Air Pressure Demonstration

On Tuesday, we attempted to do the air pressure can crush demo in my first period class.

It didn’t work.

Sometimes in the lab, things just don’t work as planned. I think what happened is there was not enough water vapor in the can before I turned it over in the water. My student teacher explained to my students what should have happened, and I found a video to show them.

But it still wasn’t the same as them seeing it first hand in our classroom.

So yesterday, they asked if we could try again. How could I resist. We did, and it worked! And of course, my students loved it so much, they wanted to see it a second time. The second time, we filmed it. The video is below.

Did you hear all of the “Wait! Wait!”s in there? My kids were pulling out their cell phone cameras so they could video it as well. Isn’t if fun when kids get so excited about science? And it wasn’t just all fun and games; my students found a much better understanding of changes in air pressure, temperature effects on gases, and density of air versus water vapor.

It was a great day!

By Janelle

Space geek, science nerd extraordinaire. That's me! Want to know more, visit the About page.


  1. Your students learned another valuable lesson. It has been my experience that when things don’t work the way you expect them to, you actually learn more. If you can explain why the experiment didn’t work as expected, then you show that you have more than a basic understanding of the principles involved.

    When I go to programming or computer classes, I always look for people who are having problems with a lab or an assignment. If we can work through the problem and figure out what’s going on, both of us learn more from that than we would if we had simply completed the task!

    Failure in a lab setting is not such a bad thing. Ask Thomas Edison, among others. šŸ™‚

    1. Thanks for stopping by, James!

      I agree that things not working correctly is very valuable. It was also good experience for my student teacher who attempted for the first demo. It also allowed us to revisit the concept of air pressure and density of gases during the next class period. Plus, you can hear how excited my kids were when it did work.

      When my students do their science fair projects, one thing I try very hard to emphasize is even when you do not support your hypothesis, you have conducted valuable research. We also discuss sources of error, which helps them analyze why they got the results they did. Critical thinking is such an important skill! I hope I am helping my students master it.

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