1. Transfer of Heat Continued

2. Last class we learned about two ways in which heat is transferred. These are Last class we learned about two ways in which heat is transferred. These are Conduction Conduction Convection Convection

3. The third way in which heat is transferred is by radiation Both conduction and convection require the movement of particles to transfer heat. Both conduction and convection require the movement of particles to transfer heat. Radiation does not involve particles. It is the transfer of energy through invisible waves given off by an energy source. Radiation does not involve particles. It is the transfer of energy through invisible waves given off by an energy source.

4. The heat from the sun is an example of radiation. This heat is transferred by invisible infrared waves. The heat from the sun is an example of radiation. This heat is transferred by invisible infrared waves. All hot solids (including you!), liquids and gases radiate invisible heat waves. Infrared cameras are able to form images of this heat. All hot solids (including you!), liquids and gases radiate invisible heat waves. Infrared cameras are able to form images of this heat.

5. Uses of infrared imaging: Satellites can detect infrared waves given off by objects on earth. This can be used to track pollution and weather. Satellites can detect infrared waves given off by objects on earth. This can be used to track pollution and weather.

6. Infrared images can be used in healthcare Infrared images can be used in healthcare And can be used to monitor the health of the environment. And can be used to monitor the health of the environment.

7. How radiant energy warms up objects: When invisible waves of radiant energy come in contact with a solid, the particles in the solid gain energy and vibrate more quickly. The solid heats up. When invisible waves of radiant energy come in contact with a solid, the particles in the solid gain energy and vibrate more quickly. The solid heats up. The solid also reradiates some of the energy back into the surrounding area. The solid also reradiates some of the energy back into the surrounding area.

8. Coloured solids absorb radiant energy, but clear solids, liquids and gases just allow it to pass through. Coloured solids absorb radiant energy, but clear solids, liquids and gases just allow it to pass through. That’s why the seats of your car can get very hot on a summer day, while the windows themselves remain cool to touch.

9. Add the following words to your glossary, and write the definition for each: Radiation Radiation Infrared wave Infrared wave

10. Homework: Write the following questions in your notebook and answer them: In what state of matter can conduction occur? In what state of matter can conduction occur? Can convection occur in both liquids and gases? Suggest a reason for your answer using particle theory. Can convection occur in both liquids and gases? Suggest a reason for your answer using particle theory. List two things that happen when radiant energy waves contact a solid. List two things that happen when radiant energy waves contact a solid.