Science Glossary

alternating current - a circuit where the direction of the current switches back and forth (as opposed to direct current)

Ampere's law - an equation relating the electric current passing through a closed loop to the strength of the magnetic field pointing along that loop

amplitude - the maximum amount a wave oscillates, a.k.a. the intensity of the wave

atom - the building block of matter; contains a nucleus with protons and neutrons, which is surrounded by electrons

battery - a device that maintains a constant voltage that allows current to keep flowing

capacitor - two oppositely charged conductors some small distance apart; used in a circuit to temporarily store charge

cathode ray tube - a device that accelerates electrons and then magnetically deflects them onto different parts of a screen to create an image

conductor - a type of material that allows electric charge to flow freely through it; the opposite of an insulator

Coulomb's law - an equation describing the electric force between objects with electric charge

dielectric - material inserted in a capacitor to allow the capacitor to store more charge by reducing the electric field within it

dielectric breakdown - occurs when the voltage becomes too high for the dielectric to resist current flow within the capacitor, and the capacitor becomes discharged in a temporary big burst of current through the capacitor

diode - an element of an electric circuit that only allows current to flow through it in one direction; often used to convert alternating current to direct current

direct current - a circuit where current flows in one direction (as opposed to alternating current)

electric charge - a fundamental quantity of particles; determines how much the particle experiences electric and magnetic forces

electric circuit - a closed loop, typically with wire, that allows the continuous flow of current

electric current - the amount of charge flow, measured in amps (coulombs per second)

electric dipole - a configuration of charge with positive and negative charge separated by a short distance

electric field - a vector field created by a charged particle; tells other charges how to interact with it and points in the direction in which a charge will be accelerated at that position

electric field flux - amount of electric field passing through some area

electric force - otherwise known as Coulomb's law

electric polarization - refers to the separation of positive and negative charges within a neutral object; allows the object to feel electric forces

electric potential - the amount of energy per charge that a particle will experience traveling between two points; otherwise known as voltage

electric potential energy - the energy associated with an object's position in an electric field; can be converted into kinetic energy

electromagnetic force - the fundamental force that gives rise to both the electric and magnetic forces

electromagnetic wave - a wave of alternating electric and magnetic fields; such waves result in many effects, chief among them visible light.

electron - a particle within an atom; carries a negative charge; is the primary element of electricity

element - the different types of atoms on the Periodic Table, each with a different number of protons in its nucleus; a pure substance comprised of only one type of atom

Faraday's law - A changing magnetic field can generate a voltage in a wire without any other power source.

ferromagnetic - describes a material that can retain its own large-scale magnetic field; permanent magnets are made of such materials.

fundamental force - a force of nature between fundamental particles that cannot be broken down into anything simpler; there are four known fundamental forces in our universe.

gamma ray - a type of electromagnetic wave, mainly from nuclear reactions

Gauss's law - an equation relating the electric field flux through a closed surface around a charged object to the amount of charge enclosed by the surface

generator - a device that turns the energy of motion into electricity

gravitational field - a vector field that points toward massive objects, telling other massive objects to accelerate toward them via the gravitational force

gravitational force - a fundamental force that attracts mass to other mass

gravitational potential energy - the energy associated with an object's position in a gravitational field; can be converted into kinetic energy

inductor - a solenoid connected to a circuit to resist sudden changes in current

inertia - resistance to changes in motion; directly correlates to mass

infrared - a type of electromagnetic wave; mainly felt as heat from moderately warm objects

insulator - a type of material that does not allow electric charge to flow easily through it; the opposite of a conductor

inverse square law - a type of equation that describes a quantity that decreases with the square of the distance

ion - an atom that has an electric charge due to it having unequal numbers of protons and electrons

kinetic energy - the energy an object has due to its motion

length contraction - refers to the fact that due to the effects of relativity, something moving past you at very fast speeds will appear shorter in length than it would when stationary

Lenz's law - The current induced in a loop of wire by a changing magnetic field will create its own magnetic field to oppose the change.

longitudinal wave - a type of wave where the direction of oscillation is parallel to the direction of the wave motion, as opposed to a transverse wave

magnetic dipole - a north and south pole together; a dipole cannot be separated.

magnetic field - a vector field created by moving charges; a magnetic field will only affect moving charges.

magnetic field flux - the amount of magnetic field passing through some area

magnetic force - a force that deflects moving charges, steering them in a different direction without changing their speed

magnetic monopole - a hypothetical particle that has a north pole without a south pole, or vice versa; so far, no magnetic monopoles have been found.

mass - a fundamental quantity of particles; an object's mass determines its resistance to forces and how much it experiences gravitational forces.

Maxwell's equations - a set of four equations describing the behavior of electric and magnetic fields and how they relate to each other; these equations predict the existence of electromagnetic waves.

microwave - a type of electromagnetic wave; microwaves are used in microwave ovens and wireless communication.

motor - a device that takes electrical energy and causes something to move

neutron - a particle within the nucleus of an atom that is electrically neutral and so does not play a part in electricity

Newton's laws of motion - Newton's first law of motion

• An object will remain in constant motion unless acted upon by a force. Newton's second law of motion - An object feeling a force will accelerate in proportion to the force acting upon it and in inverse proportion to its mass. Newton's third law of motion

• An object exerting a force on another object will feel that same force back on itself from the other object.

  nucleus - the center of an atom; contains protons and neutrons

  Ohm's law - an equation that shows current is proportional to voltage and inversely proportional to resistance

  parallel circuit - when multiple objects are connected with wires in such a way that the current is split between them, as opposed to a series circuit

  paramagnetic - a material that can become magnetized when in the presence of a surrounding magnetic field but will not hold onto that magnetism permanently

  particle - a fundamental constituent of matter of which everything else is made

  power - the rate of energy change, measured in Watts

  proton - a particle within the nucleus of an atom; carries a positive charge

  radio wave- a type of electromagnetic wave; mainly used in wireless communication

  resistance - a quantity describing how much a material resists the flow of current

  scalar - a quantity with no direction (as opposed to a vector)

  scalar field - a quantity that has a scalar value at every point in space

  series circuit - when multiple objects are connected with wires in such a way that they share the same current, as opposed to a parallel circuit

  solenoid - a cylinder made of a wire looping around on top of itself multiple times

  superconductor - a material with zero resistance; so far, superconductors are only possible at extremely low temperatures.

  time dilation - refers to the fact that due to the effects of relativity, something moving past you at very fast speeds will appear to experience less time than you do

  transverse wave - a type of wave where the direction of oscillation is perpendicular to the direction of wave motion, as opposed to a longitudinal wave

  ultraviolet - a type of electromagnetic wave, commonly associated with getting a suntan or sunburn

  vector - a quantity with a magnitude and direction (as opposed to a scalar)

  vector field - a quantity with a vector value at every point in space

  voltage - the amount of energy per charge that a particle will experience traveling between two points; otherwise known as electric potential

  wave frequency - the number of times a wave oscillates per second

  wave polarization - the direction that an electromagnetic wave oscillates, compared to the direction it travels

  wavelength - the distance between the two crests of a wave

  X-ray - a type of electromagnetic wave; typically associated with high-energy chemical processes and medical imaging