Question

One winter evening, after drinking a soda, you tighten the cap back on its empty 20 ounce plastic bottle and leave it in your car. Returning to your car the next morning, you find that the bottle has collapsed, looking like it was crushed overnight.

In terms of heat and thermodynamics, explain what has happened to this bottle.

Answer 1

When the bottle was closed after emptying the liquid inside it the space inside the bottle was occupied by the air at the evening temperature, when the bottle was kept aside throughout the night where it experienced fall in temperature, then the pressure of air inside the bottle decreased as ( pressure is proportional to temperature "Boyle's Law") and since the environment outside the bottle exerted pressure on the walls of the bottle it collapsed, This phenomenon can also be explained by Charle's Law as the temperature of bottle decreased the volume of air inside it also decreased and hence it shrunk and the bottle collapsed.