -- Ecotone -- Ecotourism -- Edema -- Eel grass -- Einstein-Podolsky-Rosen paradox -- El Ni̜o and La Nią -- Eland -- Elapid snakes -- Elasticity -- Electric arc -- Electric charge -- Electric circuit -- Electric conductor -- Electric current -- Electric motors -- Electric vehicles -- Electrical conductivity -- Electrical engineering -- Electrical power supply -- Electrical resistance -- Electricity -- Electrocardiogram (ECG) -- Electroencephalogram (EEG) -- Electrolysis -- Electrolyte -- Electromagnetic field -- Electromagnetic induction -- Electromagnetic pulse -- Electromagnetic spectrum -- Electromagnetism -- Electromotive force -- Electron -- Electron cloud -- Electronic control device (ECD) -- Electronics -- Electronics waste -- Electrophoresis -- Electrostatic devices -- Element, chemical -- Element, families of -- Element, transuranium -- Elements, formation of -- Elephant -- Elephant shrews -- Elephant snout fish -- Elephantiasis -- Elevator -- Ellipse -- Elm -- Embiids -- Embolism -- Embryo and embryonic development -- Embryo transfer -- Embryology -- Emission -- Emphysema -- Emulsion -- Encephalitis -- Endangered species -- Endemic -- Endocrine system -- Endoprocta -- Endoscopy -- Endothermic -- Energy -- Energy budgets -- Energy efficiency -- Energy transfer -- Engineering -- Engraving and etching -- Enhanced greenhouse effect -- Enterobacteria -- Entropy -- Environmental ethics -- Environmental impact statement -- Enzymatic engineering -- Enzyme -- Epidemic -- Epidemiology -- Epigenetics -- Epilepsy -- Episomes -- Epstein-Barr virus -- Equation, chemical -- Equilibrium, chemical -- Equinox -- Erosion -- Error -- Escherichia coli -- Ester -- Esterification -- Ethanol -- Ether -- Ethnoarchaeology -- Ethnobotany -- Ethyl group -- Ethylene glycol -- Ethylenediaminetetra-acetic acid -- Etiology -- Eubacteria -- Eugenics -- Eukaryotae -- Europe -- Eutrophication -- Evaporation -- Evapotranspiration -- Even and odd -- Event horizon -- Evolution -- Evolution, convergent -- Evolution, divergent -- Evolution, evidence of -- Evolution, parallel -- Evolutionary change, rate of -- Evolutionary mechanisms -- Excavation methods -- Exclusion principle, Pauli -- Excretory system -- Exercise -- Exocrine glands -- Explosives -- Exponent -- Extinction -- Extrasolar planets -- Extreme weather -- Eye -- Facial recognition -- Factor -- Factorial -- Falcons -- Faraday effect -- Fat -- Fat substitutes -- Fatty acids -- Fault -- Fauna -- Fax machine -- Feather stars -- Fermentation -- Ferns -- Ferrets -- Fertilization -- Fertilizers -- Fetal alcohol syndrome -- Feynman diagrams -- Fiber optics -- Fibonacci sequence -- Field -- Figurative numbers -- Filtration -- Finches -- Firs -- Fish -- 5G technology -- Flagella -- Flame analysis -- Flamingos -- Flatfish -- Flatworms -- Flavonoids -- Flax -- Fleas -- Flies -- Flightless birds -- Flooding -- Flora -- Flower -- Fluid dynamics -- Fluid mechanics -- Fluorescence -- Fluorescence in situ hybridization (FISH) -- Fluorescent light -- Fluoridation -- Flying fish -- Focused ion beam (FIB) -- Fog -- Fold -- Food irradiation -- Food poisoning -- Food preservation -- Food pyramid -- Food web/chain -- Foot and mouth disease -- Force -- Forensic genealogy -- Forensic science -- Forestry -- Forests -- Formula, chemical -- Formula, structural -- Fossa -- Fossil and fossilization -- Fossil fuels -- Fracking -- Fractal -- Fraction, common -- Fraunhofer lines -- Freeway -- Frequency -- Fresh water -- Friction -- Frigatebirds -- Frogs -- Frog's-bit family -- Frostbite -- Fruits -- Fuel cells -- Fukushima nuclear accident -- Function -- Fundamental theorems -- Fungi -- Fungicide -- Gaia hypothesis -- Galaxy -- Galileo project -- Game theory -- Gamete -- Gametogenesis -- Gamma-ray astronomy -- Gamma-ray burst -- Gangrene -- Garpike -- Gases, liquefaction of -- Gases, properties of -- Gazelles -- Gears -- Geckos -- Geese -- Gelatin -- Gene -- Gene chips and microarrays -- Gene editing -- Gene mutation -- Gene splicing -- Gene therapy -- Generator -- Genetic disorders -- Genetic engineering -- Genetic identification of microorganisms -- Genetic testing -- Genetically modified organisms -- Genetics -- Genets -- Genome -- Genomics (comparative) -- Genotype and phenotype -- Geocentric theory -- Geochemical analysis -- Geochemistry -- Geode -- Geodesic -- Geodesic dome -- Geoengineering -- Geographic and magnetic poles -- Geologic map -- Geologic time -- Geology -- Geomagnetic storms -- Geometry -- Geomicrobiology -- Geophysics -- Geospatial imagery -- Geothermal energy -- Geotropism -- Gerbils -- Germ cells and the germ cell line -- Germ theory -- Germination -- Gerontology -- Gesnerias -- Geyser -- Gibbons and siamangs -- Gila monster -- Ginger -- Ginkgo -- Ginseng -- Giraffes and okapi -- GIS -- Glaciers -- Glands -- Glass -- Global climate -- Global dimming -- Global Positioning System -- Global warming -- Glycerol -- Glycol -- Glycolysis -- Goats -- Goatsuckers-- Gobies -- Goldenseal -- Gophers -- Gorillas -- Gourd family (Cucurbitaceae) -- Graft -- Grand unified theory -- Grapes -- Graphs and graphing -- Grasses -- Grasshoppers -- Grasslands -- Gravitational lens -- Gravitational waves and astronomy -- Gravity and gravitation -- Great Barrier Reef -- Greatest common factor -- Grebes -- Greenhouse effect -- Groundhog -- Groundwater -- Group -- Grouse -- Growth and decay -- Growth hormones -- Guenons -- Guillain-Barre syndrome -- Guinea pigs and cavies -- Guineafowl -- Gulls -- Guppy -- Gutenberg discontinuity -- Gutta percha -- Gymnosperm -- Gynecology -- Gyroscope -- H1N1 pandemic swine flu -- H5N1 avian influenza -- H7N9 avian influenza -- Habitat -- Hagfish -- Half-life -- Halide, organic -- Hall effect -- Halley's comet -- Hallucinogens -- Halogenated hydrocarbons -- Halogens -- Halosaurs -- Hamsters -- Hand tools -- Hantavirus infections -- Hard water -- Harmonics -- Hartebeests -- Hawks -- Hazardous wastes -- Hazel -- Health geography -- Hearing -- Heart -- Heart disease -- Heart, embryonic development and changes at birth -- Heart, rhythm control and impulse conduction -- Heart-lung machine -- Heat -- Heat capacity -- Heat index -- Heat transfer -- Heath family (Ericaceae) -- Hedgehogs -- Heisenberg uncertainty principle -- Heliocentric theory -- Heliosphere -- Hematology -- Hemoglobin -- Hemophilia -- Hemorrhagic fevers and diseases -- Hemp -- Henna -- Hepatitis -- Hepatitis A virus (HAV) -- Hepatitis B virus (HBV) -- Hepatitis C virus (HCV) -- Hepatitis D virus (HDV) -- Hepatitis E virus (HEV) -- Herb -- Herbal medicine -- Herbicides -- Herbivore -- Herd immunity -- Hermaphrodite --

Hernia -- Herons -- Herpetology -- Herrings -- Hertzsprung-Russell diagram -- Heterotroph -- Hibernation -- Higgs boson -- Himalayas, geology of -- Hippopotamus -- Histamine -- Historical geography -- Historical geology -- Hoatzin -- Hodgkin's disease -- Holly family (Aquifoliaceae) -- Hologram and holography -- Holographic principle -- Homeostasis -- Honeycreepers -- Honeyeaters -- Hoopoe -- Horizon -- Hormones -- Hornbills -- Horse chestnut -- Horsehair worms -- Horses -- Horseshoe crabs -- Horsetails -- Horticulture -- Hot spot -- Hovercraft -- Hubble constant -- Hubble Space Telescope -- Human artificial chromosomes -- Human chorionic gonadotropin -- Human cloning -- Human ecology -- Human evolution -- Human Genome Project -- Human geography -- Human population -- Humidity -- Hummingbirds -- Humus -- Huntington disease -- Hurricane Harvey -- Hurricane Irma -- Hurricane Sandy -- Hybrid -- Hybrid transportation -- Hydra -- Hydrocarbon -- Hydrocephalus -- Hydrochlorofluorocarbons -- Hydroelectric power -- Hydrofoil -- Hydrogen -- Hydrogen chloride -- Hydrogen peroxide -- Hydrogenation -- Hydrology -- Hydrolysis -- Hydroponics -- Hydrosphere -- Hydrothermal vents -- Hydrozoa -- Hyena -- Hyperbarics -- Hyperbola -- Hypertension -- Hypothermia -- Hypoxia -- Hyraxes -- Ibises -- Ice -- Ice age refuges -- Ice ages -- Ice and snow cover -- Ice cores -- Icebergs -- Iceman -- Identity element -- Identity property -- Igneous rocks -- Iguanas -- Illegal drugs -- Imaginary number -- Immune system -- Immunology -- Impact crater -- Imprinting -- In vitro and in vivo -- In vitro fertilization (IVF) -- Incandescent light -- Incineration -- Indicator, acid-base -- Indicator species -- Individual -- Indoor air quality -- Industrial minerals -- Industrial Revolution -- Inequality -- Inertial guidance -- Infection -- Infectious diseases -- Infertility -- Infinity -- Inflammation -- Inflection point -- Influenza -- Infrared astronomy -- Infrared detection devices -- Inherited disorders -- Insecticides -- Insectivore -- Insects -- Insolation -- Insomnia -- Instinct -- Insulin -- Integers -- Integral -- Integrated circuit -- Integrated pest management -- Integumentary system -- Interference -- Interferometry -- Interferons -- Internal combustion engine -- International Space Station -- International Ultraviolet Explorer -- Internet and the World Wide Web -- Internet file transfer and tracking -- Internet search engine -- Interstellar matter -- Interval -- Introduced species -- Invariant -- Invasive species -- Invertebrates -- Ion and ionization -- Ion exchange -- Ionizing radiation -- Iris family -- Iron -- Irrational number -- Irrigation -- Island -- Isoantibodies -- Isobars -- Isomer -- Isostasy -- Isotope -- Isotopic analysis -- Isthmus -- Iteration -- Jacanas -- Jacks -- Jatropha -- Jaundice -- Jellyfish -- Jerboas -- Jet engine -- Jet stream -- Juniper -- Jupiter -- Kangaroo rats -- Kangaroos and wallabies -- Karst topography -- Karyotype and karyotype analysis -- Kelp forests -- Kepler's laws -- Keystone species -- Killifish -- Kingdom -- Kingfishers -- Kinglets -- Koalas -- Koch's postulates -- Kola -- Korsakoff's syndrome -- Krebs cycle -- K-T event (Cretaceous-Tertiary event) -- Kuiper belt objects -- Kuru -- Lacewings -- Lactic acid -- Lagomorphs -- Lake -- Lamarckism -- Lampreys and hagfishes -- Land and sea breezes -- Land use -- Landfill -- Landform -- Langurs and leaf-monkeys -- Lantern fish -- Lanthanides -- Large Hadron Collider -- Larks -- Laryngitis -- Laser -- Laser surgery -- Latitude and longitude -- Laurel family (Lauraceae) -- Laws of motion -- LCD -- Leaching -- Lead -- Leaf -- Leafhoppers -- Learning -- Least common denominator -- Lecithin -- LED -- Legionnaire disease -- Legumes -- Lemmings -- Lemurs -- Lens -- Leprosy -- Leukemia -- Lewis structure -- Lice -- Lichens -- Life history -- Ligand -- Light -- Light pollution -- Lightning -- Light-year -- Lilac -- Lily family (Liliaceae) -- Limit -- Limiting factor -- Limpets -- Line, equations of -- Linear algebra -- Lipid -- Liquid crystals -- Lithium -- Lithography -- Lithosphere -- Lithotripsy -- Liverwort -- Livestock -- Lobsters -- Lock -- Lock and key -- Locus -- Logarithms -- Loons -- Loop quantum gravity -- LORAN -- Lorises -- Luminescence -- Lungfish -- Lycophytes -- Lyme disease -- Lymphatic system -- Lyrebirds -- Macaques -- Mach number -- Machine tools -- Machine vision -- Machines, simple -- Mackerel -- Magic square -- Magma -- Magnesium -- Magnesium sulfate -- Magnetic levitation -- Magnetic recording/audiocassette -- Magnetic resonance imaging (MRI) -- Magnetism -- Magnetosphere -- Magnolia -- Mahogany -- Maidenhair fern -- Malaria -- Malnutrition -- Mammals -- Manakins -- Mangrove tree -- Mania -- Map -- Maples -- Marfan syndrome -- Marijuana -- Marine toxins -- Marlins -- Marmosets and tamarins -- Marmots -- Mars -- Mars exploration rovers -- Mars Pathfinder -- Marsupial cats -- Marsupial rats and mice -- Marsupials -- Marten, sable, and fisher -- Maser -- Mass -- Mass extinction -- Mass number -- Mass production -- Mass spectrometry -- Mass transportation -- Mass wasting -- Materials science -- Mathematics -- Matrix -- Matter -- Maunder minimum -- Maxima and minima -- Mayflies -- Mean -- Mechanical engineering -- Median -- Medical genetics -- Meiosis -- Membrane -- Memory -- Mendelian genetics -- Meningitis -- Menopause -- Menstrual cycle -- Mercurous chloride -- Mercury (element) -- Mercury (planet) -- MERS (Middle East Respiratory syndrome) -- Mesoscopic systems -- Mesozoa -- Metabolic disorders -- Metabolism -- Metal -- Metal detectors -- Metal fatigue -- Metal production -- Metallurgy -- Metamorphic grade -- Metamorphic rock -- Metamorphism -- Metamorphosis -- Meteorology -- Meteors and meteorites -- Methamphetamine -- Methyl group -- Metric system -- Mice -- Michelson-Morley experiment -- Microbial archaeology -- Microbial genetics -- Microbiome -- Microchip -- Microclimate -- Microorganisms -- Microplastics -- Microscope -- Microscopy -- Microtechnology -- Microwave communication -- Migraine headache -- Migration -- Mildew -- Milkweeds -- Milky Way -- Miller-Urey experiment -- Millipedes -- Mimicry -- Mineralogy -- Minerals -- Mining -- Mink -- Minnows -- Minor planets -- Mint family -- Mir Space Station -- Mirrors -- Miscibility -- Mistletoe -- Mites -- Mitochondrial DNA analysis -- Mitosis -- Mixture, chemical -- Mobius strip -- Mockingbirds and thrashers -- Mode -- Model organisms -- Modular arithmetic -- Mohs' scale -- Mold -- Mole -- Molecular biology -- Molecular formula -- Molecular geometry -- Molecular weight -- Molecule -- Mole-rats -- Moles -- Mollusks -- Momentum -- Monarch flycatchers -- Mongooses -- Monitor lizards -- Monkeys -- Monochromatic light -- Monoculture -- Monomer -- Monosodium glutamate (MSG) -- Monotremes -- Monsoon -- Montreal Biodome -- MOOC (Massive open online course) --

Moon -- Mooneyes -- Moose -- Morphine -- Mosquitoes -- Moss -- Moss animals -- Mossbauer effect -- Moths -- Motion -- Motion pictures -- Moundbuilders -- Mounds, earthen -- Mountains -- Mousebirds -- Mulberry family (Moraceae) -- Multiple personality disorder -- Multiplication -- Murchison meteorite -- Muscle relaxants -- Muscular system -- Mushrooms -- Muskoxen -- Muskrat -- Mustard family (Brassicaceae) -- Mustard gas -- Mutagen -- Mutagenesis -- Mutation -- Mutualism -- Mycorrhiza -- Mycotoxin -- Mynah birds -- Myrtle family (Myrtaceae) -- Nanotechnology -- Narcotic -- Natural fibers -- Natural gas -- Natural numbers -- Nautical archaeology -- N-body problem -- Near-Earth Object Hazard Index -- Nectar -- Negative -- Neptune -- Nerve gas -- Nerve growth factor -- Nerve impulses and conduction of impulses -- Nervous system -- Neuromuscular diseases -- Neuron -- Neuroscience -- Neurosurgery -- Neurotransmitter -- Neutralization -- Neutrino -- Neutron -- Neutron activation analysis -- Neutron star -- New World monkeys -- Newton's laws of motion -- Newts -- Niche -- Nicotine -- Night vision enhancement devices -- Nightshade -- Nitric acid -- Nitrification -- Nitrogen -- Nitrogen cycle -- Nitrogen fixation -- Nobel Prize -- Noise pollution -- Non-Euclidean geometry -- Nonmetal -- Nonpoint source -- North America -- Nova -- Novocain -- Nuclear engineering -- Nuclear fission -- Nuclear fusion -- Nuclear magnetic resonance -- Nuclear medicine -- Nuclear power -- Nuclear reactor -- Nuclear weapons -- Nuclear winter -- Nucleic acid -- Nucleon -- Nucleus, cellular -- Numbat -- Number theory -- Numeration systems -- Nut -- Nuthatches -- Nutmeg -- Nutrient deficiency diseases -- Nutrients -- Nutrition -- Nux vomica tree -- Oaks -- Obesity -- Obsession -- Ocean acidification -- Ocean basin -- Ocean currents -- Ocean sunfish -- Ocean zones -- Oceanography -- Oceans -- Ockham's razor -- Octet rule -- Octopus -- Odds -- Odontology -- Ohm's law -- Oil and gas pipelines -- Oil spills -- Oil well drilling -- Old-growth forests -- Olive family (Oleaceae) -- Omnivore -- One-to-one correspondence -- Opah -- Open-source software -- Opossums -- Opportunistic species -- Optical data storage -- Optics -- Orangutans -- Orbit -- Orchid family (Orchidaeceae) -- Ordinal number -- Ore -- Organ -- Organelles and subcellular genetics -- Organic farming -- Organism -- Organogenesis -- Organs and organ systems -- Origin of life -- Origins of the universe -- Orioles -- Ornithology -- Orthopedics -- Oryx -- Oscillating reactions -- Oscillations -- Oscilloscope -- Osmosis -- Osmosis (cellular) -- Ossification -- Osteoporosis -- Otter shrews -- Otters -- Outcrop -- Ovarian cycle and hormonal regulation -- Ovenbirds -- Oviparous -- Ovoviviparous -- Owls -- Oxalic acid -- Oxidation state -- Oxidation-reduction reaction -- Oxygen -- Oystercatchers -- Ozone -- Ozone layer depletion -- Pacemaker -- Pain -- Paleobotany -- Paleoclimate -- Paleoecology -- Paleomagnetism -- Paleontology -- Paleopathology -- Palindrome -- Palms -- Palynology -- Pandas -- Pangolins -- Papaya -- Paper -- Parabola -- Parallax -- Parallel -- Parallelogram -- Parasites -- Parasitology -- Parity -- Parkinson disease -- Parrots -- Parthenogenesis -- Particle detectors -- Partridges -- Pascal's triangle -- Passion flower -- Paternity and parentage testing -- Pathogens -- Pathology -- PCR -- Peafowl -- Peanut worms -- Peccaries -- Pedigree analysis -- Pelicans -- Penguins -- Peninsula -- Pentyl group -- Peony -- Pepper -- Peptide linkage -- Percent -- Perception -- Perch -- Peregrine falcon -- Perfect numbers -- Performance-enhancing drugs -- Periodic functions -- Periodic table -- Permafrost -- Perpendicular -- Personal digital assistant -- Personal music players -- Pesticides -- Pests -- Petrels and shearwaters -- Petroglyphs and pictographs -- Petroleum -- pH -- Phalangers -- Pharmacogenetics -- Pharmacogenomics -- Pheasants -- Phenyl group -- Phenylketonuria -- Pheromones -- Phlox -- Phobias -- Phonograph -- Phoronids -- Phosphoric acid -- Phosphorus -- Phosphorus cycle -- Phosphorus removal -- Photic zone -- Photochemistry -- Photocopying -- Photoelectric cell -- Photoelectric effect -- Photogrammetry -- Photographic resolution -- Photography -- Photography, electronic -- Photon -- Photosynthesis -- Phototropism -- Photovoltaic cell -- Phylogeny -- Physical therapy -- Physics -- Physiology -- Physiology, comparative -- Phytoplankton -- Pi -- Pigeons and doves -- Pigs -- Pike -- Piltdown hoax -- Pinecone fish -- Pines -- Pipefish -- Placebo -- Planck's constant -- Plane -- Plane family -- Planet -- Planet X -- Planetary atmospheres -- Planetary geology -- Planetary nebulae -- Planetary ring systems -- Plankton -- Plant -- Plant breeding -- Plant diseases -- Plant pigment -- Plasma -- Plastic surgery -- Plastics -- Plate tectonics -- Platonic solids -- Platypus -- Plovers -- Pluto -- Pneumonia -- Podcast -- Podiatry -- Point -- Point source -- Poisons and toxins -- Polar coordinates -- Polar ice caps -- Poliomyelitis -- Pollen analysis -- Pollination -- Pollution -- Pollution control -- Polybrominated biphenyls (PBBs) -- Polychlorinated biphenyls (PCBs) -- Polycyclic aromatic hydrocarbons -- Polygons -- Polyhedron -- Polymer -- Polynomials -- Poppies -- Population geography -- Population growth and control (human) -- Porcupines -- Positive number -- Positron emission tomography (PET) -- Postulate -- Potassium aluminum sulfate -- Potassium hydrogen tartrate -- Potassium iodide -- Potassium nitrate -- Potato -- Pottery analysis -- Prairie -- Prairie chicken -- Prairie dog -- Prairie falcon -- Praying mantis -- Precession of the equinoxes -- Precious metals -- Precipitation -- Predator -- Prenatal surgery -- Prescribed burn -- Pressure -- Prey -- Primates -- Prime numbers -- Primroses -- Printing -- Prions -- Prism -- Probability -- Probability theory -- Proboscis monkey -- Projective geometry -- Prokaryote -- Pronghorn -- Proof -- Propyl group -- Prosimians -- Prosthetics -- Proteas -- Protected area -- Proteins -- Proteomics -- Protista -- Proton -- Protozoa -- Psychiatry -- Psychoanalysis -- Psychology -- Psychometry -- Psychosis -- Psychosurgery -- Puberty -- Puffbirds -- Puffer fish -- Pulsar -- Punctuated equilibrium -- Pyramid -- Pythagorean theorem -- Pythons -- Quadrilateral -- Quail Qualitative analysis -- Quantitative analysis -- Quantum computing -- Quantum electrodynamics (QED) -- Quantum entanglement -- Quantum mechanics -- Quantum number -- Quarks -- Quasar -- Quasicrystals -- Quetzal -- Quinine -- Rabies -- Raccoons -- Radar -- Radial keratotomy -- Radiation -- Radiation detectors -- Radiation exposure -- Radical (atomic) -- Radical (math) -- Radio -- Radio astronomy -- Radio waves -- Radioactive dating -- Radioactive decay -- Radioactive fallout -- Radioactive pollution -- Radioactive tracers -- Radioactive waste -- Radioisotopes in medicine -- Radiology -- Radon --

Rails -- Rainbows -- Rainforest -- Random -- Rangeland -- Raptors -- Rare gases -- Rare genotype advantage -- Rate -- Ratio -- Rational number -- Rationalization -- Rats -- Rayleigh scattering -- Rays -- Real numbers -- Reciprocal -- Recombinant DNA -- Rectangle -- Recycling -- Red giant star -- Red tide -- Redshift -- Reflections -- Reflex -- Refrigerated trucks and railway cars -- Rehabilitation -- Reinforcement, positive and negative -- Relation -- Relativity, general -- Relativity, special -- Remote sensing -- Reproductive system -- Reproductive toxicant -- Reptiles -- Resins -- Resonance -- Resources, natural -- Respiration -- Respirator -- Respiratory diseases -- Respiratory system -- Restoration ecology -- Retrograde motion -- Retrovirus -- Reye's syndrome -- Rh factor -- Rhesus monkeys -- Rheumatic fever -- Rhinoceros -- Rhizome -- Rhubarb -- Ribbon worms -- Ribonuclease -- Ribonucleic acid (RNA) -- Ribosomes -- Rice -- Ricin -- Rickettsia -- Rigor mortis -- Rinderpest -- Rivers -- RNA function -- RNA splicing -- Robins -- Robotic vehicles -- Robotics -- Rockets and missiles -- Rocks -- Rodents -- Rollers -- Root system -- Rose family (Rosaceae) -- Rotation -- Roundworms -- Rumination -- Rushes -- Rusts and smuts -- Saiga antelope -- Salamanders -- Saliva -- Salmon -- Salmonella -- Salt -- Salt marshes -- Saltwater -- Sample -- Sand -- Sand dollars -- Sandfish -- Sandpipers -- Sanitation -- Sapodilla tree -- Sardines -- Sarin gas -- SARS (severe acute respiratory syndrome) -- Satellite -- Saturn -- Savanna -- Savant -- Sawfish -- Saxifrage family -- Scalar -- Scale insects -- Scanners, digital -- Scanning electron microscopy -- Scarlet fever -- Scavenger -- Schizophrenia -- Science History -- Scientific debate -- Scientific method -- Scientific theories and laws -- Scorpion flies -- Scorpionfish -- Screamers -- Screwpines -- Sculpins -- Sea anemones -- Sea cucumbers -- Sea level -- Sea lily -- Sea lions -- Sea moths -- Sea spiders -- Sea squirts and salps -- Sea urchins -- Seahorses -- Seals -- Seamounts -- Seasonal winds -- Seasons -- Secondary pollutants -- Secretary bird -- Secretor -- Sedges -- Sediment and sedimentation -- Sedimentary environment -- Sedimentary rock -- Seed ferns -- Seeds -- Segmented worms -- Seismograph -- Selection -- Sequences -- Sequencing -- Sequoia -- Serology -- Servomechanisms -- Sesame -- Set theory -- SETI -- Sewage treatment -- Sewing machine -- Sex change -- Sex determination -- Sextant -- Sexual dimorphism -- Sexual reproduction -- Sexually transmitted diseases -- Sharks -- Sheep -- Shell midden analysis -- Shingles -- Shore birds -- Shoreline protection -- Shotgun cloning -- Shrews -- Shrikes -- Shrimp -- Sickle cell anemia -- Sieve of Eratosthenes -- Silicon -- Silk cotton family (Bombacaceae) -- Sinkholes -- Skates -- Skeletal analysis -- Skeletal system -- Skinks -- Skuas -- Skunks -- Slash-and-burn agriculture -- Sleep -- Sleep disorders -- Sleeping sickness -- Slime molds -- Sloths -- Slugs -- Smallpox -- Smallpox vaccine -- Smell -- Smog -- Snails -- Snakeflies -- Snakes -- Snapdragon family -- Soap -- Sociobiology -- Sodium -- Sodium benzoate -- Sodium bicarbonate -- Sodium carbonate -- Sodium chloride -- Sodium hydroxide -- Sodium hypochlorite -- Soil -- Soil conservation -- Solar activity cycle -- Solar flare -- Solar geoengineering -- Solar illumination: Seasonal and diurnal patterns -- Solar prominence -- Solar system -- Solar wind -- Solder and soldering iron -- Solstice -- Solubility -- Solution -- Solution of equation -- SONAR -- Song birds -- Sonoluminescence -- Sorghum -- Sound waves -- South America -- Soybean -- Space -- Space probe -- Space shuttle -- Spacecraft, crewed -- Sparrows and buntings -- Species -- Spectral classification of stars -- Spectral lines -- Spectroscope -- Spectroscopy -- Spectrum -- Speech -- Sphere -- Spider monkeys -- Spiderwort family -- Spin of subatomic particles -- Spina bifida -- Spinach -- Spiny anteaters -- Spiny eels -- Spiny-headed worms -- Spiral -- Spirometer -- Split-brain functioning -- Sponges -- Spontaneous generation -- Spore -- Springtails -- Spruce -- Spurge family -- Square -- Square root -- Squid -- Squirrel fish -- Squirrels -- Stalactites and stalagmites -- Standard Model -- Star -- Star cluster -- Star formation -- Starburst galaxy -- Starfish -- Starlings -- States of matter -- Statistical mechanics -- Statistics -- Steady-state theory -- Stealth technology -- Steam engine -- Steam pressure sterilizer -- Stearic acid -- Steel -- Steganography -- Stellar evolution -- Stellar magnetic fields -- Stellar magnitudes -- Stellar populations -- Stellar structure -- Stellar wind -- Stem cells -- Stereochemistry -- Sticklebacks -- Stilts and avocets -- Stimulus -- Stoichiometry -- Stone and masonry -- Stoneflies -- Storks -- Storm -- Storm surge -- Strata -- Stratigraphy -- Stratigraphy (archaeology) -- Stream capacity and competence -- Stream valleys, channels, and floodplains -- Strepsiptera -- Stress -- Stress, ecological -- String theory -- Stroke -- Stromatolite -- Structural analysis -- Sturgeons -- Subatomic particles -- Sublimation -- Submarine -- Subsidence -- Subsurface detection -- Subtraction -- Succession -- Suckers -- Sudden infant death syndrome (SIDS) -- Sugar beet -- Sugarcane -- Sulfur -- Sulfur cycle -- Sulfur dioxide -- Sulfuric acid -- Sun -- Sunbirds -- Sunspots -- Super heavy elements -- Superclusters -- Superconductor -- Supernova -- Surface tension -- Surgery -- Surveying instruments -- Survival of the fittest -- Sustainability -- Sustainable development -- Swallows and martins -- Swamp cypress family (Taxodiaceae) -- Swamp eels -- Swans -- Sweet gale family (Myricaceae) -- Sweet potato -- Swifts -- Swordfish -- Symbiosis -- Symbol, chemical -- Symbolic logic -- Symmetry -- Synapse -- Syndrome -- Synthesis, chemical -- Synthesizer, music -- Synthesizer, voice -- Systematics -- Systems of equations -- T cells -- Tabun -- Tanagers -- Taphonomy -- Tapirs -- Tarpons -- Tarsiers -- Tartaric acid -- Tasmanian devil -- Taste -- Taxonomy -- Tay-Sachs disease -- Tea plant -- Telegraph -- Telemetry -- Telephone -- Telescope -- Television -- Temperature -- Temperature regulation -- Tenrecs -- Teratogen -- Term -- Termites -- Terns -- Terracing -- Territoriality -- Tetanus -- Tetrahedron -- Textiles -- Thalidomide -- Thanatology -- Theorem -- Thermal expansion -- Thermochemistry -- Thermocouple -- Thermodynamics -- Thermoluminescence -- Thermometer -- Thermostat -- Thistle -- Thoracic surgery -- 3D imaging -- 3D printing -- Thrips -- Thrombosis -- Thrushes -- Thunderstorm -- Tides -- Time -- Tinamous -- Tissue -- Tit family -- Titanium -- Toadfish -- Toads -- Tomato family (Solanaceae) -- Tongue worms -- Tonsillitis -- Topology -- Tornado -- Torque -- Torus -- Total solar irradiance -- Toucans --

Touch

Towers of Hanoi

Toxic shock syndrome

Toxicology

Trace elements

Tragopans

Trains and railroads

Tranquilizers

Transcendental numbers

Transducer

Transformer

Transgenics

Transistor

Transitive

Translations

Transpiration

Transplant, surgical

Trapezoid

Tree

Tree shrews

Trichinosis

Triggerfish

Triglycerides

Trigonometry

Tritium

Trogons

Trophic levels

Tropic birds

Tropical cyclone

Tropical diseases

Trout-perch

True bugs

True eels

True flies

Trumpetfish

Tsunami

Tuatara lizard

Tuber

Tuberculosis

Tularemia

Tumbleweed

Tumor

Tuna

Tundra

Tunneling

Turacos

Turbine

Turbulence

Turkeys

Turner syndrome

Turtles

Typhoid fever

Typhus

Tyrannosaurus rex

Tyrant flycatchers

Ulcers

Ultracentrifuge

Ultrasonics

Ultraviolet astronomy

Unconformity

Underwater exploration

Ungulates

Uniformitarianism

Units and standards

Uplift

Upwelling

Uranium

Uranus

Urea

Urology

Vaccine

Vaccine hesitancy

Vacuum

Vacuum tube

Valence

Van Allen belts

Van der Waals forces

Vaping and e-cigarettes

Vapor pressure

Variable

Variable stars

Variance

Varicella zoster virus

Variola virus

Vegetables

Veins

Velocity

Venus

Verbena family (Verbenaceae)

Vertebrates

Video recording

Viking project

Violet family (Violaceae)

Vipers

Viral genetics

Vireos

Virtual particles

Virtual reality

Virus

Viscosity

Vision

Vision correction surgery

Vision disorders

Vitamin

Viviparity

Vivisection

Volatility

Volcano

Voles

Volume

Voyager spacecraft

Vulcanization

Vultures

VX agent

Wagtails and pipits

Walkingsticks

Walnut family

Walruses

Warblers

Wasps

Waste management

Waste, toxic

Water

Water bears

Water conservation

Water cycle (hydrologic cycle)

Water lilies

Water microbiology

Water pollution

Water treatment

Waterbuck

Watershed

Waterwheel

Wave motion

Waxbills

Waxwings

Weapon-grade plutonium and uranium, tracking

Weasels

Weather

Weather forecasting

Weather mapping

Weather modification

Weathering

Weavers

Weevils

Welding

West

Nile virus

Wetlands

Wheat

Whisk fern

White dwarf

White-eyes

Whooping cough

Wild type

Wildfire

Wildlife

Wildlife trade (illegal)

Willow family (Salicaceae)

Wind

Wind chill

Wind energy

Wind shear

Wintergreen

Wireless communications

Wolverine

Wombats

Wood

Woodpeckers

Woolly mammoth

Work

Wrens

Wren-warblers

Wrynecks

Xenogamy

Xenotransplantation

X-ray astronomy

X-ray crystallography

X-rays

Xylotomy

Yak

Yam

Yeast

Yellow fever

Yew

Yttrium

Y2K

Zebras

Zero

Zika virus

Zodiacal light

Zoonoses

Zooplankton.