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Q & A: Floating Steel

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Most recent answer: 10/22/2007
Q:
Why does a steel (iron alloy) ship float on water, when the density of iron (7.86 g/cm^3) is greater than the density of water?
- Robin (age 18)
Austin, TX USA
A:
Robin -

Great question! The reason that a steel boat can float is because the boat isn't made entirely of steel. If you were to put a solid steel boat in the water, it would definitely sink, but the air inside the boat makes its total density much lower. Of course, if there were not enough air, and the boat sat too low in the water, some of the water could seep in over the top, taking the place of some of the air and making the total density higher. This is why boats will sink if they are tipped to the side.

-Tamara

(published on 10/22/2007)

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