1.
Energy and Energy Resources<br />To day we are going to learn about ;<br />Thermal radiation and surface radiation<br />

2.
Starter Activity<br />What is Energy?Identify the forms of energy from the photographs.<br />

3.
What is another name for heat energy?<br />

4.
Energy and Forms of Energy<br />Energy is ability to do work.<br />The unit of energy is Joule(J)<br />Forms of energy; <br />Light energy, Heat energy, Electrical energy, Sound energy, Kinetic energy, Potential energy (Gravitational or Elastic) and Chemical energy.<br />

5.
Lesson Objectives<br />By the end of the lesson pupils should know that;<br />objects give off thermal radiations depending on the temperature of an object.<br />surfaces emit and absorb radiations.<br />

6.
The Key Words<br />Thermal Radiation, Conduction, Convection, Green house effect, Electromagnetic spectrum, Wave length, Gammer rays, infrared, ultraviolet rays, visible light, X-ray, radio wave, <br />

7.
Activity 2<br />In pairs;<br /> Discuss how heat energies is transferred in A, B and C in the above diagram <br />

8.
Activity 3<br />In groups of three;<br /> Discuss why the body of the above animals are showing different colours .<br />

9.
Thermal Radiation <br />Every objects gives out (emits) different amounts of thermal radiation depending on their temperature and their surface .<br />The hotter an object, the more thermal radiation it emits (e.g Sun ).<br />The red part on the animals indicate that area has more heat ( the region is richly supplied with blood).<br />The blue parts of the animal indicate that the area is cold (has less heat)<br />

10.
Activity 4(4 minutes Task)<br />Turn to page 229 and read Energy from the Sun.<br />Using information from the page above, discuss the following in pairs;<br />1. How does heat energy from the sun reach us on earth?<br />2. What happens to most of the radiations in the Earth’s atmosphere?<br />

11.
Heat Energy from the Sun<br />The sun emits radiation in form electromagnetic waves.<br />Earth’s atmosphere blocks most of the radiation, such as ultraviolet rays.<br />But it doesn’t block thermal radiation.<br />

12.
Green House Effect <br />What is green house effect?<br />

13.
The warming of the Earth by its atmosphere is called the greenhouse effect.Without its atmosphere, the Earth temperature would be -18 degree Celsius.<br />

14.
Green house effect.<br />The Earth’s atmosphere acts like a greenhouse made of glass.<br />In a green house , shorter wavelengths radiation from the sun can pass through the glass.<br />Longer wavelength thermal radiation is trapped inside by the glass, making the greenhouse warm.<br />

15.
Activity 5Question and Answer<br />1. What are the green house gases ?<br />2. And how do they cause green house effect?<br />

16.
Examples of Greenhouse gases<br />1. Carbon dioxide<br />2. Methane<br />3. Water vapour<br />These gases absorbs the Earth’s infrared radiation<br />

17.
Surfaces and Radiation<br />Look at the pictures below and in pairs;<br />Discussed why the thermal blanket and fire suit have shiny outer surface and the car radiator is painted black?<br />Thermal Blanket<br />Fire Man<br />Car Radiator<br />

18.
Surfaces and Radiation<br />Dull black surface loses energy more quickly; its a good radiator and good absorber. It takes in and give out a lot of radiation. That’s why car radiators and motor bike engine are painted black in colour.<br />The shiny surfaces reduces radiation (and convection and evaporation). It is a poor radiator and poor absorber. That’s why the thermal blankets and fire suit have shiny outer surfaces.<br />

19.
Plenary<br />