Matter & Energy, GLU-HYD
Matter is the material substance that constitutes the observable universe and, together with energy, forms the basis of all objective phenomena. Energy, in physics, is the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms.
Matter & Energy Encyclopedia Articles By Title
gluon
gluon, the so-called messenger particle of the strong nuclear force, which binds subatomic particles known as quarks......
Glutamic acid
Glutamic acid, an amino acid occurring in substantial amounts as a product of the hydrolysis of proteins. Certain......
Glutamine
Glutamine, an amino acid, the monoamide of glutamic acid, and an abundant constituent of proteins. First isolated......
Glutathione
Glutathione, a tripeptide (i.e., compound composed of three amino acids), the chemical name of which is Îł-l-glutamyl-l-cysteinylglycine.......
Gluten
Gluten, a yellowish gray powdery mixture of water-insoluble proteins occurring in wheat and other cereal grains......
glycerol
glycerol, a clear, colourless, viscous, sweet-tasting liquid belonging to the alcohol family of organic compounds;......
Glycine
Glycine, the simplest amino acid, obtainable by hydrolysis of proteins. Sweet-tasting, it was among the earliest......
Glycogen
Glycogen, white, amorphous, tasteless polysaccharide (C6H1005)n. It is the principal form in which carbohydrate......
glycol
glycol, any of a class of organic compounds belonging to the alcohol family; in the molecule of a glycol, two hydroxyl......
Glycolipid
Glycolipid, any of a group of molecules consisting of a carbohydrate (sugar) moiety attached to a lipid (fat) backbone.......
glycolysis
glycolysis, sequence of 10 chemical reactions taking place in most cells that breaks down glucose, releasing energy......
Glycoside
Glycoside, any of a wide variety of naturally occurring substances in which a carbohydrate portion, consisting......
Goitrogen
Goitrogen, substance that inhibits the synthesis of the thyroid hormones (thyroxine and triiodothyronine), thereby......
gold
gold (Au), chemical element, a dense lustrous yellow precious metal of Group 11 (Ib), Period 6, of the periodic......
gonadotropin
gonadotropin, any of several hormones occurring in vertebrates that are secreted from the anterior pituitary gland......
gonadotropin-releasing hormone
gonadotropin-releasing hormone (GnRH), a neurohormone consisting of 10 amino acids that is produced in the arcuate......
grain
grain, in metallurgy, any of the crystallites (small crystals or grains) of varying, randomly distributed, small......
graphene
graphene, a two-dimensional form of crystalline carbon, either a single layer of carbon atoms forming a honeycomb......
graphite
graphite, mineral consisting of carbon. Graphite has a greasy feel and leaves a black mark, thus the name from......
gravimetric analysis
gravimetric analysis, a method of quantitative chemical analysis in which the constituent sought is converted into......
Gravitational wave
Gravitational wave, the transmission of variations in the gravitational field as waves. According to general relativity,......
graviton
graviton, postulated quantum particle that is thought to be the carrier of the gravitational field. It is analogous......
gravity
gravity, in mechanics, the universal force of attraction acting between all bodies of matter. It is by far the......
gravity, centre of
centre of gravity, in physics, an imaginary point in a body of matter where, for convenience in certain calculations,......
Gravity: From Apples to the Universe
Why do objects fall to the ground? âBecause of gravity,â you say. But what is gravity? The ancient Greek philosopher......
Green
Green, in physics, light in the wavelength range of 495â570 nanometres, which is in the middle of the visible spectrum.......
Greenwich Mean Time
Greenwich Mean Time (GMT), the name for mean solar time of the longitude (0°) of the Royal Greenwich Observatory......
Grignard reagent
Grignard reagent, any of numerous organic derivatives of magnesium (Mg) commonly represented by the general formula......
group
group, in chemistry, a column in the periodic table of the chemical elements. In a group, the chemical elements......
growth factor
growth factor, any of a group of proteins that stimulate the growth of specific tissues. Growth factors play an......
Growth hormone
Growth hormone (GH), peptide hormone secreted by the anterior lobe of the pituitary gland. It stimulates the growth......
growth hormone-releasing hormone
growth hormone-releasing hormone (GHRH), a large peptide hormone that exists in several forms that differ from......
Guanine
Guanine, an organic compound belonging to the purine group, a class of compounds with a characteristic two-ringed......
Gunn effect
Gunn effect, high-frequency oscillation of electrical current flowing through certain semiconducting solids. The......
hadron
hadron, any member of a class of subatomic particles that are built from quarks and thus react through the agency......
hafnium
hafnium (Hf), chemical element (atomic number 72), metal of Group 4 (IVb) of the periodic table. It is a ductile......
half-life
half-life, in radioactivity, the interval of time required for one-half of the atomic nuclei of a radioactive sample......
Hall effect
Hall effect, development of a transverse electric field in a solid material when it carries an electric current......
Halo
Halo, any of a wide range of atmospheric optical phenomena that result when the Sun or Moon shines through thin......
halocarbon
halocarbon, any chemical compound of the element carbon and one or more of the halogens (bromine, chlorine, fluorine,......
halogen
halogen, any of the six nonmetallic elements that constitute Group 17 (Group VIIa) of the periodic table. The halogen......
halon
halon, chemical compound formerly used in firefighting. A halon may be any of a group of organohalogen compounds......
haptoglobin
haptoglobin, a colourless protein of the α-globulin fraction of human serum (liquid portion of blood plasma after......
hard water
hard water, water that contains salts of calcium and magnesium principally as bicarbonates, chlorides, and sulfates.......
Harmine
Harmine, hallucinogenic alkaloid found in the seed coats of a plant (Peganum harmala) of the Mediterranean region......
Has Pink Always Been a âGirlyâ Color?
If you see newborn babies at a hospital in the U.S., youâll most likely see them in pink or blue outfits to mark......
hassium
hassium (Hs), an artificially produced element belonging to the transuranium group, atomic number 108. It was synthesized......
Hawking radiation
Hawking radiation, Radiation theoretically emitted from just outside the event horizon of a black hole. Stephen......
heat
heat, energy that is transferred from one body to another as the result of a difference in temperature. If two......
heat capacity
heat capacity, ratio of heat absorbed by a material to the temperature change. It is usually expressed as calories......
heat of formation
heat of formation, the amount of heat absorbed or evolved when one mole of a compound is formed from its constituent......
heat transfer
heat transfer, any or all of several kinds of phenomena, considered as mechanisms, that convey energy and entropy......
heavy water
heavy water (D2O), water composed of two atoms of deuterium, the hydrogen isotope with a mass double that of ordinary......
helium
helium (He), chemical element, inert gas of Group 18 (noble gases) of the periodic table. The second lightest element......
hemagglutinin
hemagglutinin, any of a group of naturally occurring glycoproteins that cause red blood cells (erythrocytes) to......
Hemicellulose
Hemicellulose, any of a group of complex carbohydrates that, with other carbohydrates (e.g., pectins), surround......
Hemochromogen
Hemochromogen, compound of the iron-containing pigment heme with a protein or other substance. The hemochromogens......
hemoglobin
hemoglobin, iron-containing protein in the blood of many animalsâin the red blood cells (erythrocytes) of vertebratesâthat......
henry
henry, unit of either self-inductance or mutual inductance, abbreviated H, and named for the American physicist......
Henryâs law
Henryâs law, statement that the amount (C) of a gas dissolved by a liquid is proportional to the pressure (P) of......
heparin
heparin, anticoagulant drug that is used to prevent blood clots from forming during and after surgery and to treat......
heptachlor
heptachlor, largely banned insecticide closely related to chlordane. It is a white crystalline solid with a melting......
heterocyclic compound
heterocyclic compound, any of a major class of organic chemical compounds characterized by the fact that some or......
- Introduction
- Aromatic, Cyclic, Acyclic
- Aromaticity, Structure, Reactivity
- Melting, Boiling, Points
- Nucleophilic, Ring Closure
- Aromatic, Aliphatic, Heteroatoms
- Five-Membered Rings, Heteroatom
- Six-Membered Rings, Heteroatom, Aromaticity
- Five-Membered, Six-Membered, Heteroatoms
- Uncommon Heteroatoms, Aromaticity, Reactivity
hexachloroplatinic acid
hexachloroplatinic acid (H2PtCl6â6H2O), complex compound formed by dissolving platinum metal in aqua regia (a mixture......
hexagonal system
hexagonal system, one of the principal categories of structures to which a given crystalline solid can be assigned.......
Higgs boson
Higgs boson, particle that is the carrier particle, or boson, of the Higgs field, a field that permeates space......
high-density polyethylene
high-density polyethylene (HDPE), linear version of polyethylene, a light versatile synthetic resin made from the......
high-pressure phenomena
high-pressure phenomena, changes in physical, chemical, and structural characteristics that matter undergoes when......
Histidine
Histidine, an amino acid obtainable by hydrolysis of many proteins. A particularly rich source, hemoglobin (the......
Histone
Histone, type of protein that plays a critical role in the structural organization and regulation of DNA within......
hole
hole, in condensed-matter physics, the name given to a missing electron in certain solids, especially semiconductors.......
Holliday junction
Holliday junction, cross-shaped structure that forms during the process of genetic recombination, when two double-stranded......
holmium
holmium (Ho), chemical element, a rare-earth metal of the lanthanide series of the periodic table. Holmium is a......
homologous series
homologous series, any of numerous groups of chemical compounds in each of which the difference between successive......
Hookeâs law
Hookeâs law, law of elasticity discovered by the English scientist Robert Hooke in 1660, which states that, for......
Hormone
Hormone, organic substance secreted by plants and animals that functions in the regulation of physiological activities......
- Introduction
- Vertebrates, Endocrine, Neuroendocrine
- LH, ICSH, Endocrine
- Thyroid Gland, Metabolism, Hormone Production
- Parathyroid, Calcium, Parathormone
- Glucagon, Pancreas, Regulation
- Reproductive, Endocrine, Glands
- Endocrine Glands, Secretions, Hormone Functions
- Molting, Insects, Juveniles
- Plant Growth, Photosynthesis, Reproduction
- Growth Inhibitors
How Albert Einstein Developed the Theory of General Relativity
In 1907, two years after the publication of his theory of special relativity, Albert Einstein came to a key realization:......
How are crystals made?
The crystallization process begins with nucleation, the initial step where a small number of particles (that is,......
How are diamonds made?
In nature, diamonds are created within Earthâs mantle at depths exceeding 120 kilometers (75 miles) where temperatures......
How do clouds form?
Cloud formation, a key part of the water cycle, begins as moist air ascends into the atmosphere. This occurs because,......
How do fireflies light up?
Fireflies light up summer nights using a chemical process known as bioluminescence, the key chemical players of......
How do magnets work?
The fundamental principle behind magnetism is the magnetic field, which arises from the motion of electric charges.......
How do mirrors work?
The law of reflection is fundamental to how mirrors work. When light hits a mirror, it reflects off the surface......
How Do Scientists Predict Tsunamis After Earthquakes?
Earthquakes, landslides, volcanic eruptions, and even meteoroid and comet strikes can produce tsunamisâtrains of......
How does dry cleaning work?
Dry cleaning works by using chemical solvents to clean textiles instead of water. In essence, dry cleaning still......
How does electricity work?
Electricity works through the movement of negative charges carried by electrons (negatively charged subatomic particles).......
How does metal rust?
Rust is the result of a chemical reaction between metal, typically iron, and oxygen in the presence of moisture.......
How does sound travel?
Sound travels in waves that are essentially disturbances that move through a medium by causing particles to vibrate......
How is gold formed?
Gold is formed through cosmic and geological processes that involve the concentration and deposition of the metal......
How Is Light Both a Particle and a Wave?
The behavior of light cannot be explained solely by models of particles or solely by models of waves. If light......
How Much Water Should a Person Drink in a Day?
The popular recommendation to drink 8 cups of water every day isnât as definitive as it may seem. The amount of......
How Radioactive Isotopes are Used in Medicine
Radioactive isotopes, or radioisotopes, are species of chemical elements that are produced through the natural......
How Rare Are Rare-Earth Elements?
Not as rare as plutonium, but rarer than carbon. Come on. Donât be cute. Youâre EncyclopĂŠdia Britannica. You have......
How was gravity discovered?
Isaac Newton didnât just see an apple fall from a tree. He saw a clue to how gravity works. In 1687, he proposed......
How will the Roman Space Telescope learn about dark energy and dark matter?
The Nancy Grace Roman Space Telescope is designed to help astronomers answer questions about dark energy and dark......
humic acid
humic acid, one of two classes of natural acidic organic polymer that can be extracted from humus found in soil,......
Huygensâ principle
Huygensâ principle, a statement that all points of a wave front of sound in a transmitting medium or of light in......
Hyaluronic acid
Hyaluronic acid, naturally occurring polysaccharide found in the extracellular matrix of vertebrate tissues, particularly......
Hyaluronidase
Hyaluronidase, any of a group of enzymes that catalyze the hydrolysis (chemical decomposition involving the elements......
hydrate
hydrate, any compound containing water in the form of H2O molecules, usually, but not always, with a definite content......