How do you determine Temperature of Water without a thermometer?

We will be given a cup of water that is greater than 50 degrees but less than 100 degrees, in physics lab next week and we only have a thermometer that goes up too only 50 degrees C, four styrofoam cups, a 100ml graduated cylinder, a balance, stopwatch, orted beakers, and graph paper and we need to determine the temperature of the water. Any suggestions or anyone know how to get the temperature?