1. How matter changes forms
State Changes
How matter changes forms

2. Changing states
Matter can change from one state to another when heat energy is released or absorbed. Although its physical state may change, its chemical state remains the same.
This is called a change of state.

3. State Change Pyramid Gas Liquid Solid Melting Absorbing Releasing
thermal energy
Releasing
thermal energy
Gas
Melting
Liquid
Solid

4. Melting
The change from the solid state to the liquid state is melting.
The temperature at which a substance changes from a solid to a liquid is called the melting point.
Melting is when matter absorbs heat energy, and its temperature rises.

5. State Change Pyramid Gas Liquid Solid Melting Freezing Absorbing
thermal energy
Releasing
thermal energy
Gas
Melting
Freezing
Liquid
Solid

6. Freezing
The change from the liquid state to the solid state is called freezing.
The temperature at which a substance changes from the liquid state to the solid state is called the freezing point.
Energy is released during freezing.

7. State Change Pyramid Gas Liquid Solid Evaporation Melting Freezing
Absorbing
thermal energy
Releasing
thermal energy
Gas
Evaporation
Melting
Freezing
Liquid
Solid

8. Evaporation
The change from the liquid state to a gas state is known as evaporation.
The temperature at which a liquid boils is called the boiling point.

9. State Change Pyramid Gas Liquid Solid Condensation Evaporation Melting
Absorbing
thermal energy
Releasing
thermal energy
Gas
Condensation
Evaporation
Melting
Freezing
Liquid
Solid

10. Condensation As a gas cools, its particles slow down.
The process of a gas changing to a liquid is called condensation.
This process is the opposite of evaporation.

11. State Change Pyramid Gas Liquid Solid Condensation Sublimation
Absorbing
thermal energy
Releasing
thermal energy
Gas
Condensation
Sublimation
evaporation
Melting
Freezing
Liquid
Solid

12. Sublimation
Some substances can change from the solid state to the gas state without ever becoming a liquid.
This process is known as sublimation.
Picture from

16.  Particles slide past each other
 Definite shape
 No definite volume
 Definite volume
 Particles close together
 No definite shape
 Particles move quickly
Melting
 Boiling
 Condensation
 Freezing
 Evaporation
 Sublimation