Microwave superheating

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Administrator
Joined 2004
Paid Member
I put a standard ceramic coffee mug of cold in the microwave (900W) for 2 minutes. Picked in up by the handle and blistered my fingers. It was as though it had been in an oven. I used a hot mitt to transfer the water into my thermos and the outside of the thermos became very warm. It cooled back down after about 3 minutes.

Why did this happen?
Was there something about that particular mug?
Why did the water become so hot as to heat right through the thermos?

Enquiring minds want to know. :)
 
I swear to god, wine and brandy do taste better in crystal than in plain glass. But that is not my point today.

Water can certainly superheat in a microwave, but it usually bumps as soon as you move it. A bump is a furious boil, seemingly out of nowhere, when the superheated water is disturbed at all. I always dip a spoon into a container of water in my microwave before I pick it up, just in case.
 

PRR

Member
Joined 2003
Paid Member
Some ceramic heats more than others.

Someone who looks like me sometimes enters "22" instead of "2" and, if not noted, gets VERY boiled water; but half-empty cup and steamy oven.

The other alternative is that you discovered Cold Fusion with kitchen supplies.
 
Administrator
Joined 2004
Paid Member
Probably cold(ish) Fusion.

I boil water in the microwave for my coffee. With very clean glass the water never seems to boil, but it is super hot. A bump can set it off, as can putting in coffee grounds. I enjoy the effect.

But I've noticed what Cal has, some mugs heat more than others, as do some bowls and plates. What's in them that heats up? They will heat when empty, so it's not conduction from the food or drinks.
 
Someone who looks like me sometimes enters "22" instead of "2" and, if not noted, gets VERY boiled water; but half-empty cup and steamy oven.

Which after you wipe down the mess leaves you with a squeaky clean microwave oven. Ya know... When life gives you boiled water, make lemonade. Or something... :)

I've had microwaved water spontaneously boil when I submersed a teabag in it. I chalked that up as superheated water that got disturbed by the teabag and found it kinda cool. It reminded me of an experiment/demo done in chemistry class where a test tube of water is brought to a boil by only heating the bottom of the test tube. The liquid at bottom boils suddenly and shoots all the water out of the test tube.

Tom
 
Last edited:
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.