Page 30 - Science Course 1 (Book 2)
P. 30
Mo7-L3a: What is Physical Change?
As thermal energy is added to a material, temperature increases when the state of the material is not chang-
ing. Temperature stays the same during a change of state.
When thermal energy is removed from a gas, After the gas has completely changed to a liquid,
particles in the gas move more slowly and the removing more thermal energy from the liquid
temperature decreases. causes particles move even more slowly.
Condensation occurs when the particles are Freezing occurs when the particles are moving so
moving slowly enough for attractive forces to pull slowly that attractive forces between the particles
the particles close together. hold them tightly together.
gas
Getting Hotter evaporating condensing Getting Colder
liquid
freezing
melting
Deposition is the change from a gas directly to a
solid solid.
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