# Composition of Air - air is made up of approximately $78\%$ Nitrogen, $21\%$ Oxygen, and $1\%$ trace gasses ![[composition of air.png]] # Layers of the Atmosphere - almost all weather occurs in the troposphere, which extends from the surface to approximately 7 miles above the earth - the troposphere extends higher during hotter times of the year ![[atmosphere layers.png]] # ![[Standard Atmospheric Conditions]]