Reflection....2

There were many ideas for the balloon car that we tried that did not work. One of these ideas was the general size of the car. Our original thought was to make the car big, so the balloon wouldn't interfere with the wheels on the car, but this was not a good idea because it turned out that the mass of the car was too much, and that the balloon could not produce enough force to cause acceleration. Another idea that did not work on the balloon car was that the balloon should have a straw to control the air flow out of the balloon. The straw actually reduced the force of the air coming out of the balloon because there was not a large enough opening for the air. Finally, the original box design for the car was not possible because it also created too much mass for the balloon to move. Overall, the balloon car's biggest problem was that there was too much mass, not enough force, and absolutely no acceleration (on the first trial, that is)

However, there were also many ideas that Anna and I concocted together that did work for the balloon car. First, our final, triangular shape not only decreased the mass of the car, but it also made the car much more aerodynamic. Having a smaller frame also decreased the mass, which meant that the balloon needed less force to move the car with a forward acceleration.  Another idea that improved the performance of the balloon car was the three wheel idea. Having one less wheel would also cut down on mass, and it would direct the car in a straighter line. These ideas that we used on the balloon car really improved the final result of the car.

The Balloon Car Project had many important lessons to learn. For me, the most valuable part of the experience was learning how to manage my time. I learned how bad it was to hold things off to the last minute and not begin thinking about something too late. I believe that if I had used my time better, Anna and I would have had a working car at the first test, and an improved car on time for the second test. Because I didn't work too well with my time, this hurt Anna's and my grade, and I will remember in the future the valuable lesson that the Balloon Car Project has taught me.

Reflection

Splatter car was a uniqe expirience for me! This project was about science in action, and I enjoy working on the blog, rather than a lab report. I actually really wanted to write a blog before this project, so the timing could not have been more perfect. Being able to take the information we learned in class and put it to use was really fun. I never really thought about all the science in a car before! I really love the creativity of this project! With trial and error Julie and I made a car worth blogging about!

Splatter Car was not perfect on the first try, and even on the final try. Our prototype was not very effective, it was too light to hold the balloon, it needed more mass to contain the force the balloon was exerting on it. The second problem that we had with our car was during the first trail; there was no forward motion in the car. We forgot about F=ma, aka Newton's Second Law. Our car had too much mass to be propelled by the force the balloon was exerting. The final problem we had with the car was that when we did the final testing, it veered a little to the left, so the force of the balloon was pushing the car more to the left. Luckily, Julie and I were able to overcome the issues with Splatter Car to make a fully functioning balloon car.


There is a lot of things I like about Splatter Car. It's race car-esque design helped combat fluid friction. We had non-CD wheels that did not wobble as much as the Cd's, making the car a little straighter (though it had arched). What I like most about Splatter Car was that it was very different from the other cars, but it worked well! We were able to use our knowledge of interia, Newton's Laws and more to make a stylish,working balloon car.

Newton's Second Law of Motion

Newton's Second Law of Motion states that the Net Force, or total force, is equal to the object's total mass (amount of matter) times its acceleration, or F = ma. When the balloon was released on the balloon car, the car did not let the balloon go as fast because of the added mass. The mass increased the inertia of the balloon, which caused the car to have less acceleration. When the mass is increased, the force needed to make the car accelerate, making the force and mass directly proportional. Force is also directly proportional to acceleration: when the force increases, the acceleration increases too. But when mass is increased, the acceleration goes down, making the two inversely proportional. So, when the balloon car's mass increases that of the balloon, the acceleration  decreases because the force remains the same coming out of the balloon.

Newton's First Law of Motion

Newton's First Law of Motion states that objects in motion will stay in motion unless acted upon by an outside force and that objects at rest will stay at rest unlest acted upon by an outside force. In the case of our balloon car, the car stayed exactly where it was until the balloon's forward force acted on it. Then, when the force of air decreased because there was less pressure in the balloon, the air pushing against the car in the hallway began to slow the car down until it finally slowed to a stop because the forces acting on it were balanced out.

Newton's Third Law In Action

How does Newton's Third relate to this project? Well, Newton's Third Law states that for every action there is an equal and opposite reaction.

The picture on the left shows how this law plays a part in this project.
The green arrow represents the action force, or the air coming out of the balloon. The reaction force (the blue arrow) is the air pushing back with the same force, in the opposite direction, on the balloon.
Because the forces act on different objects, the forces do not balance out.

This is how Newton's Third Law causes the car to start moving.

~Written By Anna Giles on Dec. 11, 2011

Friction and Splatter Car

Splatter Car works with three kinds of friction, sliding, fluid and rolling. The wheels roll along the floor, creating rolling friction. The car passes through the air, creating fluid friction. There appears to be no sliding friction in our car, but actually there is: the axles. The body is attached to the wheels by a glue stick, which slides along the piece of wood connecting the wheels. If there was no friction, the car would go on forever! Now that would make a nice grade!

Momentum, Velocity, Mass and Splatter Car

Why does Splatter Car move after the air is out of the balloon? It has to do with momentum, mass and velociity. Momentum, or amount of motion, is mass x velocity. So Splatter Car's mass times its velocity equals its momentum. The air being let out of the balloon causes velocity, and mass is the amount of matter in the car. This means that if mass in the car isn't too much, when multipled by the velocity, the momentum should carry the car forward after the ballooon runs out of air. Momentum plays a key role in this project.

The Second Trial

Great news! We have a working balloon car! Here is the video.

Cutting the mass really worked! Force x mass = acceleration, so when we cut the mass the acceleration went up! The car went 8.5 meters exactly! It just cleared the first row of lockers, as seen in the above video. I am so relieved that our hard work actually paid off. Unfortunately, however, there was a serious time delay between the test and the day it should have been tested. The real date should have been on December 6th, but we didn't have a functioning car that day so we tested it on the 8th, two days later, instead.

~Written By Anna Giles on Dec. 8, 2011

Let's Try This Again...

After the embarrasment of our car going backwards on the first trial, Anna and I realized that our car was just plain too big. As a result, we decided to cut down the zize of the base to a triangle with side lengths of 5, 6, and 6, instead of 12, 15, and 15. Then we removed the extra wood on the axles and made the front glue stick a lot shorter. Well this time I thought ahead and decided to test the car before it wen on the final trial. It was a lucky choice, because I learned that the Splatter Car curved horrendously and lost a lot of distance. After many trials and flying balloons, my dad pushed the car back to me to get it out of the kitchen (again), and to my surprise, it went almost perfectly straight! I realized that he had pushed the car backwards. So, then I just had to figure out where the tape should go and the car would be all set and ready for the second trial

The First Trial

We tested the car in class today, December 5^th. Here is the video:

As you can see, there is no forward motion! Zip! Zero! Zilch! So what happend? The answer is quite simple: too much mass. Acceleration= force / mass. Our mass was too large to handle the smaller force of the air leaving the balloon, so there was no motion. Tonight Julie is re-making the car while I work on the blog. Unfourtunately... we can no longer splatter paint Splatter Car because of our previous mass troubles. I know, it's heartbraking, but the science comes first!

~Written By Anna Giles on Dec. 5, 2011

Back To The Drawing Board

Obviously, the prototype didn't work too well. So, Anna and I met over the weekend to re-design the car entirely. We changed the materials from straws to a sturdier wood rod, which was purchased at $4.20. We decided on a three-wheel design, but still had no wheels. After fruitlessly searching the void called my basement, we found some old, unused tupperware lids that would work perfectly for our wheels. Then, we designed our car around these wheels, incorporating the shape of a drag-car. Eventually, we came out with a 20 inch long triangle with big wheels.

Being unable to use balloons at my house, we just pushed the car and made sure tha it went generally straight.

Then we closed our eyes and hoped for the best...

The Prototype

So, on Wednesday 11/29, Anna and I built the prototype for our car. It had a base frame of straws and other straws coming out of it to form a frame to hold in the balloon. Like this:

Anna and I were then hard put to find out how to put on wheels. So, we just tested how the car worked just like that.

Lots of testing short: It didn't.