Date: Thursday, June 5th. 2014 Topic: Layers of the Atmosphere

The Atmosphere Layers are five: The first is: Troposphere The second is: Stratosphere The third is: Mesosphere The fourth is: Thermosphere The fifth is: Exosphere

Troposphere It’s the lowest layer of the atmosphere, it begins at the surface and extends 7km (23,000 feet) at the poles, and 17km (60,000) at the equator with some variation due to weather factors. It is the most dense. Known as the weather layer, snow, wind and rain are found in this layer. As you climb higher, the temperature drops from about 17 to -62 degrees Celsius.

Stratosphere Starts just above the troposphere and extends to 50km (31 miles higher). It is dry and less dense. The temperature of this region increases to -3 degrees Celsius due to the absorption of ultraviolet radiation. The ozone layer which absorbs and scatters the ultraviolet radiation is in this layer. 99 percent of air is located in the troposphere and stratosphere.

Mesosphere Starts just above the stratosphere and extends to 85km which 553 miles higher. In this region the temperatures again fall as low as -93 degrees Celsius as you increase in altitude. The chemicals are in an excited state as they absorb energy from the Sun. This is where most meteors burn up when they reach the atmosphere.

Thermosphere Starts just above the mesosphere and extends 600km (372 miles high). The temperatures go up as you increase in altitude due to the Sun’s energy. Temperatures can go as high as 1,727 degrees Celsius. Chemical reactions happen much faster here than on the surface of the Earth because of the high temperatures. This layer is known as the upper atmosphere. The thermosphere also includes the Ionisphere, a region which is filled with charged particles.

Exosphere Starts 500km (311 miles) above the Earth, it is the highest layer. It starts at the top to the thermosphere and continues until it merges with the interplanetary gases or space. In this region of the atmosphere hydrogen and helium are the prime components and are only present at extremely low densities.

LAYERS OF THE ATMOSPHERE Exercises in class LAYERS OF THE ATMOSPHERE Name of the layer: It extends to: Characteristics Troposphere 7 km at the poles and 17 km at the equator. The weather layer. Stratosphere 50 km The ozone layer is here. Mesosphere. 80 km The meteors burn up. Thermosphere. 320 km Includes de Ionesphere. Exosphere Starts at 500 km. Hydrogen and Helium.