Molecular Motion: A Demonstration Classroom demonstrations of molecular motion are well known; however, demonstrations of the relationship of t,his motion and temperature are not readily available. The following demonstration fills this need. Using two beakers, fill one with hot water and one with cold water. Water from the hot water faucet and refrigerator chilled water are satisfactory. Introduce a drop of dye into each beaker as nearly simultaneously as possible. After trying several colored materials black ink seems to give the best effect. The dye in the hot water will disperse almost instantaneously while the dye in the cold water, although i t eventually disperses through the solution, remains undispersed. Students find the obvious difference in mixing rather startling. M. ELIZABETH DERRICK
Volume 49, Number 6, June 1972
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