| intake stroke | a mixture of gasoline and air enters a cylinder as the piston moves down |
| compression stroke | the mixture is squeezed into a smaller space as the piston moves back up |
| ignition | spark plug ignites mixture converting chemical energy to thermal energy making mixture a gas |
| power stroke | as the heated gas expands pushing down the piston thus the piston moves the crankshaft |
| exhaust stroke | crankshaft turns, and the piston is forced back up pushing exhaust gas out of the cylinder |
| thermostat | heat-regulating device |
| bimetallic strip | a strip consisting of two metals that bends with a rise in temperature |
| states | liquid, solid, and gas |
| freezing point | the temperature at which a liquid freezes |
| boiling point | Temperature at which a liquid boils |
| melting point | the temperature at which a solid becomes a liquid |
| refrigerator | a device that uses outside energy source to transfer thermal energy from a cool area to a warm area |
| external combustion engine | an engine powered by fuel burned outside the engine |
| internal combustion engine | an engine that burns fuel inside cylinders within the engine |
| insulator | a material that does not allow heat to move through it easily. |
| specific heat | the heat required to raise the temperature of one gram of a substance one degree kelvin |
| conduction | transfer of heat between particles within a substance |
| convection | the transfer of heat by the movement of currents within a fluid |
| radiation | the transfer of energy by electromagnetic waves |
| thermal expansion | the expansion of matter when heated |