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1. Objective2. Materials used3. Design and construction skills4. Application of physics principle in the design5. Test of the cooker6. Conclusion and discussion7. Group members list8. Cost

1.Objective We make this solar cooker in order to apply our knowledge about Physics. We want to apply the Physics principles we have learnt. We also want to know whether the theories are true or not. We hope the water can be heated up to 70°C and the heater

can work efficiently.

2. Materials used

a) black plastic bagsb) aluminum foil c) paper boxesd) plastic filme) rope

3. Design and construction skills The paper box is wrapped by a layer of black plastic bag. Inside it, we cove it with aluminium foil. We also made a cover for the cooker. It is wrapped by plastic bag and aluminium foil and there is a transparent plastic sheet in the middle of the cover, which allows sunlight to come in easily and the sunlight will be difficult to escape away. We added two thick papers wrapped with aluminium foil to reflect the sunlight onto the can inside the cooker.

4. Application of physics principle in the design We use black plastic bag to cover the box because black surface is a good absorber of radiation. The box can be heated more quickly. We covered the interior with silvery aluminium foil because silvery surface is a poor absorber of radiation. It prevents heat from losing to the surroundings easily and reflects the light away. The cover of the cooker is transparent because sunlight can enter into the cooker easily and is difficult to come out. Heat will be trapped inside the cooker and heat up the water in the can. It is due to the greenhouse effect. We use an insulating material to make the box to avoid heat lost to the

surroundings easily.

5. Test of the cooker

Date: 10/12/03Time (s) 0 5 10 15 20 25 30 35 40

Temperature (°C)

21 24.5 27.5 33 34 37 38 40 43

Date: 10/12/03

Time (s) 0 5 10 15 20

Temperature (°C)

22 26 31 33 35

6. Conclusion and discussion

To conclude, the reflection of light is very important. It can affect the experimental results. The sunlight should focus on the aluminium can so as to heat up the water. The aluminium foil should be folded smoothly so that the light will converge to focus. The use of radiation absorption and greenhouse effect is very significant.

7. Group members list

Ho Wing Yin 4C (3)Ting Ching Yee 4C (11) Wong Mei Yi 4C (13)

Yeung Hoi Ying 4C (16)

8. Cost

Aluminium foils $10Black plastic bags $2Transparent plastic sheet $5