Question

How is the small cotton thread used to light the oil lamp(diyas) able to soak the oil in a reverse motion or backward when gravity will totally resist anything to move upward . then how is this possible?

Answer 1

It's due to capillary action.This effect is due to surface tension of liquids.The cotton here acts as a capillary tube. So the oil rise through the cotton. Even though there is gravity, the surface tensuon is more. So the oil rises.