[music, video clip of paper towel being dipped into superheated water, the water boils at each dip and stops at removal, music stops, cut to -]

Hank: [puts Yeah, turns out it's not always a great idea to boil water in the microwave. It is convenient, but it can also create superheated water, which is water that reaches temperatures above 100 degrees Celsius, without actually boiling.

It's caused by the way the microwave heats things up at the molecular level. Heat gets applied directly to the water molecules instead of to the container, like with stovetop cooking. [puts cup into microwave] And microwavable containers are usually smooth, which can prevent nucleation, the process that incites the water to go from liquid to gas.

The result is tiny pockets of super-hot water just begging to turn into steam, and they're only held back by the surface tension of the water. So when you break that surface tension, say, with a spoon or your tea bag... Boom.

But anything mixed into that water will help it nucleate, so heating up your drinks in the microwave is completely safe. As for this... [opens microwave door, looks inside] I think I'm just gonna let it... cool off for a little bit.

[end]