[LabLad_1]

I've been looking at this upcoming lab that we have coming up, and I just cant seem to wrap my head around it. The goal is to come up with an experiment to determine the temperature of water in a beaker, with only knowing that it is above 40 °C. I would greatly appreciate any pointers to how I can go on thinking about this.

In this lab, we will simulate a home water heater using beakers of water heated with
hot plates to an  unknown temperature that is greater than 40°C. Each group will
have available a thermometer that has the graduations above 40°C covered  so that
they are not visible. Using your 40°C thermometer and  materials available to you in
the lab, you must devise a way to measure the temperature of the water in the
beaker.

Thank you for your time

[Borek]

Think how to lower the temperature of water in such a way it will be still possible to calculate the original temperature.