1.   As the piston is pushed the near side opens and the air pressure closes the back flap.

2.   Manufactured by Austin House, these little gizmos are designed to help adjust on-board air pressure to the eardrums.

3.   Patterns of air pressure, surface winds and sea surface temperatures are all interlinked.

4.   The air pressure had dropped.

5.   The equipment records minute changes in air pressure.

6.   There were sensible, scientific explanations about the effect of the changes in air pressure.

7.   We could turn the glass upside down and sideways without having the water pour out because air pressure pushes in all directions.

8.   When we listen to music, for example, our eardrums vibrate with the rhythm of changing air pressure.

9.   The burette is placed in water and the air pressure equalised by opening and closing the tap.

10.   You have a lot of air pressure against you and you can use that to manoeuvre in the sky.