1. Fill a beaker about two thirds full with water at or near room temperature.
2. Fill a second beaker about two thirds full with cold water. (You can use ice cubes to cool the water, but be sure to remove the ice before adding the cold water to the beaker.)
3. Using a medicine dropper, place one drop of dark food coloring on the surface of the wataer in each beaker. Do not stir. What changes do you see in each beaker? How quickly do the changes occur in each beaker?
Question to Ponder:
How are your observations related to the effect of heat on the motion of molecules?