The Life Chocolatic – revisited

After The Life Chocolatic I wrote to the girls of Inky Circus for an explanation. Inky Circus is a very cool weblog if you are interested in science.

They actually passed the question on to their physics buff Alom and here is what he had to say about my the Life Chocolatic incident:

This is something that I have tried to do on purpose, believe it or not. The phenomenom is known as “superheating” and it’s quite spectacular to witness. Basically, due to the way a microwave oven heats things up, the liquid is warmed up beyond it’s boiling point, without the bubbling that we aassociate with boiling. Bubbles do not form in the superheated liquid, so high temperature vapour / gas is not carried away as it normally would be. This is an unstable state. As soon as you put an object into such a liquid (like a teaspoon), you make bubbles – lots of them very quickly, they explode out of the liquid and take lots of liquid with them. The same thing can happen if you put sugar in or sometimes even if you just knock the container.

Now this is an answer that even I understand. It certainly is quite spectacular to watch, and it is also quite spectacular how much you have to clean up afterwards. But it is interesting ! Cooking without bubbling, and I didn’t even do it on purpose.

A thank you to Alom and Inky Circus for the answer.

The Life Chocolatic

After The Life Aquatic experiment, I took it a bit further today. And I still don’t quite understand how it happened.

I filled a cup (a thick glass Bodum one) with cold chocolate milk (there is a snowstorm coming, so better be prepared).
I put it in the microwave to warm it up, for about 2 minutes.
I took it out, and gave it 30 seconds more on full microwave speed.
I took it out again, the cup was quite warm, also on the outside.
I placed the cup on my kitchen table.
I put in a teaspoon.

Now as soon as the teaspoon landed in the hot chocolate, it began to boil over ! Resulting in the cup nearly being emptied on kitchen table (the cup still standing!), hot chocolate milk flooding down my kitchen drawers, ending in a chocolate pool on the floor, of which Willy Wonka would have been proud. And of course there was chocolate milk in all my drawers too, on plates, in bowls, in my toaster, you name it. If I do something, I do it a 100%.

The thing is that I don’t quite understand how this could happen, from a physics* point of view.

(* Physics : The science of matter and energy and of interactions between the two, grouped in traditional fields such as acoustics, optics, mechanics, thermodynamics, and electromagnetism, as well as in modern extensions including atomic and nuclear physics, cryogenics, solid-state physics, particle physics, and plasma physics.)

But maybe some of you do ?

Whatever caused it – don’t try this at home kids.