PURPOSE: To show the difference in density between soft drinks with and without sugar.

DESCRIPTION: Unopened cans of Pepsi and Diet Pepsi are floated in water. The Pepsi sinks, while the Diet Pepsi floats. The density of the Pepsi is increased by the dissolved sugar, which occupies space between the water molecules. Diet Pepsi has no additional sugar, and is therefore less dense.

SUGGESTIONS: See Question of the Week #199 for suggestions on using this demonstration to enhance class involvement. Ask your students the question: When you dissolve a cup of sugar in a cup of water, do you get two cups of solution? Question of the Week #306 is an interesting variant of this demonstration.

REFERENCES: (PIRA unknown.)

EQUIPMENT: Cans of Pepsi and Diet Pepsi, tank with salted water.

SETUP TIME: 5 min.