Unit 3 Science Vocab

Specific heat capacity

The quantity of heat required to change the temperature of a unit mass of a substance by 1 degree Celsius.

Joule

SI unit for energy (or heat).

Kelvin

SI unit for temperature.

Temperature

The average kinetic energy per molecule in a system.

Thermal energy

The total amount of kinetic energy of the molecules in a system.

Weather

The current state of the atmosphere.

Kinetic energy

Energy an object possesses due to its motion and mass.

Absolute zero

The lowest possible temperature that a substance may have — the molecules have their minimum kinetic energy.

Climate

The characteristic weather patterns in an area over a long period of time.

Heat

The measurement of energy in transit between a system with higher kinetic energy to one of lower kinetic energy.

Greenhouse effect

Warming of a planet's lower atmosphere, due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation emitted from the planet's surface.

Radiation

The transfer of energy by means of electromagnetic waves.

Newton’s law of cooling

The rate of heat loss from an object is proportional to the temperature difference between the object and its surroundings.

Frequency

For a wave, the number of crests that pass a particular point each second.

Conduction

The transfer of heat energy by molecular and electron collisions within a substance (especially a solid).

Wavelength

The distance between successive crests, troughs, or identical parts of a wave.

Convection

The transfer of heat energy in a gas or liquid by means of currents in the heated fluid.

Ionization

The change of phase from gaseous to plasma.

Regelation

The process of melting under pressure and the subsequent refreezing when the pressure is removed.

Condensation

The change of phase from gaseous to liquid.

Boiling

Rapid evaporation that takes place within a liquid as well as at its surface.

Sublimation

The change of phase from solid to gaseous, skipping the liquid phase.

Deionization

The change of phase from plasma to gaseous.

Deposition

The change of phase from gaseous to solid, skipping the liquid phase.

Melting

The change of phase from solid to liquid.

Evaporation

The change of phase from liquid to gaseous.

Freezing

The change of phase from liquid to solid.

Internal energy

The total of all molecular energies, kinetic plus potential, that are internal to a system.

Adiabatic process

A process, often of fast expansion or compression, wherein no heat enters or leaves a system.

1st law of thermodynamics

Energy can neither be created nor destroyed.

Thermodynamics

The study of heat and its transformation to different forms of energy.

Isobar

A line on a weather map that connects places that have the same atmospheric pressure.

Front

A boundary or transition zone between two air masses with different properties, such as temperature and humidity.

Atmospheric pressure

The force per unit area exerted against a surface by the weight of the air above that surface.

2nd law of thermodynamics

Thermal energy never spontaneously flows from a cold object to a hot object.

Air mass

A large body of air with roughly the same temperature and moisture conditions throughout.

Standing Wave

A stationary wave pattern formed in a medium when two sets of identical waves pass in opposite directions.

Transverse Wave

A wave in which the medium vibrates in a direction perpendicular to the direction in which the wave travels.

Longitudinal Wave

A wave in which the medium vibrates in a direction parallel to the direction in which the wave travels.

Amplitude

For a wave or vibration, the maximum displacement on either side of the equilibrium (midpoint) position.

Period

The time in which a full vibration or wave oscillation is completed.

Superposition Principle

The displacement due to the interference of waves is determined by adding the disturbances produced by each wave.

Hertz

The SI unit for frequency. It equals one vibration per second.

Doppler Effect

The shift in received frequency due to motion of a vibrating source toward or away from a receiver.

Reflection

The return of light, heat, sound, or energy from a surface.

Compression

Region of higher density and pressure in the medium through which a longitudinal wave travels.

Resonance

A phenomenon in which the frequency of forced vibrations on an object matches the object’s natural frequency.

Rarefaction

Region of lower density and pressure in the medium through which a longitudinal wave travels.

Refraction

The change in direction of a wave passing from one medium to another caused by its change in speed.

Ultrasonic

A sound that has a frequency too high to be heard by the normal human ear.

Insulator

A material without free charged particles and through which charge does not easily flow.

Electrically polarized

Term applied to an atom or molecule in which the charges separate causing one side to be slightly more positive and the other to be slightly more negative.

Conservation of Charge

Electric charge is neither created nor destroyed. The total charge before an interaction equals the total charge after.

Coulomb

The SI unit for electrical charge (symbol C) is equal to the total charge of 6.25 x 10^18 electrons.

Electric potential energy

Energy possessed by a charged particle due to its location in an electric field.

Conductor

Any material having free charged particles that easily flow through it when an electric force acts on them.

Coulomb’s law

Like charges repel and opposite charges attract, with a force proportional to the product of the charges and inversely proportional to the square of the distance between them.

Electric potential

The electric potential energy per unit of charge, measured in volts, and often called voltage.

Electrostatics

The study of electric charge at rest (not in motion, as in electric current).

Electric field

A region around a charged particle or object within which a force would be exerted on other charged particles or objects.

Electric Current

The rate at which electric charge flows and transports energy.

Semiconductor

A substance that can act as an electrical conductor or insulator depending on chemical changes or external conditions.

Voltage

The difference in electric potential between two points (potential difference).

Resistance

The property of a material that resists electric current.

Ohm’s Law

The current in a circuit is directly proportional to the voltage and inversely proportional to the resistance.

Parallel Circuit

An electric circuit or path with branches so that the current divides and only part of it flows through any branch.

Alternating Current (AC)

Flow of electric charge that periodically reverses.

Series Circuit

An electric circuit or path along which the whole current flows through each component.

Electric Power

The amount of energy per unit time, measured by the product of current and voltage.

Direct Current (DC)

Electric charge that is flowing in one direction only.