Temperatures of refrigerators

Emilia Tiensuu wrote:
On the 28th of March we measured temperatures of refrigerators. We chose two pupils from energy team to measure fridges with class of water and thermometer:
First: we took glass of water
Second: we put thermometer in the glass of water and put it into the fridge
Third: after two hours we took glass of water away from the fridge.
The result: Arithmetic mean of temperatures was about 6-7C.
We found out that temperatures were ok and we don't spend too much energy.