ATMOSPHERIC LAYERS

 Earth’s atmosphere is made up of several layers of gases in different mixtures that surround our planet. The atmosphere puts pressure on the planet. The amount of pressure becomes less and less the further away from Earth’s surface you are. Most of the time when we think of the atmosphere, we think of the part that is closest to us. At any specific moment in time, the overall condition of Earth’s atmosphere, including the part we can see, and the parts we cannot, is called weather. You have enough experience with weather to know that it can change, and it frequently does. That is because the conditions of the atmosphere can change. The amount of the different kinds of gases that can be found above any certain place on Earth varies. The most common gases in our atmosphere are nitrogen, oxygen, and carbon dioxide.

There are four main layers in Earth’s atmosphere: the troposphere, the stratosphere, the mesosphere, and the thermosphere. The layer that is closest to the surface of Earth is called the troposphere. It extends up from the surface of Earth for about 11 kilometers. We experience almost all weather in this layer, and airplanes fly here. About three fourths of our atmosphere’s air is also found here. Just above the troposphere is the stratosphere. It extends to about 50 kilometers above Earth’s surface. Most of our planets ozone layer is in this colder, drier layer. Ozone is important to the health of our planet because it helps keep some of the Sun’s dangerous radiation from reaching the planet’s surface. If we continue upward, the next layer is the mesosphere. It extends up to about 80 kilometers above Earth’s surface. The mesosphere is extremely cold. It is within this layer that you are most likely to find meteors, most of which will completely burn up before they ever reach Earth’s surface. The final layer is the thermosphere, the layer that is closest to the Sun. Temperatures in the thermosphere can be over 1,500º Celsius! Together, the layers of our atmosphere protect Earth and provide the conditions needed to support life.

Name:__________________________________

Answer the following questions based on the reading passage. Don’t forget to go back to the passage whenever necessary to find or confirm your answers.

1)   Why do you suppose that weather happens in the troposphere?

2)   If you were to send a bottle rocket 15 kilometers up into the air, which layer of the atmosphere would it be in?

3)   Which layer has the second warmest temperatures? How do you know?

4)   Why is it important to protect the stratosphere?

5)   Why aren’t there many meteors in the troposphere?