Materials: thermometers*, plastic cups*, a clock.

Place thermometers in four plastic cups. Leave one cup dry; add 60 milliters (2 ounces = 4 tablespoons) of tap water to one; add 60 milliliters of hot water to one; and add 60 milliliters of very cold water to one.   (Please note how "hot water" and "cold water" are defined). Measure the temperature of each cup right after you fill them, and then every few minutes for 15 minutes, entering your measurements into a table. (It is a good idea to stir the container briefly with the thermometer before you make each measurement.)

Make a line graph showing how the temperature of each cup changed during the observation period, with the time as the independent variable (measured along the horizontal axis) and with the temperature as the dependent variable (along the vertical axis). Put all four graphs on the same grid, to make it easy to compare them.

At the end of the activity, write a commentary on what you learned:

• How different are the temperatures at the end?
• What does your graph suggest will happen to the temperatures after a long time?
• If you measured the temperature of other objects in the room, what temperature would they be?
• What does this activity have to with with the previous one?
• When the hot water cooled down, where did its thermal energy go?

Check the box when you are done:   Science content: thermal equilibrium