23 4. The glucose from food is “burnt” in our body in order to release energy. This occurs through a process known as oxidation. The oxygen that we take in from fresh air helps in oxidizing glucose. Oxidation of glucose in our body does not release light and heat energy. Instead, the energy released is stored as chemical energy in special molecules known as ATP molecules. ATP can be called the energy currency of our body.
KEY MESSAGES
Sugar and glucose when burned release energy in the form of light and heat. Our body breaks down carbohydrates from food into glucose. Glucose in our body is oxidized with the help of oxygen in air to release chemical energy.
LEARNING CHECK How do oxygen and glucose in our body give us energy? (Ans: Glucose is burnt in our body using oxygen to release energy for our use)
TRY IT YOURSELF Although candles are so common to us, there is a lot of science behind the light of a candle flame. Light a candle at home and carefully observe how it burns. Which part of the wax melts first? When does the flame produce soot? What are the different colors in a candle flame? You can learn a lot by observing candles. Take some raw grains of wheat and chew it for a long time without swallowing. Does it taste sweet? The next time your mother makes jalebis or gulabjamun, see how she makes the sugar syrup for the sweet.
INTERESTING INFORMATION People often wrongly believe that when a burning candle is placed under a container, it uses up all the oxygen in it. There is still a lot of oxygen left under the container, just not enough for the candle to burn.
WEB RESOURCES http://www.youtube.com/watch?v=pRiXsQLYoJA http://misconceptions.science-book.net/wp-content/uploads/2011/09/Chap2-1.pdf
REFERENCES Figure 7: http://upload.wikimedia.org/wikipedia/commons/f/fa/Candle-flame-and-reflection.jpg Figure 8: http://www.mcutter.com/nat/experiment626/11rawsugar.jpg
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