In 1976 a scientist at Gonoshasto Kendra thought about this problem. “How can people boil water cheaply” he asked himself. It was a very hot day. He looked at the sun and suddenly remembered two important things. First will become very hot. Then the sun’s rays can shine through water. Now he will use the sun’s ray’s to boil water. He went to the market to buy some necessary things for his experiment. First, he bought a round bamboo basket. It was about four feet across. And bought three sticks. He also bought about a hundred pieces of mirror. The scientist carefully stuck the pieces of broken mirror to the inside of basket by using strong gum. At last, the inside of the basket was completely covered with about a hundred small pieces of mirror. Then the scientist took the basket outside, the sun shone brightly inside it. He stuck the three sticks into three holes in the basket. He put a large pot on top of the sticks. Then he poured water into the pot. The sun shone brightly in the basket under the pot. After 3 minutes he heard a very small noise from the pot. He looked in and saw the water was boiling. It’s called solar cooker.

The energy which we obtain from the sun rays is called solar energy. At present, mankind faces energy crisis. The era of wood and bio-mass has almost come to an end. The age of oil and natural gas would soon be over within the next few decades. Massive burning of world’s coal reserves may lead to a worldwide ecological disaster because coal burning emits the highest amount of carbon in the atmosphere. So, the only solution that mankind can look to is the massive use of solar energy in future because it has some advantages over other forms of renewable energies. The world’s petroleum consumption has increased from annually 3 billion barrels today. In the next 25 years, the world’s population is expected to be about 8 billion which is 30 percent higher than today. Developing countries will grow their economics about two times faster than industrialised countries. Global economic growth is expected to continue at 3 percent per year. Consequently, the global demand for energy will grow at about 1.7 percent per years on an averages. It indicates a 50 percent rise of energy consumption by 2030. If the world’s daily petroleum consumption in 220 million barrels, it will rise to 335 million barrels by that time. And hence, leading industrial countries have taken initiatives to tap alternative energy sources. We should make careful research of the impact and massive use of solar energy in future.