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Watch this one together

~5 min · materials: a square of aluminum foil and a sink or bowl of water (optional, for the hands-on check).

Does the shape of a piece of steel decide if it floats?

At the kitchen sink, reshape the same square of aluminum foil into a tight lump and then a wide hollow form. Same metal, same weight — predict whether changing only the shape can change what the water does.

Talk about it

  • Same foil, two shapes: crush it into a ball and it sinks, flatten it into a boat and it floats. What changed?
  • Why does pushing a beach ball underwater feel so hard?
  • If you cut a hole in a floating boat, what do you think happens, and why?
Watch it together

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