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Every day in every country in the world, the sun rises in the east and sets in the west. The sun is used to help define the day. It provides light for people to work by, it is responsible for photosynthesis that allows plants and crops to grow, it suffuses your bones with vitamin D, dries clothes, papads, red chillies, it dictates the weather systems and, most importantly, it provides energy.
Every day, energy arrives at the surface of the earth. In the middle of the day, at solar noon, the sun’s energy arrives at the earth’s surface with a peak value of 1 KW of energy per square metre. If this energy were harnessed it could provide all the electrical energy needs of every country in the world.
Energy arrives in the form of heat and light. The former is being used to warm houses, provide hot water, cook and process food, while the latter is converted into electrical energy with the help of photovoltaic technology.
In the 1830s, the British astronomer John Herschel used a solar collector box to cook food during an expedition to Africa. Since then, the many designs of solar cookers and their increased usage have played a huge role in stopping deforestation, reducing greenhouse gases, slowing down global warming, cutting cooking fuel costs and providing employment and healthy food to people.
You too can make your own solar oven.
What you need
- A large family-size recycled pizza box or flat-top cardboard box (the bigger the box, the more food you can cook).
- Black card paper.
- Aluminium foil (kitchen wrapping foil works too).
- Clear plastic (heavy plastic laminate works best).
- Non-toxic glue, tape, scissors, ruler, magic marker.
- A branch or straw (one foot long).
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How to make a solar oven |
| Step 1 |
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Draw a one-inch border on all four sides of the top of the pizza box. Cut along three sides, leaving the line along the back of the box uncut. |
| Step 2 |
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Form a flap by gently folding back along the uncut line to form a crease. Cut a piece of aluminium foil to fit on the inside of the flap. Smooth out any wrinkles and glue into place. Measure a piece of plastic to fit over the opening you created by forming the flap in the pizza box. The plastic should be cut larger than the opening so that it can be taped to the underside of the box top. Be sure the plastic becomes a tightly sealed window so that air cannot escape from inside the oven. |
| Step 3 |
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Cut another piece of aluminium foil to line the bottom of the pizza box, and carefully glue it into place. Cover the aluminium foil with a piece of black card paper and tape into place. |
| Step 4 |
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Close the pizza box top (window), prop open the flap with a short branch, straw, or other device, and face towards the sun. Adjust the box until the aluminium reflects the maximum sunlight through the window into the oven interior. |
Your solar oven is ready! |
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The pizza box solar oven can reach temperatures of up to 275 degrees. That’s hot enough to cook food and kill germs in water. A general rule for cooking in a solar oven is to get the food in early. And don’t worry about overcooking. Expect the cooking time to take about twice as long as conventional cooking methods, and allow about half-an-hour for pre-heating. You can try re-heating pizza, cooking small quantities of rice and dal in flat watis (bowls), or even baking cookies and biscuits.
Compiled from various sources by Shailendra Yashwant
InfoChange News & Features, March 2006
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