Air is all around us. It is around us as we walk and play. From the time we were born air is around us on every side. When we sit down, it is around us. When we go to bed, air is also around us. We live in air. We can live without food or water for a few days, but we cannot live for more than a few minutes without air. We take in air. When we are working or running we need more air. When we are asleep, we need less air. We live in air, but we cannot see it. We can only feel it when it is moving. Moving air is called wind. How can we make air move? Here is one way. Hold an open book in front of your face, close it quickly. What can you feel? What you feel is air.