Science Bowl Physics

Alpha Centauri

a double star, second closest to our sun, 4 light years away

Alpha Particle

2 protons and 2 neutrons particle

Ampere's Law

for any closed loop path, the sum of the length elements times the magnetic field in the direction of the length element is equal to the permeability times the electric current enclosed in the loop

AM Radio

uses the electrical image of a sound source to modulate the amplitude of a carrier wave. Between 535 kHz and 1605 kHz and the carrier waves are separated by 10 kHz

Archimedes Principle

The buoyant force on a submerged object is equal to the weight of the fluid displaced

Arctangent Problem

A common problem which arises in vector addition when the components of the resultant vector are found is that the arctan function in calculators and computer languages cannot distinguish the quadrant of the angle

Aspirator

A common device which makes use of the Bernoulli principle. When water is forced through a smooth constriction, the fluid velocity increases, lowering the pressure below atmospheric pressure

Asymptotic Freedom

As the quarks within a meson or baryon get closer together, the force of containment gets weaker so that it approaches zero for close confinement

Atwood's Machine

Application of Newton's second law to masses suspended over a pulley

Auger Effect

process by which electrons with characteristic energies are ejected from atoms in response to a downward transition by another electron in the atom

Automobile Hydraulic Lift

example of a force multiplied by hydraulic press, based on Pascal's principle. The fluid in the small cylinder must be moved much further than the distance the car is lifted.

Bag Model of Quark Confinement

In dealing with the nature of quark confinement, one visualization is that of an elastic bag which allows the quarks to move freely around, as long as you don't try to pull them further apart. But if you try to pull a quark out, the bag stretches and resists.

Ballistic Pendulum

a classic example of a dissipative collision in which conservation of momentum can be used for analysis, but conservation of energy during the collision cannot be invoked because the energy goes into inaccessible forms such as internal energy.

Bandwidth

The amount of data that can be transmitted over a network in a given amount of time.

Barnard's Star

A close star which is thought to have planets and exhibits proper motion. The variations in its position indicate the presence of at least one and probably more than one non-luminous body orbiting it.

Mercury Barometer

Pressure measurement device; The atmospheric pressure provides the force necessary to push the mercury up the evacuated tube

Baryons

massive particles which are made up of three quarks in the standard model. This class of particles includes the proton, neutron, lambda, sigma, xi, and omega particles.

Beat Frequency

the absolute value of the difference in frequency of the two waves; when two sound waves of different frequency approach your ear, the alternating constructive and destructive interference causes the sound to be alternatively soft and loud

Becquerel

amount of material which will produce 1 nuclear decay per second

Bernoulli's Principle

as the velocity of a fluid increases, the pressure exerted by the fluid decreases

Bimetallic Strips

A strip made of two different metals that expand at different rates (because of different thermal expansions). Made in coils to increase their sensitivity for use in thermostats

Nuclear Binding Energy

energy that holds the nucleus together. Can be calculated by mc^2

Biot-Savart Law

dB = (µ₀ I dI x r ̂ ) / 4πr²

-an equation that describes the magnetic field created by a current-carrying wire, and allows you to calculate its strength at various points.

-relates magnetic fields to the currents which are their sources.

Birefringent Materials

Crystalline materials may have different indices of refraction associated with different crystallographic directions. A common situation with mineral crystals is that there are two distinct indices of refraction, and they are called...

Blackbody Radiation

an object or system which absorbs all radiation incident upon it and re-radiates energy which is characteristic of this radiating system only, not dependent upon the type of radiation which is incident upon it

Boiling Point

the temperature at which the saturated vapor pressure of a liquid is equal to the surrounding atmospheric pressure

Boiling Water Reactor

the water which passes over the reactor core to act as moderator and coolant is also the steam source for the turbine. The disadvantage of this is that any fuel leak might make the water radioactive and that radioactivity would reach the turbine and the rest of the loop

Maxwell-Boltzmann Distribution

classical distribution function for distribution of an amount of energy between identical but distinguishable particles

Boltzmann's Constant

Gas Constant (R) divided by the Avogadro Constant: 1.38x10^-23

Bose-Einstein Condensation

Bosons are cooled to extremely low temperatures

Bose-Einstein Distribution

The statistical behavior of integer spin particles (bosons). At low temperatures, bosons can behave very differently than fermions because an unlimited number of them can collect into the same energy state, a phenomenon called "condensation".

Bosons

particles which have integer spin and which therefore are not constrained by the Pauli exclusion principle like the half-integer spins

Boyle's Law

PV=PV

Bragg's Law

A relationship that stipulates the condition for diffraction by a set of crystallographic planes.

nλ = 2dsinθ

Bragg Spectrometer

A basic instrument for x-ray diffraction studies

Breeder Reactor

A nuclear reactor in which more fissionable material is produced than is used up during operation.

Brehmsstrahlung radiation

the radiation which is emitted when electrons are decelerated or "braked" when they are fired at a metal target

Bulk Elastic Properties

determine how much it will compress under a given amount of external pressure

Calcite

widely used material in optics because of its birefringence. Its birefringence is so large that a crystal of this material placed over a dot on a page will reveal two distinct images of the dot

Specific Heat

the amount of heat per unit mass required to raise the temperature by one degree Celsius

Calorie

amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius

Calorimeter

Measures the quantity of heat exchanged. Used to determine the energy content of foods by burning the foods in an oxygen atmosphere and measuring the energy yield in terms of the increase in temperature of the device. They can also be used to measure the specific heat of a substance

Capillary Action

The result of adhesion and surface tension. Adhesion of water to the walls of a vessel will cause an upward force on the liquid at the edges and result in a meniscus which turns upward

Carrier

Radio transmission involves putting audio frequency information on a much higher frequency electromagnetic wave called a _________ wave

Carnot Cycle

The most efficient heat engine, comprised of two isothermal processes and two adiabatic processes. Highest efficiency allowed by physical laws.

Centrifugal Force

the outward force on a body moving in a curved path around another body

Coriolis Force

An apparent force created by the rotation of earth. Strongest at poles, weakest at equator.

Centripetal Force

Any motion in a curved path represents accelerated motion, and requires this force directed toward the center of curvature of the path

Charles's Law

TV=TV

The Charm Quark

third most massive quark, found in hadrons

Coherence

One of the unique properties of laser light. It arises from the stimulated emission process which provides the amplification. Since a common stimulus triggers the emission events which provide the amplified light, the emitted photons are "in step" and have a definite phase relation to each other

Color Force

the force between quarks, also, the source of the strong interaction

Compton Scattering

the scattering of a photon by a charged particle, usually an electron. It results in a decrease in energy (increase in wavelength) of the photon

Conduction

heat transfer by means of molecular agitation within a material without any motion of the material as a whole

Conjugate Points

The object point and image point of a lens system

Convection

heat transfer by mass motion of a fluid such as air or water when the heated fluid is caused to move away from the source of heat, carrying energy with it

Cooper Pairs

coupled electrons that can take the character of a boson and condense into the ground state

Cosmic Ray

high energy radiation which strikes the Earth from space. Intensity increases with altitude, showing that it comes from outer space

Cosmological Constant

initial motivation for this was to make possible a static universe which was isotropic and homogeneous

Curie Temperature

the temperature at which for a given ferromagnetic material, the long range order abruptly disappears

Current Law

The electric current in amperes that flows into any junction in an electric circuit is equal to the current which flows out

Cyclotron

one of the earliest types of particle accelerators, and is still used as the first stage of some large multi-stage particle accelerators. It makes use of the magnetic force on a moving charge to bend moving charges into a semicircular path between accelerations by an applied electric field.

Davisson- Germer experiment

This experiment demonstrated the wave nature of the electron, confirming the earlier hypothesis of deBroglie. Putting wave-particle duality on a firm experimental footing, it represented a major step forward in the development of quantum mechanics

Decibels

measure of sound intensity

DeBroglie Hypothesis

every particle that is moving has both a mass and a wave associated to it

Deuterium-Tritium Fusion

The most promising of the hydrogen fusion reactions which make up the deuterium cycle

Dewpoint

The temperature at which the moisture content in the air will saturate the air

Diamagnetism

Substances with no unpaired electrons are weakly repelled by a magnetic field. The residual magnetic behavior when materials are neither paramagnetic nor ferromagnetic.

Diffraction Grating

Is a flat plate which is opaque except for thousands of straight, parallel, equally spaced slits. Thin piece of material that bends light waves around microscopic slits, creating a rainbow. The tool of choice for separating the colors in incident light.

Diffraction

the bending of waves around small* obstacles and the spreading out of waves beyond small* openings.

Diffusion

the process by which molecules intermingle as a result of their kinetic energy of random motion

Doppler Effect

You hear the high pitch of the siren of the approaching ambulance, and notice that its pitch drops suddenly as the ambulance passes you

Down Quark

Second Lightest of all quarks. Joins with 2 up quarks to make a proton.

-1/3 charge

Law of Dulong and Petit

similarity in molar specific heats of metals is subject to this law

Einstein Velocity Addition

The relative velocity of any two objects never exceeds the velocity of light. Applying the Lorentz transformation to the velocities, expressions are obtained for the relative velocities as seen by the different observers.These expressions are called________

Electric Shock

electric current which passes through the body

electrolysis

splitting water into oxygen and hydrogen

Electromagnet

usually in the form of iron core solenoids. The ferromagnetic property of the iron core causes the internal magnetic domains of the iron to line up with the smaller driving magnetic field produced by the current in the solenoid. The effect is the multiplication of the magnetic field by factors of tens to even thousands

Electromagnetic Force

One of the four fundamental forces, manifests itself through the forces between charges (Coulomb's Law) and the magnetic force, it is an exchange force involving the exchange of photons

Electromagnetic Waves

transport energy through empty space, stored in propagating electric and magnetic fields

Ionization Energy

the energy necessary to remove an electron from the neutral atom

Electron Affinity

a measure of the energy change when an electron is added to a neutral atom to form a negative ion

Electron Capture

one form of radioactivity. A parent nucleus may capture one of its orbital electrons and emit a neutrino. This is a process which competes with positron emission and has the same effect on the atomic number

Electron Spin

s=1/2. It is an intrinsic property of electrons

Electron Volt

A convenient energy unit, particularly for atomic and nuclear processes, is the energy given to an electron by accelerating it through 1 volt of electric potential difference

Electronegativity

a measure of the ability of an atom in a molecule to draw bonding electrons to itself

Electroweak unification

The photon , the particle involved in the electromagnetic interaction, along with the W and Z provide the necessary pieces to unify the weak and electromagnetic interactions

Absorption of a Photon

will occur only when the quantum energy of the photon precisely matches the energy gap between the initial and final states

Enceladus

one of Saturn's 62+ moons and one of the most reflective bodies in the solar system. We learned a lot about it through the Cassini spacecraft

Entropy

nature tends to shift from order to disorder in isolated systems. A measure of disorder or randomness.

Equilibrium

Net Force=0, Net Torque=0, object moving with constant velocity or at rest

Equipartition of Energy

molecules in thermal equilibrium have the same average energy associated with each independent degree of freedom of their motion and that the energy is 3/2kT

Escape Velocity

If the kinetic energy of an object launched from the Earth were equal in magnitude to the potential energy. 25000 mph or 11.2km/s

Europa

One of Jupiter's moons, has a huge ocean under an ice layer, and has a young surface

Exchange Forces

The strong force transfers gluons, the electromagnetic force transfers photons, gravitational force= gravitons, Weak Force=W and Z bosons. Therefore, these forces are called_______

Fabry-Perot Interferometer

This interferometer makes use of multiple reflections between two closely spaced partially silvered surfaces. Part of the light is transmitted each time the light reaches the second surface, resulting in multiple offset beams which can interfere with each other

Faraday's Law

Any change in the magnetic environment of a coil of wire will cause a voltage (emf) to be "induced" in the coil. No matter how the change is produced, the voltage will be generated

Fermat's Principle

Light follows the path of least time

The Fermi-Dirac Distribution

a type of distribution function with a normalization term of e to the power of -EF/kT where EF=Fermi Energy

Fermi Level

the top of the collection of electron energy levels at absolute zero temperature