Hot coffee
I have a gigantic coffee mug, which holds at least two normal-sized cups' worth. I like to drink my coffee slowly over the course of the morning, which unfortunately often results in it going cold. Since tepid coffee is the juice of Satan's socks, I ordered one of those heating elements that you plug into your USB port and dunk in your drink. It even clips handily onto the lip of the mug.

Unhandily, it doesn't heat your drink in the slightest. I'm convinced it actually leeches heat from the liquid in which it is immersed. Maybe I should get one of those old-fashioned kettle-elements-on-a-cord that people used to take on holiday with them in order to boil water in hotel rooms.
( .Yeti., Thu 29 Sep 2011, 13:40, 11 replies)

Or, indeed, a thermos flask?

( Another_tragic_case wished he hadn't eaten all the cake, Thu 29 Sep 2011, 14:05, closed)

No, can't be bothered with that.
Having to unscrew and pour every time would get on my wick. Plus, in order to hold enough coffee, it would have to be so big it would obscure half the screen. I'd get one of those self-sealing mugs with the sliding tongue but I can't seem to find one large enough.
( .Yeti., Thu 29 Sep 2011, 14:10, closed)

Or ...
reduce your coffee habit.
( Je suis un vagabond is an unfunny, up your own arse middle class knob, Thu 29 Sep 2011, 14:11, closed)

BURN THE HEATHEN!
I'd light the kindling myself if only my hands would stop shaking.
( .Yeti., Thu 29 Sep 2011, 14:13, closed)

Or do what I do - take one's tepid cawfee to the microwave, nuke for 60 seconds, problem solved....
(Maclir, Thu 29 Sep 2011, 14:37, closed)

"holds at least two normal-sized cups' worth"?
That'll be a normal size mug, then?
( monster munch person, man, woman... camera... TV?, Thu 29 Sep 2011, 14:40, closed)

Tométo, tomahto
I call anything bigger than an espresso thimble a cup. Anything with short sleeves is a t-shirt and anything with long sleeves that isn't a shirt is a jumper.
( .Yeti., Fri 30 Sep 2011, 6:27, closed)

Just get a smaller mug
(Freakmandu, Thu 29 Sep 2011, 14:42, closed)

Let's do the maths
USB ports can supply 5v, 0.5A. That's 2.5W.

A typical cup of coffee is 250ml of something with a density of 1kg/l and a specific heat capacity of 4200 J/kgK. Put that together and your cup of coffee has a heat capacity of 1050J/K.

So 2.5W is enough to heat a cup of coffee at around 8.6 degrees C per hour. Since a cup of coffee will cool from around 100 to around 14 in an hour, the best you can hope for is a 10% reduction in temperature drop.

Or as we heat transfer scientists say, "fuck all".
(ubergeekian, Thu 29 Sep 2011, 18:34, closed)

can't see...blinded...by science...

( .Yeti., Fri 30 Sep 2011, 5:17, closed)

^ this..
Is brilliant.
(danniekavanagh did nothing constructive on, Fri 30 Sep 2011, 16:00, closed)