Crush the Can

INTRODUCTION

The goal of this experiment is to show that air exerts pressure on the soda can.

MATERIALS

• 12 oz. aluminum soda can
• Hot plate
• Tongs
• Large pail of water

WHAT TO DO

1. Add water to the soda can so that the bottom of the can is just covered.
2. Place the can on the hot plate and allow the water to boil.
3. When steam can be seen coming out of the can use the tongs to pick up it up. Quickly turn the can upside down and dip it into the pail of water so that most of the can remains above water but the opening on the can is completely submerged.

QUESTIONS

1. What happens to the can?
2. What caused that to happen to the can?

SUMMARY

Before the addition of the water to the soda can, the can is filled with air. When water is added some of the air is displaced. Heating the water causes it to boil and the resulting steam expands inside the can, pushing most of the remaining air out of the can. When the can is cooled in the room temperature water, the steam changes to liquid water, which takes up much less space than steam. This change takes place while the opening of the can is under water, so no air is able to rush into the can to take up the extra space. The pressure inside the can is therefore much less than the pressure on the outside of the can, and so the can implodes.

SOURCE

"Science is Fun: Fundamentals of Physical Sciences." Janet Z. Tarino, OSU, 1990.

© S. Olesik, WOW Project, Ohio State University, 1999.