- To show that an emf is generated when the junction of two differing metals is heated.
One thermocouple is kept at Ice temperature, and an initial measurement of emf potential is made. Then the "free" thermocouple is heated (fingers, then match). An increased potential on the meter shows an electron flow due to the differing electron activity of the two metals.
Constantan Alloy: 60% copper, 40% Nickel