One fact of life is that air surrounds us. In fact, air is so ubiquitous that most of us don’t even notice it at all! In this homeschool science project, you’ll learn a little more about the power of that air pressure by using it to crush a soda can. Homeschool science projects like this one can help you to appreciate the power of nature – and the world around you.

Before you get started, gather together the following materials:
    •    One empty soda can (it must be aluminum)
    •    A two or three quart saucepan
    •    One pair of kitchen tongs

Once you have these materials together, you’re ready to get started with these steps:
    •    Fill the pan with water.
    •    Pour about 1 Tablespoon of water into the soda can.
    •    Heat the soda can so that the water within it boils. You’ll notice that when the water boils, vapor will escape from the can.
    •    Let the water boil for thirty seconds.
    •    Using the kitchen tongs, hold the can and invert it into the pan of water.
    •    Record your observations.

When you put the can into the water, you should have noticed that the can collapsed the moment it came into contact with the water. But why?

The can collapsed because the vapors caused by the boiling water in the can pushed the air out of the can through the mouth hold. The can was then filled with water vapor. When you cooled the can by putting it into the pot of water, the water vapor inside of the can immediately condensed, creating a vacuum. The partial vacuum had extremely low air pressure within it, which allowed the higher air pressure on the outside of the can to crush the can. By the way, if you like this experiment, you might want to download a free copy of the Homeschool Science Experiment Guide and workbook to find more great experiments like this one.

In essence, the can was crushed because the air pressure on the outside of the can was greater than the pressure on the inside of the can. This process is not terribly different than crushing a soda can with your hand; when you crush the can with your hand, you’re pushing the air outside of the can, causing the walls of the can to collapse.

In this particular homeschool science experiment, however, the water vapor caused the inside of the can to become essentially empty. Water from the pot could not flow into the can fast enough to prevent the can from being crushed by the pressure from the outside air.

How else does the air pressure all around us affect us? Are there ways in which the air pressure around you may be affecting you that you had not realized? How about air pressure at other altitudes? Not only is this experiment fun to perform, but it also helps us to understand the power of the environment in which we live.