You will need:
An ice cube
A matchstick
Salt
What to do:
Place the matchstick lengthwise on top of the icecube with part of the stick extending.
Wait a few seconds.
Now try lifting the matchstick up.
The matchstick is frozen to the ice. So the icecube can be lifted using a matchstick.
What's going on?
The matchstick becomes attached to the ice cube because the salt lowers the freezing point of water and melts the ice. The top of the ice cube quickly re-freezes which traps the matchstick. Simple eh? Plus a great trick that you can do whilst waiting for your food to arrive next time you're out for dinner.
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How does the ice cube refreeze? Isn't it always melting because the room temperature is higher then its melting/freezing point?
ReplyDeleteOnly those particles with enough energy to break the solid bonds will turn into a liquid, not all the solid ice particles have enough energy to do that - they need to get it from the surroundings. That's why it takes time for things to melt. So some of the ice is still below the melting point (especially those particles in the middle of the ice cube) - did you try the experiment?
ReplyDelete