4E(2004-2005)Chan man Hang(2)Chow Chui Shan(5)Lam Yuen Ching(10)Ma King Man(13)Yeung Po Yee(16)

Magnifying glass

mirror

wool

mirror

wrap

Inner Silverysurface

Aluminium Foil

Can ( Black Surface)

- Aluminium Can

- Aluminium Foil

- Cardboard

- Knitting Wool

- Cling Wrap

- Mirror

- Magnifying glass

- Black Paper

- Wire

-the inner surface of the solar cooker is covered by aluminium foil to reflect and focus the sunlight onto the can of water

-using lots of mirrors to reflect and focus the sunlight onto the can of water

-the can is painted black in color dull black surface is  a good absorber of heat

-Using wools to cover the outer part of the solar cooker Wools are poor conductor of heat and thus can prevent loss of heat by conduction

-Using wrap to cover the upper part of the solar cooker   trap the heat inside the solar cooker

-Using magnifying glasses to focus the sunlight onto the can of water   the sunlight will be more concentrated so as to heat up the can of water more easily

-When the weather is cloudy, we use our woolen jacket to surround the solar cooker. to prevent the heat loss by conduction- When the weather is fine, we use a lot of mirrors to focus the sunlight onto the water.

Time(min) 0 5 10 15 20 25 30 35 40 45 50 55 60

Temp(℃) 29 30 31 32 34 35 36 37 38 39

Variation of the temperature of water in the solar cooker

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5

10

15

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30

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45

0 5 10 15 20 25 30 35 40 45

Temp.

Tem

perature(C)

Time(min)

Time(min) 0 5 10 15 20 25 30 35 40 45 50 55 60

Temp(℃) 27 31 34 36 40 43 47 50 52 55 57 60 63

Variation of the temperature of water in the solar cooker

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10

20

30

40

50

60

70

0 5 10 15 20 25 30 35 40 45 50 55 60

Temp©

Tem

perature

©

The water can be heated up when it is put in a solar cooker under sunlight.

The physics principles applied in solar cooker is – Radiation, Conduction, Reflection and Greenhouse Effect.