Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Neeraja Raghavan on 10/06/2009 09:30:01

Title: How can I boil water without killing a fish?
Post by: Neeraja Raghavan on 10/06/2009 09:30:01: Neeraja Raghavan asked the Naked Scientists:

Dear Naked Scientists:
Â
A glass jar is half filled with water. There is a live fish swimming in it.
How can we boil the water that is inside the jar, without killing the fish?
Â
Regards,
Neeraja.
Â
Dr Neeraja Raghavan

What do you think?
Title: How can I boil water without killing a fish?
Post by: Don_1 on 10/06/2009 09:39:10: Take the fish out!
Title: How can I boil water without killing a fish?
Post by: lyner on 10/06/2009 09:41:25: Presumably you mean "boil SOME OF the water"?
You could plunge a red hot iron rod in and boil some of it without frazzling the poor ol' fish.

Or do you put an insulated container with cold water in it into the glass (the other half) and put the fish in that?

Is the clue in "half"?
Title: How can I boil water without killing a fish?
Post by: Chemistry4me on 10/06/2009 09:53:46: Have you discovered some kind of super heat resistant fish species?
Title: How can I boil water without killing a fish?
Post by: Don_1 on 10/06/2009 10:27:59: Drop in a furuncle!
Title: How can I boil water without killing a fish?
Post by: lightarrow on 10/06/2009 15:37:55: Quote from: Neeraja Raghavan on 10/06/2009 09:30:01
Neeraja Raghavan asked the Naked Scientists:

Dear Naked Scientists:

A glass jar is half filled with water. There is a live fish swimming in it.
How can we boil the water that is inside the jar, without killing the fish?

Regards,
Neeraja.

Dr Neeraja Raghavan

What do you think?
Boiling point depends on external pressure...
If you connect your jar's opening to a void pump, at 4.58 mm of Hg (for example) your water will boil at 0.01 Â°C. At greater pressure the boiling point will increase.
At ~ 17 mm Hg, the water will boil at 20Â°C.
Title: How can I boil water without killing a fish?
Post by: RD on 10/06/2009 15:57:47: Compression and decompression would have to be done slowly otherwise the fish would die from â€œthe bends (http://www.spc.int/Coastfish/News/LRF/11/LRF11-StJohn.pdf)â€
Title: How can I boil water without killing a fish?
Post by: Bored chemist on 10/06/2009 18:12:21: A fish with a swim bladder would be in real trouble. Also, dropping the pressure until the water boiled would draw all the dissolved oxygen out of the water.
If there are fish that live near the volcanic vents at the botom of the sea they might just survive the heat but there's still a problem with oxygen. One of the best ways to remove dissolved gases from liquids is to boil them.
Title: How can I boil water without killing a fish?
Post by: Madidus_Scientia on 10/06/2009 19:19:24: I'll go along with Don_1's answer.
Title: How can I boil water without killing a fish?
Post by: lyner on 10/06/2009 19:21:42: lightarrow, you are a clever lad!!!!
Title: How can I boil water without killing a fish?
Post by: Bored chemist on 11/06/2009 19:17:54: I'm not getting into the debate on boiling fish alive just to check, so here's a related observation.
If you wrap an ice cube in metal wire so it sinks you can put it in a narrow tube full of cold water then heat the water near the top of the tube until it boils, without melting the ice.
Water is a fairly poor conductor of heat and, with this setup there's no convection current to distribute the heat.
Title: How can I boil water without killing a fish?
Post by: lightarrow on 11/06/2009 20:02:08: Quote from: sophiecentaur on 10/06/2009 19:21:42
lightarrow, you are a clever lad!!!!
[:I]
Title: How can I boil water without killing a fish?
Post by: DrN on 11/06/2009 21:07:27: Quote from: Madidus_Scientia on 10/06/2009 19:19:24
I'll go along with Don_1's answer.

Which one?

I'd go with the first one myself.
Title: How can I boil water without killing a fish?
Post by: lyner on 11/06/2009 23:56:17: Quote from: Bored chemist on 10/06/2009 18:12:21
A fish with a swim bladder would be in real trouble. Also, dropping the pressure until the water boiled would draw all the dissolved oxygen out of the water.
If there are fish that live near the volcanic vents at the botom of the sea they might just survive the heat but there's still a problem with oxygen. One of the best ways to remove dissolved gases from liquids is to boil them.
Use a little shark, then - no swim bladder afaik.
Title: How can I boil water without killing a fish?
Post by: Bored chemist on 12/06/2009 07:08:12: So it dies of anoxia rather than trauma.
Title: How can I boil water without killing a fish?
Post by: lightarrow on 12/06/2009 20:44:49: Quote from: Bored chemist on 10/06/2009 18:12:21
A fish with a swim bladder would be in real trouble.
Ok, what about steam distillation
http://en.wikipedia.org/wiki/Distillation#Steam_distillation
but used at the reverse, that is, instead of using water to lower the boiling point of an organic liquid, use an organic liquid to lower the water's boiling point? If you use more different phases, you can add the various vapour pressures and so you lowers even more every substance' boiling point. [8D]
Title: How can I boil water without killing a fish?
Post by: lyner on 12/06/2009 20:57:37: Are you suggesting getting the fish pissed during the exercise?
Just to prove the point, you'd only need to do it briefly and - hell, it's only a fish! You could eat it afterwards.
Title: How can I boil water without killing a fish?
Post by: lightarrow on 13/06/2009 13:29:38: Quote from: sophiecentaur on 12/06/2009 20:57:37
Are you suggesting getting the fish pissed during the exercise?
Just to prove the point, you'd only need to do it briefly and - hell, it's only a fish! You could eat it afterwards.
You could use inert chemicals, like perfluoropentane:
http://www.fluoromed.com/fluoromed/products/perfluoropentane.html
which has a boiling point of 29Â°C. (If you are worried for oxygen loss, you can add it to the mix).
Title: How can I boil water without killing a fish?
Post by: lyner on 13/06/2009 15:45:06: That would spoil the taste!
Title: How can I boil water without killing a fish?
Post by: Raghavendra on 15/06/2009 06:37:30: It's impossible
Title: How can I boil water without killing a fish?
Post by: Bored chemist on 15/06/2009 06:54:48: Quote from: Raghavendra on 15/06/2009 06:37:30

It's impossible
A rather odd assertion after several of us have said how it can be done.
Title: How can I boil water without killing a fish?
Post by: Chemistry4me on 15/06/2009 07:16:47: His arguement doesn't boil down to much in the end.
Title: How can I boil water without killing a fish?
Post by: Don_1 on 15/06/2009 07:22:55: Does Dr Neeraja Raghavan have a great secret he will be sharing with us some time? And why does he wish to boil some poor fish's life support system anyway?
Title: How can I boil water without killing a fish?
Post by: lightarrow on 15/06/2009 12:35:38: Another solution of the problem could be this: take the fish and transfer it to another jar with water, than boil the water in the first one. [:)]
Title: How can I boil water without killing a fish?
Post by: Madidus_Scientia on 15/06/2009 20:58:22: Don already said that, first reply!
Title: How can I boil water without killing a fish?
Post by: lightarrow on 16/06/2009 17:59:58: Quote from: Madidus_Scientia on 15/06/2009 20:58:22
Don already said that, first reply!
Gulp! Haven't even seen it! [:-[]
Title: How can I boil water without killing a fish?
Post by: thedoc on 17/06/2009 19:11:20: Listen to the answer to this question on our podcast. (http://www.thenakedscientists.com/HTML/podcasts/show/2009.06.14/)