Why does a needle floats on water but sink when some impurities are added.

Asked by Arun Iyer | 19th Feb, 2011, 05:29: PM

Expert Answer:

Dear student

The surface tension of clean water being higher than that of water mixed with impurities, it can support the weight of a needle due to its surface tension. By addition of impurity, the surface tension of water reduces, thereby resulting in the sinking of the needle.

 
Hope this clarifies your doubt.
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Answered by  | 20th Feb, 2011, 11:47: AM

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