Atmospheric Pressure

• What is the atmosphere?

  A relatively thin layer of air around the Earth
• Describe what happens to the atmosphere and atmospheric pressure at a greater altitude?

  The greater the altitude, the less dense the atmosphere and the lower the atmospheric pressure
• What happens at a high altitude?

  There is less air above a surface than at lower altitudes , so there is a smaller weight of air acting on the surface
• What causes the pressure of the atmosphere?

  Molecules colliding with the surface