Scholastic Bowl Science Laws and Theories

Ampere's Law

The line integral of the magnetic flux around a closed curve is proportional to the algebraic sum of electric currents flowing through that closed curve

Archimedes' Principle

A body that is submerged in a fluid is buoyed up by a force equal in magnitude to the weight of the fluid that is displaced, and directed upward along a line through the center of gravity of the displaced fluid

Avogadro's Law

Equal volumes of all gases at the same temperature and pressure contain equal numbers of molecules

Bernoulli's Principle

An increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy; In an irrotational fluid, the sum of the static pressure, the weight of the fluid per unit mass times the height, and half the density times the velocity squared is constant throughout the fluid

Boyle's Law

The product of the pressure and the volume of an ideal gas at constant temperature is a constant

Bragg's Law

When a beam of X-rays strikes a crystal surface in which the layers of atoms or ions are regularly separated, the maximum intensity of the reflected ray occurs when the complement of the angle of incidence, theta, the wavelength of the X-rays, lambda, and the distance between layers of atoms or ions, d, are related by the equation 2 d sin theta = n lambda

Brownian Motion

The continuous random motion of solid microscopic particles when suspended in a fluid medium due to the consequence of ongoing bombardment by atoms and molecules

Casimir Effect

A quantum mechanical effect, where two very large plates placed close to each other will experience an attractive force, in the absence of other forces. The cause is virtual particle-antiparticle pair creation in the vicinity of the plates. Also, the speed of light will be increased in the region between the two plates, in the direction perpendicular to them

Causality Principle

The principle that cause must always preceed effect. More formally, if an event A ("the cause") somehow influences an event B ("the effect") which occurs later in time, then event B cannot in turn have an influence on event A. That is, event B must occur at a later time t than event A, and further, all frames must agree upon this ordering

Centrifugal Force

A pseudoforce on an object when it is moving in uniform circular motion. The "force" is directed outward from the center of motion

Centripetal Force

A force on an object when it is moving in uniform circular motion. The "force" is directed inward towards the center of motion

Charles' Law

The volume of an ideal gas at constant pressure is proportional to the thermodynamic temperature of that gas

Cherenkov Radiation

Radiation emitted by a massive particle which is moving faster than light in the medium through which it is traveling. No particle can travel faster than light in vacuum, but the speed of light in other media, such as water, glass, etc., are considerably lower

Complementarity Principle

The principle that a given system cannot exhibit both wave-like behavior and particle-like behavior at the same time. That is, certain experiments will reveal the wave-like nature of a system, and certain experiments will reveal the particle-like nature of a system, but no experiment will reveal both simultaneously

Compton Effect

An effect that demonstrates that photons (the quantum of electromagnetic radiation) have momentum. A photon fired at a stationary particle, such as an electron, will impart momentum to the electron and, since its energy has been decreased, will experience a corresponding decrease in frequency

Constancy Principle

One of the postulates of A. Einstein's special theory of relativity, which puts forth that the speed of light in vacuum is measured as the same speed to all observers, regardless of their relative motion

Continuity Equation

An equation which states that a fluid flowing through a pipe flows at a rate which is inversely proportional to the cross-sectional area of the pipe. It is in essence a restatement of the conservation of mass during constant flow

Heliocentric Theory

The idea, suggested by Copernicus, that the Sun, not the Earth, is at the center of the Universe

Coriolis Effect

A pseudoforce which arises because of motion relative to a frame of reference which is itself rotating relative to a second, inertial frame

Correspondence Principle

The principle that when a new, more general theory is put forth, it must reduce to the more specialized (and usually simpler) theory under normal circumstances

Coulomb's Law

The primary law for electrostatics, analogous to Newton's law of universal gravitation. It states that the force between two point charges is proportional to the algebraic product of their respective charges as well as proportional to the inverse square of the distance between them

Dalton's Law of Partial Pressures

The total pressure of a mixture of ideal gases is equal to the sum of the partial pressures of its components; that is, the sum of the pressures that each component would exert if it were present alone and occupied the same volume as the mixture

Doppler Effect

Waves emitted by a moving object as received by an observer will be blueshifted (compressed) if approaching, redshifted (elongated) if receding. It occurs both in sound as well as electromagnetic phenomena

Equivalence Principle

The basic postulate of A. Einstein's general theory of relativity, which posits that an acceleration is fundamentally indistinguishable from a gravitational field

Faraday's Law

The line integral of the electric field around a closed curve is proportional to the instantaneous time rate of change of the magnetic flux through a surface bounded by that closed curve

Fermat's Principle

The principle states that the path taken by a ray of light between any two points in a system is always the path that takes the least time

Guass' Law

The electric flux through a closed surface is proportional to the algebraic sum of electric charges contained within that closed surface

Hall Effect

When charged particles flow through a tube which has both an electric field and a magnetic field (perpendicular to the electric field) present in it, only certain velocities of the charged particles are preferred, and will make it un-deviated through the tube; the rest will be deflected into the sides

Hooke's Law

The stress applied to any solid is proportional to the strain it produces within the elastic limit for that solid (usually for springs). The constant of that proportionality is the Young modulus of elasticity for that substance

Huygens' Principle

The mechanical propagation of a wave (specifically, of light) is equivalent to assuming that every point on the wavefront acts as point source of wave emission

Ideal Gas Law

PV = nRT

Kohlrausch's Law

If a salt is dissolved in water, the conductivity of the solution is the sum of two values -- one depending on the positive ions and the other on the negative ions

Lambert's Laws

The illuminance on a surface illuminated by light falling on it perpendicularly from a point source is proportional to the inverse square of the distance between the surface and the source

If the rays meet the surface at an angle, then the illuminance is proportional to the cosine of the angle with the normal

The luminous intensity of light decreases exponentially with distance as it travels through an absorbing medium

Lenz's Law

An induced electric current always flows in such a direction that it opposes the change producing it

Nernst Equation

An equation that relates the reduction potential of a half-cell (or the total voltage, i.e. the electromotive force, of the full cell) at any point in time to the standard electrode potential, temperature, activity, and reaction quotient of the underlying reactions and species used

Lorentz Force

The combination of electric and magnetic force on a point charge due to electromagnetic fields

Mach Number

The ratio of the speed of an object in a given medium to the speed of sound in that medium

Mach's Principle

The inertia of any particular particle or particles of matter is attributable to the interaction between that piece of matter and the rest of the Universe. Thus, a body in isolation would have no inertia

Murphy's Law

If anything can go wrong, it will

Newton's Law of Universal Gravitation

Two bodies attract each other with equal and opposite forces; the magnitude of this force is proportional to the product of the two masses and is also proportional to the inverse square of the distance between the centers of mass of the two bodies

Kepler's Laws of Planetary Motion

1) The orbit of a planet is an ellipse with the Sun at one of the two foci

2) A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time

3) The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit

Newton's Laws of Motion

An object will continue in its state of constant striaghtline velocity, which may be zero, unless acted upon by an unequal external force

F = ma

For every action there is an equal and opposite reaction

Occam's Razor

If two theories predict phenomena to the same accuracy, then the one which is simpler is the better one

Ohm's Law

The ratio of the potential difference between the ends of a conductor to the current flowing through it is constant; the constant of proportionality is called the resistance, and is different for different materials

Pascal's Principle

Pressure applied to an enclosed incompressible static fluid is transmitted undiminished to all parts of the fluid

Planck Equation

The quantum mechanical equation relating the energy of a photon E to its frequency; E = hv

Reflection Law

For a wavefront intersecting a reflecting surface, the angle of incidence is equal to the angle of reflection, in the same plane defined by the ray of incidence and the normal

Snell's Law

Also known as the law of refraction; the sine of angle of incidence times the index of refraction for that specific medium through which waves are travelling is equal to the sine of the angle of refraction times the index of refraction for the other medium

Relativity Principle

The principle, employed by Einstein's relativity theories, that the laws of physics are the same, at least qualitatively, in all frames. That is, there is no frame that is better (or qualitatively any different) from any other

Superposition Principle

The general idea that, when a number of influences are acting on a system, the total influence on that system is merely the sum of the individual influences

Laws of Thermodynamics

The change in internal energy of a system is the sum of the heat transferred to or from the system and the work done on or by the system

The entropy -- a measure of the unavailability of a system's energy to do useful work -- of a closed system tends to increase with time

For changes involving only perfect crystalline solids at absolute zero, the change of the total entropy is zero

Uncertainty Principle

A principle, central to quantum mechanics, which states that two complementary parameters (such as position and momentum, energy and time, or angular momentum and angular displacement) cannot both be known to infinite accuracy; the more you know about one, the less you know about the other

van der Waals Forces

Forces responsible for the non-ideal behavior of gases, and for the lattice energy of molecular crystals. There are three causes: dipole-dipole interaction; dipole-induced dipole moments; and dispersion forces arising because of small instantaneous dipoles in atoms

Wave-Particle Duality

The principle of quantum mechanics which implies that light (and, indeed, all other subatomic particles) sometimes act like a wave, and sometime act like a particle, depending on the experiment you are performing. For instance, low frequency electromagnetic radiation tends to act more like a wave than a particle; high frequency electromagnetic radiation tends to act more like a particle than a wave

Photoelectric Effect

The observation that many metals emit electrons when light shines upon them. Electrons emitted in this manner can be called photoelectrons. According to classical electromagnetic theory, this effect can be attributed to the transfer of energy from the light to an electron in the metal

De Morgan's Law

The negation of a conjunction is the disjunction of the negations.

The negation of a disjunction is the conjunction of the negations

"not (A and B)" is the same as "(not A) or (not B)"

"not (A or B)" is the same as "(not A) and (not B)"

Maxwell-Boltzmann Distribution

describes particle speeds in idealized gases where the particles move freely inside a stationary container without interacting with one another, except for very brief collisions in which they exchange energy and momentum with each other or with their thermal environment

Hund's Rule

Every orbital in a sublevel is singly occupied before any orbital is doubly occupied

All of the electrons in singly occupied orbitals have the same spin (to maximize total spin)

Beer's Law

Relates the absorbance of light as directly related to its concentration and path length and its molar absorbtivity constant; A = abc

Henderson-Hasselbalch Equation

Relates the pH of a solution to the acid dissociation constant pKa and the ratio of conjugate base to an acid; used to estimate the pH of a buffer solution and finding the equilibrium pH in acid-base reactions

Schrodinger Equation

Describes how the wavefunction of a physical system evolves over time

Arrhenius Equation

Relates the rate constant of a chemical reaction to the activation energy and temperature at which the reaction occurs

Hess' Law

States that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes; enthalpy is independent of the pathway taken

Graham's Law of Effusion

The relative rates of effusion of two gasses are equal to the inverse of the square roots of thier masses

Henry's Law

The amount of a gas dissolved in a solution is directly proportional to the pressure of the gas above the solution

Raoult's Law

States that the partial vapour pressure of each component of an ideal mixture of liquids is equal to the vapor pressure of the pure component multiplied by its mole fraction in the mixture

Le Chatelier's Principle

If a change is imposed on a system at equilibrium, the position of the equilibrium will shift in a direction that tends to reduce that change

Van't Hoff Equation

Relates the change in the equilibrium constant, Keq, of a chemical equilibrium to the change in temperature, T, given the standard enthalpy change, ΔH

Pauli Exclusion Principle

Two electrons that occupy the same orbital must have opposite spins; No two electrons in a single atom can have the same set of four quantum numbers

Aufbau Principle

States that in the ground state of an atom, an electron enters the orbital with lowest energy first and subsequent electrons are fed in the order of increasing energies