Assaulted by Tea

Ever hear of "exploding water"?  That old urban legend that heating water in a microwave for too long and then adding tea or coffee or something can cause it to explode? Well, it's a real phenomenon called "superheating."  In a nutshell, when undisturbed water is heated in a smooth container (with no scratches or chips), the water can get hotter than it's boiling point without actually boiling.  Then, when something disturbs the water (a spoon, tea bag, coffee, etc.) the water can instantly boil very violently in an "explosion" of hot water and steam.  Check out the science of it here.  This often happens with microwave ovens because they heat the water directly, and the containers we use in microwaves are usually glass or ceramic which are often completely smooth even at a molecular level.  Kettles and pots are usually not smooth and provide nucleation points for bubbles to form.

Why am I bringing this up? It just bloody happened to me while I was making tea!  I heated the water up in the microwave, took the cup out, put in the tea bag and FOOM!  Instantly sprayed with hot water and steam.  Fortunately being at such a high elevation (my parents' house in Prescott) meant that the boiling point was lower so I didn't get more than a minor burn on my hand.  But it was a hell of a surprise. 

For a demonstration, I call on the Mythbusters:

Needless to say, I think I'm going to make my hot water on the stove, or put something in the cup to prevent this from happening (a rough object in the water provides a nucleation point for the formation of bubbles).