Lab #21.1 Heat: Chapter 21  Dance of the Molecules

Purpose
In this activity, you will investigate the difference between hot water and cold water—on the molecular level.

Discussion
The difference between hot things and cold things is referred to as temperature. The temperature of an object depends on the kinetic energy of the random motions of its molecules. A thermometer can be used to measure temperature, but we can’t always tell a hot thing from a cold thing just by looking at it. Consider a glass of hot water and a glass of cold water side by side. The water molecules in each glass don’t appear to be moving differently from each other. But they are. Follow the steps below to see the difference.

Required Equipment

2- 400ml Glass Beakers, Hot Water, Cold Water, Food Coloring.

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Student Worksheet   Teacher Notes

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The "hot" and "cold" water used in this experiment is just "tap water". The "food coloring" required for this lab is readily available at your local grocery or convenience store.