Science 7
Notes 11
Phases of Matter
Melting
Freezing
Vaporization
Condensation
Sublimation
Can you describe the phase
changes that matter
undergoes?
1. Characteristics of a Phase Change
What is
necessary for a
phase change to
occur?
• It’s a change from one state of matter (solid, liquid, gas) to another.
• Phase changes are physical changes because:
- It only affects physical appearance, not chemical make-up.
What are the
states of matter?
- They are Reversible
2. What happens during a phase change?

What particle
changes are
evident when
heat is added to a
substance?
What particle
changes are
evident when
heat is removed
from a
substance?
During a phase change, heat energy is either absorbed or released.
o Heat energy is released as molecules slow down and move
closer together.
o Heat energy is absorbed as molecules speed up and expand.
3. Types of Phase Changes
A. Melting

Phase change from a solid to a liquid

Molecules speed up, move farther apart, and absorb heat
energy
Describe melting.
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Science 7
What states of
matter change
during freezing?
Notes 11
B. Freezing

Phase Change from a liquid to a solid

Molecules slow down, move closer
together and release heat energy.
How does
molecular
movement
change during
freezing?
What states of
matter change
during
vaporization?
How does
molecular
movement
change during
vaporization?
C. Vaporization/Evaporation

Phase change from a liquid to a gas.

Vaporization occurs throughout and happens at the
boiling point. Evaporation happens on the surface of a
liquid at any temperature.

Molecules speed up, move farther apart, and absorb heat
energy.
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Science 7
Notes 11
D. Condensation

Phase change from a gas to a liquid.

Molecules slow down, move closer together and release
heat energy.
E. Sublimation

Phase change from a solid to a gas.

Molecules speed up, move farther apart, and absorb heat
energy.
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