Solar cooker

1)How can we make use of reflection to gather more solar

energy ? We use black boxes to absorb heat ene

rgy and aluminium paper to reflect solar energy onto a tin of water.

2)What kind of materials should be used to construct the body of

the solar cooker?Why?• Black box – Absorb more solar energy

• Aluminium paper – Reflect solar energy

• Glue – to stick the aluminium paper

• Tin – container of water

3)what other measure can help to reduce heat loss by conduction

and convection? A polystyrene box reduce heat loss by conduction . It is an insulating box . A lid reduce heat loss by convection . Warm air can’t easily move upward to escape away fr

om the box.

4)How can we make use of greenhouse effect to trap more

solar energy?To trap heat energy making use of greenhouse

effect . The radiation enters the box and warms up the air inside. This radiation can’t easily escape through the glass and is trapped inside the box . This keeps the boxe warm , so that the temperature of water will increase gradually under the sun .

5)How should the container of water look like?

A aluminium can paint in black colour . It is because black colour surface is a good absorber of heat . Then , we can wrap the can with some cotton. It is because cotton can trap heat . Water is filled to ¾ of the can. So the water can heat up more quickly .

6) When and how the solar cooker should be used to enhance

its performance? After 10 minutes , the sun made the air of

solar cooker warm up . So the temperature of the water started increasing . At the end , the temperature of solar cooker increase 18 degrees .

Data recording

Time/min 0 5 10 15 20 25 30

Temperature/oC 20 21 23 24 26 26.5 28

Time/min 35 40 45 50 55 60 65

Temperature/oC 29 30 32 33 35 36 38

COMMENT

We think this project is difficult . It is because we need so many material to make the solar cooker . Unfortunately , we have to make the solar cooker once again , because our solar cooker had been thrown away by somebody . Then , we have to do a lot of experiment , and we should discuss the result .

• Group members :• 4D (1, 8, 9, 16, 19)

The end