Thermodynamics...how hard can it be?

I have been inspired by my 'Lab Mates' (and givers of noms) to do an experiment today... to demonstrate
 
The first law of thermodynamics mandates conservation of energy and states in particular that the flow of heat is a form of energy transfer.


So I have been zipping around my tank to transfer energy to water molecules- and then checking the temperature... have been going an hour now though and I think it might take a while!