1. The Particle Theory, Temperature and Thermal Energy

2. Questions How does a material change when it is warmed or cooled? How does a material change when it is warmed or cooled? How does warming and cooling affect the tiny particles of which everything is made? How does warming and cooling affect the tiny particles of which everything is made?

3. The Particle Theory of Matter Notes All substances are made up of tiny particles All substances are made up of tiny particles The particles are always in motion- vibrating, rotating and (in liquids and gases) moving from place to place The particles are always in motion- vibrating, rotating and (in liquids and gases) moving from place to place

4. Notes When the temperature of a substance changes, the motion of the particles change as well When the temperature of a substance changes, the motion of the particles change as well When a substance warms…. It’s temperature increases….and its particles…. When a substance warms…. It’s temperature increases….and its particles…. Move faster Move faster

5. Notes When a substance cools…. Its temperature decreases….. And its particles move… When a substance cools…. Its temperature decreases….. And its particles move… More slowly! More slowly!

6. Scientists It is hard to test this theory directly because the particles that make up everything are too small to be seen. The best scientists can do is observe large groups of particles to get an idea about what happens It is hard to test this theory directly because the particles that make up everything are too small to be seen. The best scientists can do is observe large groups of particles to get an idea about what happens Therefore, temperature indicates the average speed of particle motion in a substance Therefore, temperature indicates the average speed of particle motion in a substance

7. Assignment List the main points of the particle theory of matter that were presented. List the main points of the particle theory of matter that were presented. Why is it hard to test the particle theory of matter? Why is it hard to test the particle theory of matter? What happens to the particles in a substance when its temperature increases? What happens to the particles in a substance when its temperature increases? When the particles of a substance slow down, what is happening to the temperature? When the particles of a substance slow down, what is happening to the temperature?

8. Energy Energy is a measurement of something’s ability to cause changes or to make something else move Energy is a measurement of something’s ability to cause changes or to make something else move