Lenny Arlington, age 12, of Billings, Mont., for his question:

HOW IS ETHYLENE MADE?

Ethylene is an organic gas and it is one of the most important chemicals in the United States. Each year the chemical industry uses about 6 billion pounds of ethylene.

Ethylene is made by heating ethane and propane at high temperatures in the presence of catalysts. Ethylene is also a by product of petroleum refinery processes.

Ethylene is a colorless, flammable gas that has a faint, sweet odor. It is slightly lighter than air.

The chemical industry uses ethylene to prepare compounds such as ethylene oxide, polyethylene, ethyl alcohol, ethylbenzene, ethyl chloride and ethylene dichloride. Ethylene oxide is used to make ethylene glycol, which is an antifreeze.

The plastics industry uses polyethylene and converts ethylene to styrene, which is used for plastics and synthetic rubber.

Ethylene is also used to help ripen fruit.