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Post by Chilehead on Apr 29, 2008 22:53:53 GMT -5
You place an empty glass on one side of a balanced scale and a one-pound weight on the other side. Then you fill the glass with water until the two sides are perfectly balanced. Now you put your finger down into the water withoug touching the glass. It makes the water level in the glass rise, but it doesn't overflow. What happens to the scale?
A. The glass side goes up.
B. The glass side goes down.
C. It holds still.
Explain why.
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Post by ken on Apr 30, 2008 0:14:19 GMT -5
it holds still. Your finger will not effect the weight..
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Post by Chilehead on Apr 30, 2008 8:57:35 GMT -5
That is incorrect.
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Post by RapunzeL on Apr 30, 2008 13:15:28 GMT -5
I'm gonna take a stab at this. The side of the scale with the glass of water would go down, because the act of putting your finger into the water would force it down, because of the water tension (I think that's the correct term.)
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Post by Chilehead on Apr 30, 2008 14:47:39 GMT -5
You are correct.
You are still pushing down on the water which will force the scale down.
Good job, Rap.
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Post by RapunzeL on Apr 30, 2008 17:56:32 GMT -5
Thanks! I was folding some laundry just now, & the words came to me. It's called "surface tension".
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Post by Chilehead on Apr 30, 2008 22:05:39 GMT -5
Technically you are pushing down with force equal to the weight of the water that your finger displaces.
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