Why does a plastic bottle is sealed at a high altitude change it’s shape when it is taken to low altitude

Agas is contained in a thick walled balloon when the pressure changes from 1.21 atm to 2.52 the volume changes from 3.75 l to 1.72 l and the temperature change from 293k to blank k

Why are pipes bursting in the in extremely cold weather?

What happens to the average kinetic energy of a gas when the particles of the gas collide against each other at a constant temperature and volume? explain your answer.