Why Would A Bottle Of Water Shrink As A Plane Is Descending From Altitude?

7 December 2018, 13:09

Picture: PA

Question: Why would a bottle of water shrink as a plane is descending from altitude?

Name: Anton

Location: Putney

Qualifications: Former RAF and commercial airline pilot

Answer: It is to do with differential cabin altitude in an airplane; you are typically cruising at 30-40 thousand feet and the cabin altitude is typically around 6-8 thousand feet so it is partially pressurised, like a reverse submarine.

If you’ve opened a bottle and air let air in, as you descend so does the cabin altitude so the ambient pressure around the bottle increases as the plane gets to sea level and becomes too much and effectively crushes the bottle because you’ve got less pressurised air within the bottle.