P has another simple science experiment whereby he used a cloth and rubber band to cover up the lid of a half-filled plastic bottle. Then he inverted the plastic bottle and showed me that the water did not drip.
He explained that the water molecules were like children holding hands. On the other hand for the cloth, the spaces between the cloth molecules were tiny. So the children holding hands could not get out of the "doors".
I asked him if water would drip if he were to squeeze or shake the plastic bottle. He nodded his head. I added that it was the same as if we were to give the children holding hands a push, they would be able to get out of the door.