An Implosive Idea

A soda can before….

…. and after

Here’s one for you: How does the soda can on the left end up looking like the one on the right—with neither human hands nor any machine ever touching it? The short answer is: physics—really cool physics, as the 9th graders in Andrew Lappin’s conceptual physics class were to find out today.

But you’ll have to wait until later to learn the real secrets of—The Imploding Soda Can!

To get some more clues about what’s going on here, take a look at these videos from Andrew’s class. Andrew demonstrates the safe and appropriate way to do this experiment for the students beforehand:

After students complete the experiment themselves, it’s time to start asking some really good questions about why the soda can implodes. After discussing the possible reasons together, the students test their working hypotheses when Andrew reveals the secrets:

Figure 1

Figure 1: Before the experiment, the soda can isn’t really empty—it’s filled with air. But the key to the implosion is to put a tiny amount of water in the can, as well. Without it, there is no implosion.

Figure 2

Figure 2: As the burner flame heats the can and water inside starts to boil, the air is pushed out—but the expanding steam causes a buildup of pressure inside the can.

Figure 3

Figure 3: When students quickly take the can off of the ring stand and plunge it upside down into a bucket of ice water, the steam condenses quickly and without the air the can violently collapses; voilà! An implosion.

The Take Away:

Principles of Physics + Awesome Implosion = Student Curiosity.  An equation for authentic learning.

~ By Steve Barrett, Director of Outreach, Teaching, and Learning

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