Third Grade
Worksheets
What Is Air?
What is air? You can't see it. You can't smell it. But air is real. Without air, you would die. Why? Living things need air. Your dog or cat needs air. Plants need air, too. Even a worm needs air!
Air is a mix of different kinds of gases. The air we breathe is mostly a gas called nitrogen. We don't need nitrogen. Nitrogen doesn't hurt us, either. There is also a gas called oxygen in our air. Air has some other gases in it, too. Oxygen is the kind of gas that we need to live. Every tiny little part of your body, called a cell, needs air. When you breathe in air, it goes into your lungs. The oxygen in the air goes into your blood. Your blood takes the oxygen to every little cell in your body. Cells use oxygen to get the energy from the food you eat.
Air takes up space. You can see that when you blow up a balloon. With each breath, you can see the balloon get bigger and bigger.
