[thedoc (OP)]

justin rylands asked the Naked Scientists:
   
I use still use my 30 year old stainless steel flask to keep my tea hot.

I make the tea and pre-heat the flask flushing it with boiling water 3 times. I put the tea in a saucepan,add milk (UHT semiskimmed) and sugar and bring it up to the boil on the stove, and then put it into the flask.  

6 hours later, at lunch time, the tea is still warm, but not so hot that you can't drink it it one gulp.

Then it occurred to me to use the microwave, instead of heating the tea up on the stove. I give it 1 min 15 seconds, which doesn't make it actually boil, before putting it into the flask.

6 hours later, at lunch time, the tea is still too hot to be able to drink it... to the point of almost burning my lips!!

Why does the tea stay so much hotter, for so much longer?

Does the energy, absorbed by the food in this way, not do damage to our body when it is ingested with the food?

I look forward to hearing your thoughts

With best regards
Justin Rylands
Cartagena, Spain.
What do you think?

[RD]

... Then it occurred to me to use the microwave ...

Why does the tea stay so much hotter, for so much longer?

It is possible to superheat water in the microwave : to raise it's temperature above the normal boiling point without it boiling.

Superheated water would contain more thermal energy than water heated to the normal boiling point, and consequently would stay warmer for longer , (all other factors being equal).