When my housemates and I were having dinner yesterday night, someone brought out some interesting questions:
- There is a boat on a lake, and inside the boat there is a guy and a stone. The guy throws the stone out of the boat. Will the water level of the lake rise, fall, or remain the same? Here the water level is in reference to the land, not the water level of the boat. Also, assume that the total water volume of the lake is constant.
- What if instead of a stone, the person breaks a wooden plank from the boat and throw it into the lake? Assume that the plank is less dense than the water.
- You are swimming on the lake. You peed. What will happen to the water level of the lake? What if you are diving instead of swimming?
- You are sitting on a bath tub with the plug on and some water in the tub. You peed. What will happen to the water level?
- Same with 4, but instead of peeing, you poo-ed. What will happen to the water level? What about fart? (Thanks to Thow Kong for the brilliant question. :P)