Why does atmospheric pressure decrease with altitude? A6. There are fewer air molecules above you as altitude increases, so the weight of the air column decreases.

Here are the for a typical AQA GCSE Science P2 – 5.5 Activity Sheet (topic: Pressure and Pressure Differences – often part of the Particle Model of Matter or Forces unit, depending on the specific sheet).

What is upthrust? A8. An upward force exerted by a fluid on an object immersed in it (caused by higher pressure at the bottom of the object than at the top).