Oxygen is a kind of gas. Oxygen is found in the air, soil, and water. Nearly all living things need oxygen to stay alive. Image to left: An oxygen atom has eight electrons. There are two empty electron spaces in oxygen's outer shell. Credit: World Book illustration by Mark Swindle Ordinary oxygen makes up part of the atmosphere, or air, around the Earth. This oxygen has no color, taste, or smell.

Another form of oxygen, called ozone, is found in the atmosphere in small amounts. But ozone high up in the atmosphere is very important to life on Earth. This ozone layer protects the Earth from dangerous rays of the sun. Oxygen has many uses in industry. It is used to make steel and burn fuel. It is also sometimes used in explosives. How to cite this article: To cite this article, World Book recommends the following format: "Oxygen." The World Book Student Discovery Encyclopedia. Chicago: World Book, Inc., 2005.