Water Rocket
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| Poster frame from video |
| Abstract | The trajectory of a water rocket is studied in some detail.
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| Portable | Yes | ||
| Principles Illustrated |
The upward acceleration of the boost phase, downward acceleration greater than g during upward freefall motion, near parabolic motion at the top of the trajectory, and downward acceleration less than g are all visible in the trajectory.
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| NCEA & Science Curriculum |
Extension |
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| Video |
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| Instructions |
Our water rocket has been modified from the usual. The bottle neck has a bung with a 5 mm hole to extend the boost phase long enough for it to be visible in the trajectory data. Other than that, it is a standard soft-drink bottle water rocket filmed from a distance. The motion is analysed with Tracker software which we use quite a lot and strongly recommend. Note there is some distortion in the video due to camera angles. We have a three hour activity built around the water rocket. It includes a rocket thrust test stand which we use to measure the engine thrust and then predict the speed of the rocket at the end of the boost phase and the maximum height of the rocket. The predicted speed at the end of the boost phase is reasonably accurate, but the maximum height is not. That's instructive. |
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| Safety | The rocket is traveling not much less than 100 km/hr on the way up and on the way down. It will do damage if it hits someone. |
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| Example Data | |||
| Credits |
This teaching resource was developed with support from |
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| Copyright |
