Question

To study the process of condensation by water bottle.

Answer 1

Just imagine this, say you are talked with carrying a load. If the weather suddenly gets colder (there are sudden cold wind blowing) you will start to clutch yourself trying to decrease your body's exposure to the cold winds. You will be unable to carry as much load as you would have been able to if the weather was more moderate and will drop off some of the load that you had been caring earlier.

It is a similar case with moisture in air. Hot air is able to carry more moisture than cold air. So, when the air cools down in contact with s cold surface it losses moisture which is deposited on the cold bottle as droplets.