Archimedes principle

Daivik noticed that when he entered the bathtub, some water always flowed out. When he shared this finding with me, I said, "this is called Archimedes Principle". He asked me to repeat it and I pronounced it out for him slowly. He let the heaviness of the phrase sink in before asking what it meant. I said "When you get into the bathtub, 18 kilos of water will come out, and depending on how full the tub is, some of it might flow out of the tub". He got excited immediately and added, "and when I get out, all that water will come back in". I said, "yes, that is correct, but not all water will come back because some has overflowed the tub and it cannot get back inside".

I don't know how much he understood, but he thought about it for a minute and gave his verdict : "It is so funny".