This is about the balloon rocket
Does the shape of the balloon affect how far or fast the rocket travels.
Answers
The bigger balloons move farther because they can push more air. While all of your balloons pushed air out at roughly the same speed, the bigger balloons had More “fuel,” allowing them to exert force for a longer period of time.
BUT I DONT KNOW IF THE SIZE IS EFECTED OR NOT BUT HOPE WHATEVER I WROTE HELPED ;D
Answer:
The rocket balloon, whether attached on a string, or made into a vertical rocket (I had not see these before, but a google search suggested that they do exist) is a contained system. In the system, forces act on the main objects in the system. In this case, the force of air resistance pushes back against the thrust of the balloon.
When you change any variable in this system, the outcome will be affected in some way. Whether the acceleration of the balloon, its terminal velocity, or it’s time of acceleration (otherwise known as it’s impulse) is changed is not known until the system is observed.
The main factors affecting this system are…
The shape of the balloon and it’s aerodynamic properties. (also consider that as the balloon deflates, it’s shape does as well and it’s aerodynamic profile is constantly shifting).
The air density and the amount of drag on the balloon.
The “nozzle” through which the gasses in the balloon escape. (the open end of the balloon)
This image is a bit complex but it demonstrates what is going on well. As the balloon is inflated, it gains potential energy. Unlike in a rocket engine, where the pressure of the gasses on the inside is substantially higher, in a balloon, this difference is much smaller. The thing that contains most of the energy is the walls of the balloon itself. (like a spring, the walls stretch out and store this potential energy) The pressure on the inside of the balloon is higher than the outside, shown by the balloon expanding instead of remaining deflated, but not nearly as much as an actual rocket engine.
Some balloons will expand more than others, and some in different directions. A party balloon will have a different pressure than say, a balloon used for balloon animals (Which I will call a BA balloon for simplicity’s sake). While a party balloon might expand in all directions, the BA balloon tends to expand only in one direction, and stretches itself out. This would change the internal pressures on some level. (testing different kinds should reveal this difference)
Another thing to consider in this experiment is the profile (the view from the front) of a balloon. Essentially, the wider it is, the more drag it creates. (like putting your hand outside a car window. Horizontally, there is little resistance, but vertically, face on to the wind, there is much more…) A party balloon has more drag because it has a wider face, whereas a BA balloon would have a slimmer profile, and thus create less drag. Since less drag means more forces in the forward direction, the BA balloon would probably go faster.
While this is a simple explanation, there are many many other factors to consider if you really wanted to go in depth with the problem. Things such as,
1. The coefficient of drag changing over time as each balloon deflates
2. The amount of thrust each balloon creates due to it’s internal pressure… 3. how well the opening in the balloon can
direct thrust backwards. The opening can flap around when opened which is very inefficient. Maybe a BA balloon would do this less than a party balloon or visa versa…
4. The surface of a BA balloon would be more efficient that a rounded party balloon. Air creates less drag going along straight surfaces than curves ones…
5.Many many more variables.
Hope this gives you an idea of how these factors can effect this seemingly simple experiment! When you dive into the details of any problem, the complexities can be quickly exposed, hiding just beneath the surface. The best way to see how much each factor changes things is to do a test! Try out different balloon types, different pressures, paper “nozzles”, and other things! For fun, here’s an idea below for one to try.
Explanation: