| A | B |
|---|
| atom | the smallest unit of an element that has all the properties of that |
| chemical change | changes in matter in which one or more new substances are formed |
| condensation | the process by which a gas changes into a liquid |
| electric charge | the charge obtained by an object when it gains or loses electrons |
| electric circuit | the path along which electrons flow |
| electrical energy | energy of moving electrons |
| energy | the ability to cause changes in matter |
| evaporation | the process by which a liquid changes into a gas |
| force | a push or a pull on an object—can cause an object to move, change |
| friction | a force that acts against motion when two surfaces rub against each |
| gas | matter with no definite shape or volume |
| gravity | a force that pulls all objects in the universe toward one another |
| liquid | Matter that has a definite volume but takes the shape of its |
| mass | the amount of matter in an object |
| matter | anything that has mass and takes up space |
| mechanical energy | energy that puts something in motion |
| mixture | a combination of two or more different kinds of matter, each of |
| molecule | a grouping of two or more atoms joined together |
| nuclear energy | energy locked in the nucleus of an atom |
| physical change | a special type of mixture in which particles of the two substances |
| pitch | how high or low a sound is as determined by the frequency |
| precipitation | any form of water that falls from clouds such as rain or snow |
| radiant energy | energy that moves in waves |
| reflection | the bouncing of light (or sound) off objects |
| refraction | the bending of light rays when they pass from one substance into a |
| solid | matter that has a definite shape and volume |
| solution | a special type of mixture in which particles of the two substances |
| sound | the movement of energy through substances in longitudinal waves |
| thermal energy | heat energy; energy of moving molecules |
| vibration | rapid back and forth movement of matter that produces sound |
| volume | the loudness of a sound |
| weight | the measure of the force of gravity on an object |
| work | the use of force to move an object through a distance |
