Listen to the hot tea episode of Domestic Science here:
http://www.bbc.co.uk/programmes/b07m7lmr
Full data footage is over here on my second channel: https://www.youtube.com/watch?v=-kZYxQpy3Ek
Stefan-Boltzmann Law
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan.html
The thermometer I used was the Signstek 6802 II, the cheapest dual channel thermometer I could find. But it turns out it is only $16.99 in the USA right now:
https://www.amazon.com/Signstek-Channel-Digital-Thermometer-Thermocouple/
آی-ویدئو