Sunday, July 18, 2010

Science Sunday - Why Rockets Have Fins

While we were following the instructions from Rain Newcomb, and Bobby Mercer's Smash It! Crash It! Launch It! 50 Mind Blowing, Eye Popping, Science Experiments, to make our clothespin catapult, we saw another experiment, that answered a question we had left over from our water rocket experience. Why do rockets have fins?

First, you take a long balloon, blow it up, and release it, to watch it's crazy, looping path as it deflates. It's actually a fun game in itself, to release several balloons at once, and see who can get theirs across a net, or finish line.

Next, you cut three, or four triangular fins out of paper. The book says to use card stock, we tried cardboard, and found it too heavy, and then switched to typing paper.

Fold the edges of them, so you can tape them onto the balloon, equal distances apart. You, might want to use a clothespin to hold the balloon closed, while you're taping on the fins.

Then, let the balloon go again, and observe how the fins change the flight path.

We did this outside, with a slight wind, so our balloon didn't go straight, but it did make less sporadic loop de loops. Inside, we found it curved, depending on how the fins were tilted, but traveled in a generally straighter fashion.

Our water rocket seemed to do fine without fins, but we used a CokeZero bottle, that does have a sort of built in fin-type shape to it, anyway.

You can find more fun with science at this week's Science Sunday link-up, hosted by Adventures in Mommydom.

It's great to be a homeschooler.


Natalie PlanetSmarty said...

How fun! I really like your habit of testing different approaches - I can see that the best learning happens this way.

Ticia said...

The fins question made me think of October Sky, have you ever seen it? It's about a kid from a mining town who gets into rocketry, and he spends a lot of time trying to figure out the perfect shape for his fins.
And, I am so doing a balloon race game, as soon as I can figure out a good way to do it that doesn't involve me blowing all of them up.

Debbie said...

Great way of explaining why Rockets have fins!

Christy Killoran said...

Fun! I have never even thought about why rockets have fins before!

Anonymous said...

It looks like a very fun experiment! We may have to give it a try.