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Suppose you are in a boat on a pond and you are holding a small 10 lb weight. You drop the weight into the water. Does the water level rise, stay the same, or lower?


marked as duplicate by Gareth McCaughan Jul 18 '17 at 17:28

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When the weight is in the water

it displaces the same volume of water as itself.

When it is in the boat

it causes the boat to display a volume of water with the same mass as itself.


the weight is presumably denser than water,

when you drop it in

it will displace less water and the level of water in the pond will therefore sink.

  • $\begingroup$ Whoops, sorry for being stupid. I'm on mobile and couldn't find the search function easily. Clearly I'm blind, and that's no excuse anyway. $\endgroup$ – Quintec Jul 18 '17 at 17:55
  • $\begingroup$ No apology needed -- oversights are easy :-). $\endgroup$ – Gareth McCaughan Jul 18 '17 at 20:12

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