Contents
Key Stage 3
Meaning
Atmospheric Pressure is the pressure on an object due to the particles of gas in the atmosphere colliding with the object.
About Atmospheric Pressure
- Atmospheric Pressure changes with height above the Earths surface. The higher up, the lower the pressure.
- The atmospheric pressure at sea level is 101,000Pa.
- The force responsible for atmospheric pressure is the weight of all the particles above the object.
Variation with Height
- As the height of an object increases the atmospheric pressure decreases.
- Pressure in a fluid is due to the weight of the fluid above the object. As an object gets higher, there is less atmosphere above that object.
- The reduction in pressure is related to the density and motion of particles in the atmosphere.
At higher altitudes:
- The atmosphere is less dense - Less frequent collisions between the particles and the surface of the object.
- The temperature is colder - Particles move more slowly leading to less collisions and the collisions which do happen occur with less force.