# AP Physics and Water Rockets

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1. Oct 8, 2014

### kq6up

I love doing water rockets and I normally do them in the regular physics classes. However, I would like to do a water rocket lab with added rigor for the AP level course. I was thinking about having them write a iterator to factor in the drag and try to predict apogee. That might be too much for them though. Does anyone have any suggestions as to something in between just building 2l water rockets, and writing code to try to predict its apogee.

Thanks,
Chris

2. Oct 8, 2014

### Staff: Mentor

You could shoot the water rocket on a tile floor and have them figure out how far it will slide without friction and then compute the friction that occurred. You could also mount it on wheels and see how far it might go. Or you could determine its momentum when it hits another object.

You could tell them the Darwin awards winner with the jato on a car and crashing into a hillside. I think it was an urban legend but it sounds cool.

Another idea would be to compute whether it can hit a target that is either on the ground or elevated somewhat. This could bring in air resistance and how it affects trajectory.

3. Oct 8, 2014

### Simon Bridge

Well if you have students already doing computer modelling a lot, then trying to build a model that predicts range and apogee is doable.
The least you can do is work out the zero-drag case and demonstrate the difference.
You can also compare with other compressed-air projectiles.

4. Oct 8, 2014

### kq6up

@Simon Bridge Not a bad idea. I am thinking about offering the iterator as extra credit. That can use Maxima, Sage or Octave. They are free.

Chris

5. Oct 8, 2014

### Staff: Mentor

A simpler implementation of matlab is the freeman clone. I've used it when I needed to make some quick computations and charts.

http://freemat.sourceforge.net

6. Oct 8, 2014

### Staff: Mentor

Another more program intensive resource is the open source physics toolkit for doing simulations in Java.