Water Bottle Rocket Weekend

Yesterday I had the pleasure of teaching a spaceflight class for 3rd, 4th, and 5th graders.  The major activity of the session was to build water bottle rockets.  I've discussed this in an earlier post from this summer, but today we tested something new.  First, let's see an official launch.  Below is the video I took of one student launching his rocket.  

As you can hear, the kids were quite excited when it launched.  A couple of pieces flew off this rocket as well.  The biggest story of the day, however, was the first launch, which is not shown in the video.  As the student was pumping air into the rocket, the rocket started to tip over.  Normally the base is very steady, so I'm not quite sure what happened, but suddenly it started to tip over...in my direction!  I start to tell the student pumping air, but just as I start to say something, the rocket launches...right at me!!!  I did a quick duck and it missed me.  Instant replay would probably have shown that the rocket cleared me by 2-3 feet, but it was a little too close for comfort!  

After that scare we had a blast.  One student asked if we could launch them with just air, no water inside.  So I said sure, why not?  We tried a couple of them.  They don't launch nearly as high, but the rockets are filled with "fog" after the launch.  Why the fog?  Due to the increased air pressure, a fog forms, which is cool to observe.  

In the end we had a blast launching several rockets.  As I've mentioned before, this is a cool activity for kids of all ages.