| A | B |
|---|
| friction | rubbing |
| fuel | material that is burned to produce heat energy |
| heat | a form of energy that we can feel |
| conduction | movement of heat energy by molecules bumping into each other |
| convection | the way that heat travels through gases and liquids |
| convection currents | up-and-down movements of gases or liquids caused by convection |
| radiation | the way that heat energy travels through space |
| radiometer | a device that turns when sunlight shines on it |
| solar cell | a device that produces electricity when sunlight shines on it |
| expand | get larger; take up more space |
| contract | get smaller; take up less space |
| temperature | a measure of how hot a material is |
| thermometer | a tool used to measure temperature |
| degree | a unit of temperature |
| Fahrenheit scale | the temperature scale in which the freezing point is 212º |
| Celsius scale | the temperature scale in which the freezing point of water is 0º and the boiling point is 100º |
| calorie | a unit of hear; the amount of heat needed to raise the temperature of 1 gram of water 1º C |
| Calorie | a large calorie; 1000 calories |
