A simple, portable Cooker for Heating the water By using Sunlight

1. Solar Cooker A simple, portable Cooker for Heating the water By using Sunlight

2. Experiment for transferring of heat • In this experiment , energy resources are limited . Solar energy is one of them . We use solar energy to heat up a can of water. By using the solar cooker designed by our group, we try to investigate how to make a perfect solar cooker to heat up the water more efficiently.

3. Our design : solar cooker Our solar cooker looks like a box.We will put a can of water inside the box . However , we will not close the lid as it will block the sunlight to go through.Also , we paste some aluminium foil onto the inner surface of the box so as to reflect sunlight onto the can of the water .

4. Material used * Use a box . Use a glass cover putting on top so as to trap energy inside the box, which make use of the greenhouse effect to trap the energy inside. Use the aluminium foil Use black adhesive paper(we stick it on the surface of the box that use for absorbing the sunlight more easily )

5. The picture of the solar cooker • We are doing pretty well with reducing the materials needed to solar cook. I used glass cover and it seemed to hold up under the heat for several cooking times. the air was warmer inside the glass . So the temperature of the water will increase . And also , the surface of can is black in colour .

6. The theory we used in cooker • Firstly , we use aluminium foil to cover the surface inside the box is to reflect the sunlight to the opposite side , as the silver surface is a good reflector of light and poor absorber of heat . So the light (energy) will be reflected to the middle of box . • Then , We colour the surface of the can from silvery to black . As black surface is a good absorber of heat , so it can help to absorb the sunlight much better .

7. After that , We use a glass cover to cover the can of water . We want to make a condition as the greenhouse . The glass allow radiation from Sun to pass through , the radiation entering to glass warms up the air that inside the glass cover . The warm air emit infra-red radiation , but the radiation can’t escape through the glass easily and is trapped inside , so the temperature inside the glass will be higher to use for heating up the water .

8. The result • Finally , our solar cooker heats up the water from 27.0 – 47.0 degrees celsius . Although the water hasn’t reached the boiling point , the water is hot enough to hurt our body . We think this experiment is quite successful because we can use what we have learnt in the book and use on the daily life . Also , we can use our own solar cooker to try to heat up something . It help us understand the heat theory more clearly .

9. The error on this experiment • First , the aluminium foil will reflect the light to many directions , so it will reduce the energy pass through the can . • As the glass cover of our solar cooker is too small and don’t have enough spaces to put a thermometer inside , so when after 5 minutes , we need to open the cover and measure the temperature , it makes a large of energy lost to the surrounding air . • Also , the sunlight supply is a important problem on that day , the sunlight isn’t shiny so we can’t do the experiment more successful .

10. Our comment • We have learnt many things during this experiment . We use the theory of transferring heat such as radiation , conduction , the different between shiny object and dull object and greenhouse effect . This activity help us to remember them . Moreover , it let us know that physics can be used on our daily life and increase the curiosity of us in physics . • We are looking forward to other interesting experiment .

11. Our group • Leader : ( 25 ) • Group member : • (27) • (28) • (35) • (40) • THE END