Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: adrian on 26/05/2008 13:26:17
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adrian asked the Naked Scientists:
I'm Adrian, Romania and... well, I'm 28 and I'm reading Hector Servadac, by Jules Verne. And in this book a big piece from Earth is now flying through space. And there was a sea on this small planet.
It was getting very cold and there was no wind to make the smallest waves on the sea. Jules Verne has told us that if there are no waves, the water can keep its liquid state, form much more under 0 Celsius. And Hector Servadac asked a little girl to throw a snowball in the still water. Suddenly all the sea transformed its surface into ice.
Is it possible such a thing?.. Is the freezing point lowered if the water is still, without waves and it can turn quickly into ice if you make some waves?
Regards,
Adrian
What do you think?
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I doubt it ever happend that way but supercooling is a real effect.
http://en.wikipedia.org/wiki/Supercooled_liquid
There would need to be nowhere where the sea and the ice were in contact so it would need a very odd shoreline.
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adrian asked the Naked Scientists:
I'm Adrian, Romania and... well, I'm 28 and I'm reading Hector Servadac, by Jules Verne. And in this book a big piece from Earth is now flying through space. And there was a sea on this small planet.
It was getting very cold and there was no wind to make the smallest waves on the sea. Jules Verne has told us that if there are no waves, the water can keep its liquid state, form much more under 0 Celsius. And Hector Servadac asked a little girl to throw a snowball in the still water. Suddenly all the sea transformed its surface into ice.
Is it possible such a thing?.. Is the freezing point lowered if the water is still, without waves and it can turn quickly into ice if you make some waves?
Regards,
Adrian
What do you think?
Both are possible.
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Freezing rain is a really good example of this in real life though. Pure water will not form ice crystals until temperatures reach -40C. This is because, for reasons of energetics, the water molecules cannot align correctly to initiate ice crystal formation above this temperature. But, if there is a surface present then this can act as the key to kickstart the process.
So in clouds, for example, water can exist as super-cooled droplets. These can fall as rain but as soon as they land on something - such as your car windscreen - they instantly freeze, which can make for some pretty hair-raising driving conditions.
Usually, however, particulate matter in the clouds including dust, smoke, dandruff (yes, really!) and even bacteria act as nucleation centres around which water molecules can cluster and then begin to freeze.
Chris
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This is amazing..... ......Thank you very much for your answers...
So if I see a glass of this pure water in its liquid state at -40C and I touch it with my finger will it freeze?... This is amazing.. How quickly is it going to freeze?
I'm not very sure, but I believe that I saw in movies when a wizard touched with his magic stick a lake or a bucket of water and he transformed it into ice.
I will not rest until I'll see with my own eyes if it's possible this kind of magic... (I hope that not always if you have a contact surface it will act as a kickstart:)
Thanks!