Patricia Jane Elwell, aged 12, of Westbrook, Maine for her question:

Where does the warmth of our bodies come from?

The food we eat is fuel to keep the body going. Mostly we forget after about a meal/we have eaten it. But this is when the wonderful body takes over and uses the food to rebuild and give us energy, It does this by a sort of slow burning. This burning does not blaze away like a fire in a grate. But the two fires are alike in many ways, Both need fuel and oxygen, Both give off heat as they burn. Both leave ashes and waste stuff to be disposed of.

Cold blooded creatures, such as toads, lose their body heat as fast as they make it. They stay only a little warmer than the air around them. Though we call a toad a cold blooded animal, on a hot day his temperature is actually a little higher than yours, He has no way of regulating his body temperature to keep himself warmer or cooler than the air around  him.

Human beings and warm blooded animals have a more economical way of handling their body heat. The major job is to keep warmer than the air around. One way is to muffle up. Warm blooded animals wear either fur coats or feathers. These coats trap small pockets of warm air as it escapes from the skin. Human beings wear clothes to hold in body warmth..

All burning processes increase with more oxygen. This is true of the slow burning of the body1s fuel. Our lungs are far more complex than the lungs of a toad. They can take in bigger breaths, more air and more oxygen, a1.1 warm blooded creatures have this large lung capacity.

Body warmth, then, is created by the slow burning of fuel. Oxygen combines with certain hydrocarbons in our food. Heat and energy are released in the process. Why then doesn’t the body burn up and roast after a heavy meal. There are certain checks and balances which keep the body temperature steady and even.

The body uses only the fuel it needs to keep going. Surplus food is stored as fat, surplus fat is broken down and used as fuel when needed. If you were starved for a few days, the' body would draw upon its stored fuel.

There are checks to cool off the body in hot weather. The skin is full of sweat glands which obey signals from the nervous system. In hot weather, the nerves in the skin send messages to the cooling system in the brain stem. Orders go out for the sweat glands to cover the skin with a film of moisture. As the moisture evaporates it cools the air above the skin. This cools the skin which in turn cools the tiny blood vessels near the surface.

Another temperature control operates in cold weather. Exercise is one way of burning up body fuel and creating heat. If you refuse to run up and down, your wonderful body will try to help you out. It forces your muscles to relax and contract without your permission. Pretty soon you are shivering and shaking. This is exercise which uses up body fuel and creates body warmth