I was just heating some water in a kettle, and after filling up my thermos bottle (so I'm not constantly running back and forth), I decided to pour the water back in to the pot and heat it back to a boil. I figured some of the heat would have been dumped into the glass in the thermos, and this would pre-heat it.
It took about ten seconds to bring the water back up to a boil. The kettle is electric, and draws 1500 watts. How much heat was sucked up by the glass inside the thermos?
Extra credit: What steps would you take to subtract out the effect of pouring a stream of hot water through room-temperature air?
Any wandering science teachers are welcome to steal the idea for this problem.
(If you're a science teacher, you'd jolly well better be able to work out the answers your own darn self!)
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