Light a candle in a sturdy candle holder. Hold the spiral about 12 inches above the flame. Observe what happens. Rising heat will create a current of air that will make the spiral turn. The spiral stops turning because the flow of warm, rising air is interrupted.
Student constructs hypothesis.
Poke 3 holes into the bottom of a cup. Place one cup of highly concentrated blue ice cubes into the cup. Pour cold blue water over the blue ice cubes. Class should observe what happens from the sides and from above, and draw what they see. Continue watching the motion of the blue food coloring.