Oxygen

Oxygen is a very important gas. It is in the air all around us. People, animals, and even fish need oxygen to live. You cannot see, smell, or taste it. About one-fifth of the air we breathe is oxygen.

Breathing Oxygen

Every time you take a breath, oxygen goes into your lungs. From there it travels into your blood. Your blood carries the oxygen to every part of your body. Your cells use oxygen to turn food into energy. Without oxygen, people can only live for a few minutes.

Where It Comes From

Plants and tiny ocean creatures called phytoplankton make oxygen. They take in a gas called carbon dioxide and use sunlight to make food. As they do, they release oxygen into the air and water. This is why forests and oceans are so important. They keep the air full of the oxygen we need.

Fun Facts

• Oxygen makes up about 21 percent of Earth's air.
• Fire needs oxygen to burn, which is why blowing on flames can make them bigger.
• The letter for oxygen on the periodic table is O.

Did You Know?

Liquid oxygen is a pale blue color and it is so cold that it can freeze almost anything it touches.