We see water drops being on outer surface on objects like tumblers, vessels et cetera. It seems to be very small thing but it will be good if we know about it. We can observe water drops being on outer surface on objects when it rains or cool water is in the tumblers or we have the cool drink bottles which are cold, et cetera. The first one of the above is raining.
When it rains:
The outer surface of the glasses of windows becomes cool when it rains on the surface of them. On that time you can observe or you might have already observed inner side of the glass also being cool and its surface having water drops. When this situation appears, one question automatically raises in the mind. There is no gap between outer and inner surface of the glass but water drops are inner surface of the glass. What is it happening? It’s raining outside but water drops are inside of the glass. How have they come on to the inner surface?
The second one is cool water in the tumblers or vessels:
Actually, most of people use stainless steel tumblers or glass tumblers regularly. When cool water is in them, outer surface of tumblers will have water drops. They come automatically. Even you pour the water carefully into the tumblers there will be water drops on the outer surface of tumblers. How do they come? What is happening? Why are water drops on outer surface of tumblers?
The next one is cool drink bottles:
You might have observed many times the water drops being on outer surface of the cool drink bottles.
What is the reason? Why does it occur?
When cool water is in tumblers, their surface becomes very cool. This coolness spreads to outer surface of tumbler. When outer surface is cool, it cools the water vapour in the air which is around the tumbler. Owing to it, water drops freeze and stick on outer surface of tumbler, hence, the water drops appears on outer surface of the tumbler. This is the scientific reason for water drops being on the surface of objects when cool water or cool liquid in them.