1. Particle Theory of Matter
Heat
Particle Theory of Matter

2. Remember the Balloon Experiment?

3. The Heating Air Experiment
The balloon expanded when the bottle was put in hot water.
The balloon contracted when the bottle was taken out of the hot water.

4. Particle Theory is a theory which can explain what is happening.

5. Particle Theory of Matter
The Particle Theory of Matter explains heat and temperature.
It says all matter is made up of tiny particles too small to be seen.
These particles are always moving – they have energy.
The more energy they have, the faster they move.

6. If heat is added to a substance, the particles move faster.
If heat is taken away it moves slower.

7. So What About the Balloon?
The balloon inflated when the bottle was in hot water and deflated when the bottle was taken out.
This happened because the water’s heat caused the air molecules to move faster in the bottle and take up more room in the balloon.

8. Heat and Temperature Definitions
Heat is energy which transfers from hotter to colder substances.
Temperature is a measure of the average energy contained in the moving particles (ie. How much they are moving).

9. Another Example

10. Expansion and Contraction
When objects are heated, they have more energy and the particles move faster – taking up more space. This causes the substance to expand.
When objects cool, they have less energy and the particles move slower – taking up less space. This causes the substance to contract.
Heated Bottle Thermometer
Cooled Bottle Thermometer

11. Particle Theory and States of Matter
There are three states of matter: liquid, solid, and gas.
Particle Theory helps explain the difference between them.

12. Solid
Liquid
Gas
Movement
Particles vibrate in one spot.
Particles move freely around.
Particles move freely around and are separated by large spaces.
Flow
Has a rigid shape and does not flow.
Can flow and takes the shape of the container.
Volume
Has a set volume.
Fills any container.

13. A solid has a set volume and rigid shape. It does not flow
A solid has a set volume and rigid shape. It does not flow. Particles in a solid move but only by vibrating in one spot.
A liquid has a set volume, but takes the shape of its container. It can flow. Particles in a liquid are free to move around.
A gas fills any container it is in and takes on its shape. It can flow. Particles in a liquid are free to move around and are separated by large spaces.

14. Particle Theory and Changes of State
The changes between the states have names.

15. The temperature at which a solid melts (turns into a liquid) is called the melting point.
The temperature at which a liquid boils (turns to gas) is called the boiling point.

16. The states of matter change as you add energy.
The temperature remains constant during a change of state.

17. Energy (heat) added at the melting point is used to free particles from their set places in the solid state – not to make the particles move quicker. Therefore, the temperature does not rise.
Energy (heat) added at the boiling point is used to free particles from the surface of the liquid – not to make the particles move quicker. Therefore, the temperature does not rise.

19. Foldable Activity

20. Panels (front): Diagrams: Melting Boiling Condensing Freezing
Descriptions:
Heat is lost and particles stop moving around. They only vibrate. They become a solid.
Heat is used to free particles from their solid state. Freed particles are in liquid state.
Heat is used to free particles from the surface of the liquid. The freed particles are in the gas state.
Heat is lost and particles come closer together to form a liquid.

21. Heat Transfer Heat always moves from a warmer place to a cooler place.
Hot objects in a cooler room will cool to room temperature.
Cold objects in a warmer room will heat up to room temperature.

22. Heat transfers in three ways:
Conduction
Convection
Radiation

23. Conduction
Conduction is the transfer of heat by collisions between particles in the matter.
As matter is heated the particles vibrate more and collide with their neighbours – making them vibrate more. Heat is passed along the material.
Examples:
A spoon getting hit in hot water.
Accidentally touching a hot pan.

24. Conductors and Insulators
Some materials conduct heat very well. These are called conductors.
Some materials do NOT conduct heat very well. These are called insulators.

25. Convection
Convection is when heat transfers in a fluid (a liquid or gas) by the movement of particles from one place to another.
Examples:
Heat rising to the upper floors of a house.
A heater warming a room.
Opening a freezer and the cold mist coming out.

26. Radiation Radiation is the transfer of heat by electromagnetic waves.
Radiation does not need particles to occur.
Examples:
The sun heating the Earth.
Heat from a fire.

27. Heat Transfer Summary

28. Foldable Activity

29. Examples: Panels (front): Conduction Convection Radiation Definitions:
- A pan handle made of metal can heat up quickly.
Example:
- Homes are often heated this way. Warm air circulates through the house.
Example:
- The sun gives electromagnetic waves which transfer heat to the Earth.
Definitions:
Diagrams:
Definition:
- Heat transfer in a fluid by movement of heated particles from one place to another.
Definition:
- The transfer of energy by electromagnetic waves.
Definition:
- The transfer of heat by collisions between particles in solid matter.