|Red and orange light waves have longer ____ than blue and violet.
|Coal, natural gas, and petroleum are types of ____.
|The process of a gas changing to a liquid is ____.
|A geyser is produced by ____ energy.
|Metals (silver, copper, gold, aluminum) are electric ____.
|Sound is transferred by ____ waves.
|Warm air rising from a heater is an example of ____.
|Light can pass through a ____ substance.