This term has been about physics. Naturally, building a (bottle) rocket and launching it could help us learn about the forces that act on our universe. For the last few lessons, we have been designing and building a bottle rocket to launch with pressurised water. This would help us understand more about the centre of gravity on our rocket, air resistance and circumventing it with more aerodynamic designs and overall designing.
The equipment I used wasn’t much, but what little I did use, it was highly effective. The things I used in my build are as follows:
- A plastic bottle, one that isn’t too long and relatively symmetrical
- Two sheets of paper, one folded into a cone with a fine tip and the other used to fill the space left by the way the paper was folded
- A rectangular piece of cardboard to be used as a “skeleton” for the paper, giving it structure and the symmetrical cone shape
- Large amounts of tape, used to hold everything together
The steps I took to build the rocket are as follows:
- Get all materials needed
- Fold the large piece of paper into a usable cone shape
- Push one side harder against the other to create a sharper tip
- Tape the two large sides of the cone together to maintain it’s shape
- Use tape on the tip to ensure it stays sharp and also have a more structural sound nose
- Cut out a smaller piece of paper
- Use that piece of paper to fill out the triangular space left from the folding
- Use tape to attach the smaller piece of paper to the larger one
- Cut out a small, rectangular piece of cardboard slightly larger than the diameter of the bottle
- Tape the piece of cardboard to the bottom of the bottle (top of the rocket)
- Insert the paper cone onto the bottom of the bottle
- Tape it 2-3 times over while lowering where the tape touches each time to ensure the cone stays on the bottle
Although I didn’t add on as many things onto my rocket as the other people might’ve, it was for a mostly good reason that I’ll get into later.
On the day of the launch, we each put our rocket on an angled wooden frame with a pressurised water plug inserted into the open nozzle of the bottle to be used to launch our rockets. For my rocket, it had a flight time of 2.1 seconds and a distance travelled of 15.4m. Calculating the speed using the formula distance/time, we get an average speed of 7.33 mph.
Many things could be learned from the launches of not just my rocket, but everyone else’s. First, you could definitely observe a multitude of forces acting on each rocket, for example, the force of gravity pulling the rocket down as it flew (and while it was on the ground). Gravity is one of the first forces immediately considered when designing anything for flight and as long as you’re on earth, its effect is omnipresent. As a parallel of that, the newtons of energy from the initial launch gave each rocket enough energy to counteract/overpower the force of gravity for a short while and gain slight altitude. These two forces together for a short while after takeoff, balanced each other out as the force from the initial thrust weakened and let the rocket be in the air. As it weakened even more however, gravity regained control and each rocket fell from the air onto the ground as gravity became the dominant force again. Another force that acted on each rocket was air resistance or just the air itself. Firstly, although relative to the other forces it was quite weak, air resistance still made it so that each rocket was slightly slowed down from pushing against the air in front of it (drag). Secondly, if the rocket had wings, the air would push the wings and turn the entire rocket with the severity of the turn based on the size and placement of the wings. Turning the entire rocket is also related to another force, centrifugal force. Some of the rockets could be seen “spinning” rather severely compared to the other rockets and veering off course. The spin was caused by the air interacting with the wings, increasing centrifugal force as it spun and making it spin slightly more. A common misconception with rockets is that it needs wings, which is completely false. They are rockets, not planes. Wings are on planes because it helps them keep level in the air while also helping with turning. Most rockets’ goals are to fly as high as possible vertically. Sure you could try to use wings (fins) to stabilize it but these are bottle rockets, not tank rounds that need accuracy. Adding wings will add unnecessary weight and cause it to possibly spin and become a detriment overall to the rocket. The two rockets without wings were able to be tied in distance with a score of about 15.4m. The winged rocket with the longest distance achieved got a distance of… I don’t know I didn’t take note :p… but I overheard that it was near 12 metres which is substantially less than 15.4 metres. Not only that, my rocket in particular got the longest flight time with a time of 2.1 seconds. Another possible factor for my flight time was since my rocket was relatively long compared to it’s width allowing it to possibly fly farther because it wasn’t like a brick getting launched. Overall as the rocket flew, the net force would’ve changed to be favoring the thrust as the rocket started it’s flight, to favoring gravity again alongside possibly air resistance and centrifugal force towards the end of the flight.
Even if the act of flying bottle rockets is meaningless an act in it of itself, trying to find a way to improve how you could do it again could not only make you more intelligent, it could also be used to teach you about real rocket science and physics. Improvements for everyone’s rockets could be: far less weight, for example, many people made their rockets oversized wings and unnecessary additions. An example of this was the fact that many people used hot glue (unlike me heuhehuhe) which is not only more weight, it could mess with the aerodynamic structure of the rocket with the clumps of hot glue. Another improvement could be a longer streamlined body instead of, y’know, a brick. Even if you got left with a stumpy rocket, you could just artificially create length with a longer nose and more additions.
Going back to the start, flying bottle rockets has a surprisingly rich amount of details about physics you could learn from. Teaching you about mass distribution, weight efficiency, drag and what makes something aerodynamic.
is this a conclusion or another paragraph bro 
