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in class we are doing a bottle rocket and i have to find the ideal amount of pressure but my units must be in psi and they have to be under 90. I was wondering what does that mean?
- Gabriella (age 13)
"Psi" stands for "pounds per square inch". That says that over a square inch the pressure pushes with the same force that you'd get from a one pound weight. Typical air pressure is about 15 psi. You definitely shouldn't fill the bottle over 90 psi, because at higher pressure it might explode. Within those limits, the higher the pressure the more energy will be available to boost your rocket. Most gauges on bike pumps have a psi scale, so it's easy to keep track.
(published on 05/06/12)
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