Avogadro's law
Avogadro's hypothesis | the principle that equal volumes of all gases (given the same temperature and pressure) contain equal numbers of molecules |
big-bang theory
big bang theory | (cosmology) the theory that the universe originated sometime betweenbillion andbillion years ago from the cataclysmic explosion of a small volume of matter at extremely high density and temperature |
| nebular hypothesis | (cosmology) the theory that the solar system evolved from a hot gaseous nebula |
| planetesimal hypothesis | (cosmology) the theory that the solar system was formed by the gravitational accumulation of planetesimals |
steady state theory
continuous creation theory | (cosmology) the theory that the universe maintains a constant average density with matter created to fill the void left by galaxies that are receding from each other, the steady state theory has been abandoned in favor of the big bang theory |
hypothesis
possibility
theory | a tentative insight into the natural world, a concept that is not yet verified but that if true would explain certain facts or phenomena, a scientific hypothesis that survives experimental testing becomes a scientific theory, he proposed a fresh theory of alkalis that later was accepted in chemical practices |
| M-theory | (particle physics) a theory that involves an eleven-dimensional universe in which the weak and strong forces and gravity are unified and to which all the string theories belong |
| string theory | (particle physics) a theory that postulates that subatomic particles are one-dimensional strings |
| theory | a belief that can guide behavior, the architect has a theory that more is less, they killed him on the theory that dead men tell no tales |
| theory | a well-substantiated explanation of some aspect of the natural world, an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena, theories can incorporate facts and laws and tested hypotheses, true in fact and theory |
theory of gravitation
theory of gravity
gravitational theory
Newton's theory of gravitation | (physics) the theory that any two particles of matter attract one another with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them |
preformation
theory of preformation | a theory (popular in the th century and now discredited) that an individual develops by simple enlargement of a tiny fully formed organism (a homunculus) that exists in the germ cell |
| scientific theory | a theory that explains scientific observations, scientific theories must be falsifiable |
| field theory | (physics) a theory that explains a physical phenomenon in terms of a field and the manner in which it interacts with matter or with other fields |
| economic theory | (economics) a theory of commercial activities (such as the production and consumption of goods) |
Malthusianism
Malthusian theory | Malthus' theory that population increase would outpace increases in the means of subsistence |
communications
communication theory | the discipline that studies the principles of transmiting information and the methods by which it is delivered (as print or radio or television etc.), communications is his major field of study |
| set theory | the branch of pure mathematics that deals with the nature and relations of sets |
| group theory | the branch of mathematics dealing with groups |
| Galois theory | group theory applied to the solution of algebraic equations |
probability theory
theory of probability | the branch of applied mathematics that deals with probabilities |
atomism
atomic theory
atomist theory
atomistic theory | (chemistry) any theory in which all matter is composed of tiny discrete finite indivisible indestructible particles, the ancient Greek philosophers Democritus and Epicurus held atomic theories of the universe |
holism
holistic theory | the theory that the parts of any whole cannot exist and cannot be understood except in their relation to the whole, holism holds that the whole is greater than the sum of its parts, holistic theory has been applied to ecology and language and mental states |
| atomic theory | a theory of the structure of the atom |
| Bohr theory | (physics) a theory of atomic structure that combined Rutherford's model with the quantum theory, electrons orbiting a nucleus can only be in certain stationary energy states and light is emitted when electrons jump from one energy state to another |
cell theory
cell doctrine | (biology) the theory that cells form the fundamental structural and functional units of all living organisms, proposed in by Matthias Schleiden and by Theodor Schwann |
wave theory
undulatory theory
wave theory of light | (physics) the theory that light is transmitted as waves |
corpuscular theory
corpuscular theory of light | (physics) the theory that light is transmitted as a stream of particles |
kinetic theory
kinetic theory of gases | (physics) a theory that gases consist of small particles in random motion |
relativity
theory of relativity
relativity theory
Einstein's theory of relativity | (physics) the theory that space and time are relative concepts rather than absolute concepts |
general relativity
general theory of relativity
general relativity theory
Einstein's general theory of relativity | a generalization of special relativity to include gravity (based on the principle of equivalence) |
special relativity
special theory of relativity
special relativity theory
Einstein's special theory of relativity | a physical theory of relativity based on the assumption that the speed of light in a vacuum is a constant and the assumption that the laws of physics are invariant in all inertial systems |
| quantum theory | (physics) a physical theory that certain properties occur only in discrete amounts (quanta) |
| kinetic theory of heat | a theory that the temperature of a body increases when kinetic energy increases |
| germ theory | (medicine) the theory that all contagious diseases are caused by microorganisms |
| information theory | (computer science) a statistical theory dealing with the limits and efficiency of information processing |
theory of dissociation
theory of electrolytic dissociation
Arrhenius theory of dissociation | (chemistry) theory that describes aqueous solutions in terms of acids (which dissociate to give hydrogen ions) and bases (which dissociate to give hydroxyl ions), the product of an acid and a base is a salt and water |
theory of evolution
theory of organic evolution
evolutionism | (biology) a scientific theory of the origin of species of plants and animals |
theory of indicators
Ostwald's theory of indicators | (chemistry) the theory that all indicators are either weak acids or weak bases in which the color of the ionized form is different from the color before dissociation |
| theory of inheritance | (biology) a theory of how characteristics of one generation are derived from earlier generations |
punctuated equilibrium
theory of punctuated equilibrium | a theory of evolution holding that evolutionary change in the fossil record came in fits and starts rather than in a steady process of slow change |
| quantum field theory | the branch of quantum physics that is concerned with the theory of fields, it was motivated by the question of how an atom radiates light as its electrons jump from excited states |
tectonics
plate tectonics
plate tectonic theory | the branch of geology studying the folding and faulting of the earth's crust |
associationism
association theory | (psychology) a theory that association is the basic principle of mental activity |
game theory
theory of games | (economics) a theory of competition stated in terms of gains and losses among opposing players |
philosophical doctrine
philosophical theory | a doctrine accepted by adherents to a philosophy |
political orientation
ideology political theory | an orientation that characterizes the thinking of a group or nation |
| domino theory | the political theory that if one nation comes under communist control then neighboring nations will also come under communist control |
guess
conjecture
supposition
surmise
surmisal
speculation hypothesis | a message expressing an opinion based on incomplete evidence |
| hypothesis | a proposal intended to explain certain facts or observations |