Conduct online research regarding the different layers of the atmosphere. Write a short description of your findings. In your description, mention the different layers that exist and their properties of altitude, gravity, and air pressure.
Answers
⚪⭐The atmosphere, which is the envelope of gases that surround our planet, extends from the ground into space over several hundred kilometers. It is not uniformly thick or dense throughout. The atmosphere is densest near the ground and becomes thinner as we move farther away from the planet. Air pressure also decreases as we move farther away from the surface. There are five distinct layers in the atmosphere, based on temperature changes.⭐
⚪⭐The troposphere is the layer closest to the ground. It extends to a height of 12 kilometers above the surface. Earth's surface absorbs radiation from the Sun and heats up. The ground radiates this heat back into the atmosphere. The troposphere gets its heat from the re-radiated heat of the ground. Therefore, the temperature in the troposphere is highest near the ground and decreases as we move higher. Air moves vertically in the troposphere, rising and falling as it is heated and cooled. All weather phenomena take place in the troposphere. The tropopause is the upper layer of the troposphere, and it separates the troposphere from the next layer of the atmosphere.⭐
⚪⭐The stratosphere is the next layer. It extends above the troposphere to a height of 50 kilometers from Earth's surface, or the lithosphere. The top of the stratosphere is rich in ozone gas (O3), which forms the ozone layer. The temperature increases here because molecular ozone absorbs ultraviolet radiation and heats up. Because the concentration of ozone is highest at the top of the stratosphere, there is greater absorption of ultraviolet radiation there. Consequently, the temperature is highest at the top layers of the stratosphere and decreases with altitude as the concentration of ozone decreases. There is very little air turbulence in the stratosphere, because the temperature profile of increasing heat with height does not cause air to move vertically. All air movement here is mostly horizontal. The ozone layer acts as a shield for Earth, because it absorbs ultraviolet radiation from the Sun. The stratopause is the layer that separates the stratosphere from the mesosphere, where the temperature stops increasing with altitude.⭐
⚪⭐The third layer of the atmosphere is the mesosphere. It extends from the stratopause to a height of about 85 kilometers from Earth's lithosphere. The mesosphere does not absorb any radiation, and thus the temperature decreases with increasing altitude. It is the coldest region of the atmosphere and temperatures are as low as -90° Celsius at the top of this layer.⭐
⚪⭐The thermosphere lies above the mesopause, which separates the mesosphere from the thermosphere, to a height of 500 to 1,000 kilometers from the Earth's surface. Its height varies because of changes in solar activity, and its temperature increases with height. It is the hottest part of the atmosphere, and temperatures here can reach as high as 1,500° Celsius. The air is extremely rarified. In the lower part of the thermosphere, to a height of about 500 kilometers, lies the ionosphere. In the ionosphere, gas molecules absorb both ultraviolet and x-ray radiation from the Sun and become electrically charged ions. Radio waves bounce off the ions in this layer and are reflected back to Earth.⭐
⚪⭐The exosphere is the fifth layer of the atmosphere, and it lies above the thermosphere. It extends out from the thermopause (also called the exobase), which separates the thermosphere from the exosphere. The air is extremely rarified in this layer, with gas molecules escaping into space.⭐