Front

What is density?

Back

The compactness of atoms in a substance.

Front

Why might a door stick on a hot day?

Back

The door material expands in heat.

Front

What happens to the motion of atoms when heat is applied?

Back

They move faster.

Front

What is the difference between evaporation and boiling?

Back

Evaporation occurs at the surface, boiling occurs throughout the liquid.

Front

What does adding heat do to the volume of objects?

Back

Objects expand.

Front

What is thermal expansion?

Back

The increase in volume of a substance due to an increase in temperature.

Front

What is the formula for density?

Back

Density = Mass/Volume.

Front

What happens to the density of most substances when heated?

Back

The density decreases.

Front

What is the boiling point?

Back

The temperature at which a liquid turns into vapor.

Front

What is evaporation?

Back

The process by which molecules at the surface of a liquid escape into the gas phase.