Andy Kerr, age 7, of Washington, I11., for his question:
WHY DO THINGS DECOMPOSE?
Decomposition is a process in which a substance is broken down into other types of substances. A substance which can be decomposed into two or more other materials is called a compound. And the parts that make up compounds are called elements. An element a single substance cannot be broken down into other substances by chemical reactions.
There is a natural decomposition in life. Nature has a cycle in which organic matter is eventually broken down from complex compounds into simple elements.
When a leaf falls from a tree, or when a plant oanimal dies, other natural materials lying in the soil will gradually decay or decompose the dead creature or plant. The chemical changes of decomposition are usually started by bacteria that is always present in living things and in the soil.
In decomposition, the materials gradually are decayed to simpler organic acids, to salts, to carbon dioxide and to water all of which can be used by living plants to be recombined and built up into the new substances used in living plants and animals.
The process actually forms the life cycle. Decomposed leaves enrich the soil, and the richness goes back to the next generation of plants.
Another way decomposition can take place is by heating. Baking soda, for example, can be heated in a container until the new substance of water is formed from it.
To decompose water into its elements, hydrogen and oxygen, water would have to be heated to a very high temperature. An easier way to break up water would be by a process called electrolysis. With this method, an electric current is passed through the water and decomposition of the water would result.
A carbon cycle is nature's way of adjusting the amounts of carbon'and oxygen, so that both elements will remain in proper balance. Green plants need carbon dioxide in order to make food, but they release oxygen as their waste product. When men or animals consume food fuel, carbon dioxide is exhaled and excreted. Decay of both plant and animal life after death produces carbon dioxide the material needed for green plants to start the cycle again.
Plants utilize carbon dioxide from the air and water absorbed by their roots. With the sun's energy and the green pigment chlorophyll, a chemical reaction results to form a carbohydrate, out of which the plant builds its own body. The waste product, oxygen, is released and the balance remains intact: