Earth has 5 layers of atmosphere, troposphere, stratosphere, mesosphere, thermosphere and the exosphere.
The higher altitude you go the thinner the air gets.
Troposphere is known as the weather layer because weather occur on this layer.
Stratosphere is where the air begins to get cold. The higher altitude you go the colder the air gets. Ozone layer is on the stratosphere. Ozone is a gas that protects us from too much solar radiation.
Mesosphere is the layer where meteors disintegrate from friction.
Thermosphere is the hottest layer of the atmosphere. Charged particles form on the thermosphere called ionosphere.
Exosphere is the thinnest atmosphere there is. The sky is blue because the gases in the exosphere scatter. Light has different wavelength and each wavelength has a color. Blue is the color that gets through the exosphere so thats why the sky is blue.