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Science brain teasers require understanding of the physical or biological world and the laws that govern it.


Puzzle ID:#39051
Fun:*** (2.43)
Difficulty:*** (2.11)
Submitted By:AndrewWalkerAfi*****!
Corrected By:calmsavior




One ml of pure water is equal to one cubic cm and is one gram. But Jonie had a sample of one ml of pure water but its mass was slightly more than a gram. How can this be?


She had heavy water. Heavy water is pure water that is slightly heavier. Normal water has two hydrogen atoms and an oxygen atom. Hydrogen has one proton and one electron, but no neutrons. Heavy water is water with at least one hydrogen atom having one neutron.

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Nov 03, 2007

Good answer, but a more common explanation would simply to have water that is cooled a little. Your density statement is only precisely true at 25 C (and 1 atm). Water that is cooled to, say, 20 C will weigh more - per cc.
(Be careful, though - as water expands again, upon cooling, as it approaches the freezing point. But not around 20 C.

See? No nuclear chemistry needed for a plausible answer/explanation.
Nov 03, 2007

Thanks for the tip. I know that at 4 deegrees celsius is when water begins to expand.
Nov 03, 2007

This is also my first teaser.
Nov 03, 2007

very cute, never heard of heavy water, i hear of hard water but never measured it nice job for your first one
Nov 28, 2007

Nice teaser. I knew about heavy water and figured that was what you were talking about even though you did not stipulate STP (Standard Temperature and Pressure).
Mar 10, 2008

@electron. At STP it would be ice.
Mar 26, 2008

Hahaha! Yes! I just learned about heavy water last Wednesday in Chemistry class.

Well, I still got it wrong, but still.
Sep 20, 2008

Thanks for the tip. I know that at 4 deegrees celsius is when water begins to expand

Yes - which water... pure, impure, heavy?
Mar 09, 2011

I actually guessed both the heavy water and temperature difference options! I think they're both valid answers. For a first teaser, this is realllly good!
Jun 12, 2012

Heavy Water? Never heard of it. Or if I did, I forget it. I immediately thought that the water was cooled.

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