The Atmosphere and Beyond Mr. Leslie’s Science Class

The Atmosphere Gases in the Air Nitrogen – Plants need this to grow. Oxygen – Living animals need this to breathe Carbon Dioxide – helps hold heat on Earth Oxygen

What are the two main gases? The two main gases in air are nitrogen and oxygen.

Earth’s Blanket Earth’s blanket is a layer of gases called the atmosphere. The sun heats the Earth, and the atmosphere holds the heat close to Earth’s surface. The weight of air as it presses down is called air pressure. Your body is used to air pressure, so you do not feel it.

Earth’s atmosphere There are four layers to our atmosphere. Thermosphere Mesosphere Stratosphere Troposphere- (closest to Earth) Thermosphere

Troposphere (closest to Earth) Earth’s weather occurs in the troposphere. Weather is the conditions of the atmosphere at a certain place and time.

Stratosphere (6 to 30 miles above Earth) This layer protects a lot of the harmful Sun’s rays from reaching Earth. Some jet planes fly in the stratosphere. There is no weather in this layer so the plane ride is nice and smooth.

Mesosphere (30 to 50 miles above Earth) Most meteors burn up when they reach this layer. (shooting stars) The coldest temperatures in the atmosphere are found here.

Thermosphere (50 to 430 miles above Earth) Space begins at the top of this layer. Many space shuttles actually travel in Earth’s atmosphere and never reach space.

Greenhouse Effect Heat from the Sun passes through the atmosphere and is reflected from the surface of the Earth. Gases in the atmosphere trap some of this heat and keep it close to Earth’s surface.