[AKSH (OP)]

 []what is the reason behind the following experiment?

take one straw and water with salt in it.lit one end of the straw with a match stick.Then put that in the salt water for few seconds.When you take the straw the water turns in to ice with in a second

please post your reply immediately
thanks indeed

[Geezer]

Is the Vatican aware of this?

[Bored chemist]

What is "lightning straw"?

[RD]

when lightning straw in one end is being dipped in the water with salt and after few seconds when we take the hot straw out the water becomes ice

sounds like this youtube video ...

which looks fake, e.g. camera trick, or the water is supercooled which will instantly freeze when disturbed, or the "water" isnt water ...

[CliffordK]

I think we need more information about your experiment.

Supercooled liquids can behave in odd fashions.  There was something about supercooled beer...  one could give a bottle a good tap and it would instantly ice over.  

If you had supercooled salt water, it might only take a minor perturbation to force it to ice over.

(looks like RD beat me with the supercooled idea).

Was this being done in a sealed container?  There was a discussion here a while ago that a vacuum pump could cause enough water to evaporate to cause the temperatures to drop and create ice.

[damocles]

One way to do this "trick" is to warm up some sodium thiosulfate (hydrated) crystals. (It is readily available from photography supply stores -- used to be called "hypo", and it was the main constituent of the "fixer" in chemical process photography). At around 50-60 deg C they will dissolve in their own water of crystallization. The resulting solution supercools very readily. The solution will easily stay liquid down to room temperature in a moderately clean environment. It is likely that plunging the burning end of a straw into the solution will seed rapid crystallization, and turn the whole container to solid "ice" in a matter of a second or two. The whole process happens at or slightly above room temperature.

Afterthought:
If you are very carefully observant you can tell whether what is being done is this trick or a similar one. Although the rapidly forming crystals look like ice, there is a very important difference: the crystals will fall to the bottom of the solution. If real ice were being formed it would be floating to the top as it was forming. You would only have a second, but if you were careful you could see the difference.

[imatfaal]

Nice Afterthought there!  The initial crystals in the youtube video fall!  Look at around 50-52 seconds

[RD]

Nice Afterthought there!  The initial crystals in the youtube video fall!  Look at around 50-52 seconds

Better still the water droplets jump up into the upturned glass at 58-59 sec ...

i.e. the video includes a reversed (backwards) time-lapse sequence of a frozen glass defrosting.

[imatfaal]

Damn - I am too naive for these sorts of things.  Good Spot - and a nice trick