GCSE Physics (AQA)

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Atmospheric Pressure

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Forces Pressure and pressure differences in fluids

Atmospheric Pressure

3:24 Depth and Atmospheric Pressure
Spec 4.5.5.2
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  • Atmospheric pressure is the force exerted by air particles in the atmosphere.
  • Air pressure results from gas particles colliding with objects.
  • At Earth's surface, atmospheric pressure is about one atmosphere or around 100 kilo pascals.
  • Humans typically don't feel atmospheric pressure due to body adaptation, unless in high or low pressure environments.
  • Atmospheric pressure's existence can be demonstrated by removing air from a container, showing that pressure inside balances the external pressure until the air is removed, causing the container to crumple due to unbalanced external pressure.
  • The strength of atmospheric pressure varies with altitude; it decreases as distance from Earth increases due to fewer air molecules and less gravitational pull.
  • Atmospheric pressure also changes with weather conditions and can vary at different points on the Earth's surface due to factors like humidity.
  • Significant differences in atmospheric pressure are noticeable when flying or at high altitudes such as mountain peaks.
  • At heights like those of airplanes or Mount Everest (8,000 to 10,000 meters above sea level), the pressure can drop to about 0.3 atmospheres.
  • Adaptations like pressurized airplane cabins and oxygen supplies for climbers are necessary due to the low atmospheric pressure at high altitudes.
  • Understanding and comparing atmospheric pressures at different altitudes is important for contexts such as exams.

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