1. Atmospheric Pressure Science 10

2. Why Does Atmospheric Pressure Exist?  Because the air in the atmosphere is pulled toward the Earth by Gravity  Currently there is a column of air above you that extends approximately 180km up with a mass of about 10000kg

3. Why Doesn’t Atmospheric Pressure Only Push Down on Us?  Because a gas is free to move (fills space), while it is held to Earth by gravity, it also is free to move around objects and we can move through it  Therefore, when we raise our hand, we don’t have to lift 10000kg of air in order to do so

4. Air Pressure Decreases with Altitude  The further from the surface of the Earth, the less air that is above you so the air pressure is lower.  Plot the Altitude versus Pressure data in the following table Altitude (km) Pressure (kPa) 0101.3 188.5 277.3 367.6 459.0 551.6 7.536.8 1026.2 1513.3 206.8 253.5 50.1

6. Atmospheric Composition  Nitrogen – 78%  Oxygen – 21%  Other – 1% Argon Carbon dioxide Neon Helium Methane Krypton Xenon Hydrogen Ozone

7. Chapter 13 Review  Complete Questions 1-15 and 21-26 on page 450-1