I think that all in all we had the right concept, we just didn't execute them in the right combination! When it comes to what features were involved, the first thing we tried was using 4 regular balloons filled with oxygen. We taped them on strings relatively close to the bottle so the balloons and the bottle would be close to each other. We were hoping this would provide a huge amount of drag and act as a glorified parachute of sorts... and it did! ... Just not quite in the way we'd hoped. We figured that if we pumped it up so there was a lot of H20 PSI (we put in about 70) then we would minimize the effect of the balloons drag on the way up and the amount of drag it produced on the way down would give us a good time. However, we only taped the balloons to the bottle with small amounts of scotch tape... so when all the pressure blasted the rocket upwards, the tape couldn't handle it and the balloons were left behind.
Back to the drawing board! We then decided to try and sticking a deflated balloon into the top of the nozzle opposite from where the water goes. We didn't really know why we were doing this, we just did it. We pumped a high amount of PSI - again around 70 - and noticed that this feature also worked pretty well. It didn't affect how fast and high the balloon shot into the air which was good because at 70 PSI it went pretty high/fast. However it did slow the fall of the bottle. We kept that idea in the back of our mind while we headed back to modify our rocket for the last time... our final ultimatum.
We had a helium tank and nearly 70 balloons. We did our research and found that 1 L of helium will lift 1 gram of mass. Each balloon could hold about 15 L of helium and our rocket was a little less than 20 grams. It was fool proof, or so we thought. So we filled 16 balloons with helium, leaving our tank virtually empty, and put strings on them and used hot glue and numerous rounds of duct tape to attach them to the bottle, we learned from our mistake of not securing the balloons the first time. We also removed two of the four fins from the rocket in order to make it lighter so the balloons could carry it. With no water in the bottle, the balloons allowed the rocket to float for about 2 seconds before falling at an extremely slow rate, so we felt very confident about our idea. We decided it would be best to not pump too much PSI into the bottle because we didn't want the balloons to come off and figured they could do all the heavy lifting on their own (since all the water from the bottle comes out as soon as its launched, and the balloons could support the empty bottle). We only put about 1/16 water in our bottle because we didn't want to take any chances of anything weighting the balloons down. This is where we went wrong... we only pumped 25 PSI into the bottle, so when we launched it it didn't go very high at all; and although it hovered for a moment before falling very very slowly - it just didn't have a high enough initial height to make enough of a difference and our final time was 4.9 seconds. OH WELLLL : (
For a physics project, I had quite a difficult time trying to understand how what we learned applied to this. I mean we didn't necessarily have any formulas we could've used to find how to make the rocket stay in the air or anything. However this taught me a lot about drag and pressure. Drag may be a good thing when it slows a falling object, but the reality that it slows an object that's accelerating upwards as well! It's sort of a double edged sword, and with something like balloons, you will have a very high amount of drag. When it comes to pressure, I think the main thing I took away from this project is that the more pressure you have the better! Don't try to manipulate your pressure to do what you think is right, rather just get as much pressure you can into your rocket, and then adjust your rocket accordingly. Make your rocket adjust to the pressure, don't adjust the pressure to your rocket... and TURN THAT SUCKER UP! The reality is, the more pressure you have, the higher your rocket will go and the longer time you'll have. I'm sure there are negligible acceptions to this but for the most part, pump away! Our second balloon launch - with the helium balloons - was extremely secured to the balloon, so had we pumped a high amount of pressure into the rocket, it would've had more air time up and therefore more time to come down (very very very slowly). As far as otherwise, apparently this project taught me that... no matter what we're all doomed to fail so too bad? NAHHH This project was a great lesson in patience and happiness. It was weird seeing how people were so emotionally attatched to this project! I mean after tthe launches (mostly failures) people were all depressed and gloomy! Why?! Chin-up, life goes on, the sun will still rise tomorrow and you'll be just as young and good looking. Taking things too seriously can be dangerous, so choose happiness... it's so much easier : ) In conclusion this was a really fun project, I kinda wish we'd had an extra day to play around with ideas just because it's fun to experiment but all in all it was pretty darn cool!
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