types:
all-or-none law
(neurophysiology) a nerve impulse resulting from a weak stimulus is just as strong as a nerve impulse resulting from a strong stimulus
principle,
rule
a rule or law concerning a natural phenomenon or the function of a complex system
Bernoulli's law,
law of large numbers
(statistics) law stating that a large number of items taken at random from a population will (on the average) have the population statistics
Benford's law
a law used by auditors to identify fictitious populations of numbers; applies to any population of numbers derived from other numbers
Bose-Einstein statistics
(physics) statistical law obeyed by a system of particles whose wave function is not changed when two particles are interchanged (the Pauli exclusion principle does not apply)
Coulomb's Law
a fundamental principle of electrostatics; the force of attraction or repulsion between two charged particles is directly proportional to the product of the charges and inversely proportional to the distance between them; principle also holds for magnetic poles
Dalton's law,
Dalton's law of partial pressures,
law of partial pressures
(chemistry and physics) law stating that the pressure exerted by a mixture of gases equals the sum of the partial pressures of the gases in the mixture; the pressure of a gas in a mixture equals the pressure it would exert if it occupied the same volume alone at the same temperature
distribution law
(chemistry) the total energy in an assembly of molecules is not distributed equally but is distributed around an average value according to a statistical distribution
equilibrium law,
law of chemical equilibrium
(chemistry) the principle that (at chemical equilibrium) in a reversible reaction the ratio of the rate of the forward reaction to the rate of the reverse reaction is a constant for that reaction
Fechner's law,
Weber-Fechner law
(psychophysics) the concept that the magnitude of a subjective sensation increases proportional to the logarithm of the stimulus intensity; based on early work by E. H. Weber
Fermi-Dirac statistics
(physics) law obeyed by a systems of particles whose wave function changes when two particles are interchanged (the Pauli exclusion principle applies)
Henry's law
(chemistry) law formulated by the English chemist William Henry; the amount of a gas that will be absorbed by water increases as the gas pressure increases
Hooke's law
(physics) the principle that (within the elastic limit) the stress applied to a solid is proportional to the strain produced
Hubble law,
Hubble's law
(astronomy) the generalization that the speed of recession of distant galaxies (the red shift) is proportional to their distance from the observer
Kirchhoff's laws
(physics) two laws governing electric networks in which steady currents flow: the sum of all the currents at a point is zero and the sum of the voltage gains and drops around any closed circuit is zero
law of averages
a law affirming that in the long run probabilities will determine performance
law of diminishing returns
a law affirming that to continue after a certain level of performance has been reached will result in a decline in effectiveness
law of effect
(psychology) the principle that behaviors are selected by their consequences; behavior having good consequences tends to be repeated whereas behavior that leads to bad consequences is not repeated
Newton's law of gravitation,
law of gravitation
(physics) the law that states any two bodies attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them
Dalton's law,
law of multiple proportions
(chemistry) law stating that when two elements can combine to form more than one compound the amounts of one of them that combines with a fixed amount of the other will exhibit a simple multiple relation
law of mass action
(chemistry) the law that states the following principle: the rate of a chemical reaction is directly proportional to the molecular concentrations of the reacting substances
law of thermodynamics
(physics) a law governing the relations between states of energy in a closed system
Mendel's law
(genetics) one of two principles of heredity formulated by Gregor Mendel on the basis of his experiments with plants; the principles were limited and modified by subsequent genetic research
Ohm's law
electric current is directly proportional to voltage and inversely proportional to resistance; I = E/R
Pascal's law,
Pascal's law of fluid pressures
pressure applied anywhere to a body of fluid causes a force to be transmitted equally in all directions; the force acts at right angles to any surface in contact with the fluid
Mendeleev's law,
periodic law
(chemistry) the principle that chemical properties of the elements are periodic functions of their atomic numbers
Planck's law
(physics) the basis of quantum theory; the energy of electromagnetic waves is contained in indivisible quanta that have to be radiated or absorbed as a whole; the magnitude is proportional to frequency where the constant of proportionality is given by Planck's constant
Planck's radiation law
(physics) an equation that expresses the distribution of energy in the radiated spectrum of an ideal black body
principle of relativity
(physics) a universal law that states that the laws of mechanics are not affected by a uniform rectilinear motion of the system of coordinates to which they are referred
Weber's law
(psychophysics) the concept that a just-noticeable difference in a stimulus is proportional to the magnitude of the original stimulus
Kepler's first law
a law stating that the orbit of each planet is an ellipse with the sun at one focus of the ellipse
Kepler's third law,
harmonic law
a law stating that the ratio of the square of the revolutionary period (in years) to the cube of the orbital axis (in astronomical units) is the same for all planets
second law of thermodynamics
a law stating that mechanical work can be derived from a body only when that body interacts with another at a lower temperature; any spontaneous process results in an increase of entropy
zeroth law of thermodynamics
the law that if two bodies are in thermal equilibrium with a third body then the first two bodies are in thermal equilibrium with each other
Gresham's Law
(economics) the principle that when two kinds of money having the same denominational value are in circulation the intrinsically more valuable money will be hoarded and the money of lower intrinsic value will circulate more freely until the intrinsically more valuable money is driven out of circulation; bad money drives out good; credited to Sir Thomas Gresham
law of segregation
members of a pair of homologous chromosomes separate during the formation of gametes and are distributed to different gametes so that every gamete receives only one member of the pair
law of independent assortment
each member of a pair of homologous chromosomes separates independently of the members of other pairs so the results are random
mass-energy equivalence
(physics) the principle that a measured quantity of mass is equivalent (according to relativity theory) to a measured quantity of energy
Naegele's rule
rule for calculating an expected delivery date; subtract three months from the first day of the last menstrual period and add seven days to that date
principle of equivalence
(physics) the principle that an observer has no way of distinguishing whether his laboratory is in a uniform gravitational field or is in an accelerated frame of reference
mass action,
mass-action principle
(neurology) the principle that the cortex of the brain operates as a coordinated system with large masses of neural tissue involved in all complex functioning