Gold Bars
Science brain teasers require understanding of the physical or biological world and the laws that govern it.
There was a millionaire who loved collecting gold. He bought ten solid gold shapes from a man, but the man proposed a bet. He said:
"One of these shapes is fake. It is made from a metal that looks exactly like gold. The only difference is that it is 1 gram lighter per 10 sq cm. If you can find the fake, you can have all of the bars for free".
So the man weighed all of the bars, and to his surprise, they all weighed the same. Because of their strange shapes, he could not simply measure them. How can the man discover the fake without any measuring tools?
Answer
He could fill a bucket with water and place each shape in separately. Then whichever makes the water level rise most is the fake, as it would have to be slightly bigger to make it weigh the same.
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Comments
gingimo711
Aug 23, 2003
| i got it! we jsut studied the water displacement method in school! |
harsh_hsrah
Sep 09, 2003
| like it!! |
kshaw5
Sep 17, 2003
| riddle mistakenly uses area (cm sq) where it should be volume (cubic cm) seller's hint makes no sense otherwise. |
od-1   
Oct 03, 2003
| nice one |
Dustomatic
Nov 11, 2003
| It is simple density porblem....  is that what I'm learning in school.......... |
curtiss82 
Dec 24, 2003
| I think that Archimedes figured out that problem over 2000 years ago. |
eiennikirei 
Dec 25, 2003
| wow that was really easy
I like it  |
jetdjc15
Aug 27, 2004
| nice teaser!!!!  |
Blademaster
Mar 18, 2005
| This is Archamedes! Duh!    |
drussel3
Jun 17, 2005
| Basic Physics. |
fatjohn
Aug 05, 2005
| This one you either know right away, or you don't cause you have yet to take physics. The only problem I had with it was the fact you assume that a bucket (or any holder) of water would not be thought of as a tool. Sadly, in your solution, you are using the bucket exactly as a tool to measure the density of the objects. |
kibber
Sep 19, 2005
| i bet if you were alive 2000 years ago curtiss, you would have figured it out too right?
do you think your really smart?
i don't.
the answer to this teaser is DENSITY...that's all you had to write |
bookworm91 
Nov 22, 2005
| er would it also be possible to test the hardness of the gold with your fingernail? most metals are not soft enough to dent simply by pushing on them, but solid gold is. correct me if i'm wrong.
otherwise that was a really good teaser! |
dudebomb93
Oct 29, 2007
| NICE. |
tangled_brain
May 27, 2008
| correct me if i'm wrong, but size has nothing to do with it-density does.
The fake would be less dense, so even if it weighed the same, it would displace less water. Example: pumice floats because it is not very dense. drop a sample of gold of the same mass, and the gold would both sink and displace more water. |
Zag24
Jan 19, 2009
| You said "1 gram lighter per 10 sq cm" but you should have said 1 gram lighter per 10 *cubic* cm. |
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