What is needed to change a solid into a liquid?

• Pressure

• Cold

• Heat

• Light

What is the process called when a solid turns directly into a gas?

• Condensation

• Melting

• Freezing

• Sublimation

What happens to water molecules when they freeze?

• They move faster

• They take up more space

• They disappear

• They become gas

What is the term for a gas turning into a liquid?

• Boiling

• Sublimation

• Fusion

• Condensation

What is the freezing point of oxygen at standard pressure?

• -218.8 degrees Celsius

• 0 degrees Celsius

• 100 degrees Celsius

• -100 degrees Celsius