Q-Focus
(Rocket Science): Questions that we came up with included,
"What is rocket science?"
"How is this going to work out?"
and
"What will we need to consider in making these rockets?"
The first question was kind of basic. The second and third one were more important. "How is this going to work out?" was answered. The rockets we made turned out to be great in the end, except for North Korea. We actually managed to launch the rocket in the air, get it to land at an adequate distance, and have the egg still intact. By pumping air into a compressed chamber (the soda bottle), and having the rocket blast off as water escapes out of the nozzle, we accomplished in exceeding the distance of 30 meters required by the guidelines. The third question was also answered. We had to figure out what materials we were going to use to make the rockets. That took a great deal of thinking and pondering but eventually it all worked out in the end.
Making
the Rocket: It took us a few days to make three rockets. We
already had the names of the rockets in mind; all we had to do was build the
actual thing.
In order to build the rockets, we used:
- Plastic 2 L soda bottles (fuel/compression chambers)
- Duct tape
- Safety cutter
- Foam board
- Scissors
- Ziploc bags
- Toilet paper
- Eggs
- Water
- Graduating Cylinder
- Printer (for rocket designs)
- Construction paper
- Aluminum
Figure 1: Materials.
Notice how we had separate pieces of soda bottles, which were taped to the
whole soda bottles.
Figure
2: We had to cut the top part of bottles in this way. The piece would then be
taped to a full soda bottle that's flipped upside down.
Figure
3: Cone shaped pieces placed on top of soda bottles.
Figure
4: Aluminum balls to be put in cones.
The soda
bottles were fundamental to creating the rockets. We used six bottles in the
process; three for the body of the rockets, and three for pieces attached to
the rocket. We had them washed and cleaned before utilizing them. The duct tape
was necessary to securely seal different parts and support the rocket in
general. The safety cutter was used to cut out the fins for the rocket.
Accordingly, the fins were made of foam board. Scissors were used to cut out
pieces of soda bottles that were to be attached to the rocket (see Figure 2).
The eggs, provided by chickens from some farm, were kept in Ziploc bags in case
they broke as to prevent a mess from happening. Toilet paper was used to absorb
the impact made when the rocket hit the ground after launch, thus preventing
the eggs from breaking. Construction paper was used to make cones that would
make up the head of the rocket. This also helped in absorbing force in case the
rocket made a skydive into the ground. Water was fuel for the rockets. It was
pumped with oxygen (O2), increasing the pressure
within the rocket. In addition, a graduating cylinder was needed to measure the
amount of water that was to be placed in all three rockets. Lastly, the
aluminum was essential. We took large sheets of aluminum and compacted them
into small balls (see Figure 4), which we then placed into the cones (as
mentioned, made of construction paper). This helped to support the cones as
they hit the ground and absorbed some of the impact.
In
conclusion, the major decisions we had to make concerned how the rocket would
look like, how we would make it reach the required distance, and how we would
accomplish doing so without breaking the eggs inside the rockets.
The
Physics: Physics is a vital part of this rocket lab. Major concepts
such as acceleration (velocity is changing), force, and velocity (measure of
speed) are examples of things that we've learned that are all included. If we
know the force and acceleration, we could find what the force is. This is where
Newton's laws of motion play an essential role; Newton's second law (F=ma) is
particularly useful. As the rocket is launched (person pulls pin), the rocket has
a large amount of acceleration as the fuel (water) explodes out from the bottom, the nozzle.
The pressure building up in the rocket helps it to increase in acceleration
when the rocket is released. In addition, the rocket must "fight"
against the force of gravity (9.8 m/s^2).
Other physics concepts that are considered:
- Inertia: resistance of an object to a change in its state of motion.
- Air resistance: forces that oppose an object moving in air.
- Projectile motion: object moves along a curved path due to gravity.
A visual representation of the forces enacted on the rocket:
Practice Launch Photos: {Me with camera}
Kenneth
doesn't look too happy.
Kenneth
isn't very good at this.
Rocket
lands. Egg survives! Notice how the cone collapsed but the rest of the rocket
was largely unaffected.
Results:
We
made three rockets. "North Korea" turned out to be just like the
actual thing: it failed. It reached the shortest (15m) out of all the rockets
launched, including the ones from second period. Again, it was an utter letdown.
The other two rockets were much better. Iran reached the farthest distance at
82 meters, China at 68 meters. So the average of the three turned out to be 55
meters. None of the eggs used were broken in the process. All three rockets
were set at 35 degrees. All three rockets had 800 mL of water for fuel. We
chose this number because we wanted to have a substantial amount of fuel and
have some weight on the rocket. At the same time, we needed to make sure that
there wouldn't be too much weight as to prevent the rocket from not reaching
its maximum distance. Overall our choices for angles and water quantity were
good. Two out of three of our rockets succeeded in meeting and exceeding the
distance required. We believe that the only reason North Korea failed miserably
is because we didn't structure the body of the rocket correctly, as we had done
with the others. We later found out that it was loose and unstable, and this
probably contributed to its malfunction.
Summary...
What went RIGHT:
- Rockets were made on time
- Average distance exceeded requirement (30 meters)
- Eggs survived
What went WRONG:
- North Korea
What I learned: It's possible. It is actually possible to have something nearly made of plastic and water fly high into the air and land at a distance. Of course, this was more than just plastics and H2O; physics was part of the problem. Physics and concepts that are fundamental in physics, such as force and air flow, all played a major role in helping us get these rockets to work out the way they were supposed to. In the early stages of the project I thought that this was simply crazy, even bizarre. But I was mistaken. The results of our rockets were both surprising and satisfactory.
