AIR ALL AROUND US

Stretch your arms out in front of you without touching anything. Can you do it? You may not have touched an object, but your hands moved through the air, pushing it aside as they traveled. Air is the substance around us. It has weight, takes up space, and even moves around us as wind.

The air is all around you.

The Atmosphere

Like light and heat from the sun, our air is a crucial ingredient to maintaining life on our planet. The combination of gases present in our air, like oxygen, carbon dioxide, and water vapor, surround the Earth in a large belt called the atmosphere.

Earth's atmaosphere is made of many layers. Most of the weather changes we experience are happening at the lower level of our atmosphere, called the troposphere.

In the troposphere, we look up and see the clouds. We feel the rain when it falls to the Earth and we sense air moving around us as wind.

Earth's atmosphere.

Our atmosphere allows sunlight to pass through and reach the ground, bringing us the light and heat we need in order to survive. Once that heat is in our atmosphere, it is trapped. That trapped heat allows the Earth to maintain temperatures suited for living things. Without our atmosphere, life on Earth would not be possible.

Without the atmosphere there would be no flowers.

Have you enjoyed the pleasure of a cool breeze on a hot day, or held tight to the string of a kite as it dipped and danced in the air above you? What causes the air to move in our atmosphere?

The wind will carry this kite.

A hurricane viewed from a satellite.

Once again, the sun plays a role in creating weather conditions. We know that wind is moving air. When the sun heats the air, it actually stirs up the movement of the air.

Wind occurs when cool air advances on warm air, or when warm air pushes against cool air. Cool air is heavier than warm air, so when the two meet, the cool air pushes itself beneath the thinner, warmer air. The warm air moves up out of the way, and the cool air slides down to replace it. This movement produces wind.

There are other factors in creating wind as well, like the Earth's rotation and orbit, the interactions of temperature and water, and the different surface features of the Earth.

Cool air pushes the warmer air up and out of th way, creating wind.