You can arrange for a copper rod (or aluminium rod if copper is not available.). Put one end of the rod in one water tank and the other end in another tank. If the rod is required to be bent in a U shape , then take such a bent rod.
Measure the temperatures T1 and T2 in both the tanks before inserting the rod. Now wait for sufficient time. Measure the temperature of water in tank1, tank2 and the copper rod every 5 minutes or so.. Record them too. When the temperatures, become very close to one another, record the time taken and the temperatures. Now after some time like 1 hour, observe the temperature. You find that the temperature remains same.
This experiment shows that heat flows from hotter to colder water until both reach the same temperature.
Note the mass of copper rod. Now using specific gravity values you can calculate the rate of transfer from hotter water to the colder water.