Darrien Spitz Reflection

During the process of making the balloon car, many ideas worked, but many also did not. As one of our first designs, we tried using cling wrap on the outside of the car to make it more aerodynamic. Once we tried it, it was clear that all it did for the car was add weight and mass, although it could have been a good idea it was quite ineffective. Another idea was using erasers as the axles for the car, so that the wheels would stay in place. Even rolling the car on the table showed that the wheels stayed in place, but that they were not straight, and would not be straight unless we put them in perfectly. Even though we made many other mistakes, this one made us start over. To make the mass of the car less, we put the wheels closer to the car, so that there's less skewer involved. The problem with this idea is that the wheels would hit the car, so the car would slow down more and more. The wheels weren't perfectly straight, but they kept the car going in a straight line, and this design made it impossible for the wheels to move freely.

            There may have been many problems, but there was also some success. Instead of using erasers as the axles, which are curved and ineffective; we used cork, which is flat and hard enough to keep the wheel from twisting. Another good idea was using CDs for wheels. That was our idea from the start and we knew it would be good because CDs are thin and smooth, which means less friction. CDs were slightly heavy, but a little extra weight didn't slow the car down too much. Another idea that we had from the start, was using an egg carton. An egg carton is light, aerodynamic, and relatively small. The egg carton was very effective, and did not impede the motion of our car by very much. Overall, during the design process of the car, there were good ideas and bad ideas, but in the end everything worked out okay.

            The most valuable part of the learning process, was dealing with failure to create success. It's hard to try to create something when it has failed a few times, but the lesson of this was to never give up. This project is based on your knowledge of motion, and how to use that in real life. Most people have never been given a project like this yet, which is why it is so difficult. Knowing how to use something in real life is hard, because you don't know how to manipulate real things to create a finished result. Testing different designs, and not knowing which will work and which will not is extremely hard. This project has taught my group how to deal with failing to create success, and to persevere until we do.

Carlie Thibeault's Reflection

The balloon car brought many challenges and rewards, but first we had to go threw the hard stuff to get to the easy stuff. Me, Tia and Darrien had to make at least 2 cars until we got the car that actually worked. So obviously that brought many challenges, for example: the day me and Darrien met up at my house, we had to build the whole car and the most challenging part about that was trying to figure out how to make the wheels stay on straight. What we did is we tryed using erasers in between the CD whole to stick our scewer in, which is where the wheel would go on, but when we finally tested it, and it would turn to one side then they would wobble to the other, that made the car unstable which would effect our trial run at school, so we started all over. Another time when me, Tia and Darrien met up at my house is the day that we almost got our car to work. We tryed using corks for the scewers to go in this time. It actually worked! When we tryed testing it at my house though, the balloon got in the way of the tires so the next day at school we had to think of a plan to make the balloon so it doesn't hit the back tires. The last obsticle was the blogs, the blogs weren't terribly difficult but they caused some challenges. The most challenging part about those is was trying to think of all the stuff we learned in science and try to relate it to the balloon car project. In the end we got an amazing reward; a A+ for going 22 meters!
The most valuble part of this learning experience was learning about all of Newtons Laws and seeing how they actually came in play with the balloon car. When we were learning in class about the three laws, i didn't really uderstand it but when we made the car it actually helped me understand it better, for example: the first law, an object at rest will stay at rest until acted on by a force and an object in motion will stay in motion until acted on by an unbalanced force, when the car moved I noticed that the air inside the balloon was hitting against the air on the outside, so i related that to Newtons first law of motion. Also i lvoed working with Darrien and Tia. We worked really good together and we got along real well. Overall the project was really fun and I learned so much new stuff. We all got a great reward and a very valuble learning experience.

Analysis Questions A-E

A.) Newton’s first law of motion explains why the car started moving and why the car came to a stop. Newton’s first law of motion states that an object at rest will remain at rest and an object that is moving at a constant velocity will continue moving at a constant velocity unless acted upon by an unbalanced force. When the Balloon Car started to roll, the air inside the balloon came in contact with the air on the outside. The air inside of the balloon pushed out against the air on the outside causing the balloon car to accelerate. About 40 seconds later the balloon car stopped. It stopped because the balloon had no more air to push against the air on the outside. Therefore the air inside the balloon and the outside air would be considered unbalanced. Newton’s first law of motion proves that once the car comes in contact with another force that is unbalanced, the car will move, but once the air inside of the car is gone, the air on the outside won’t have to fight with another force causing the car to come to a complete stop.

B.) Newton's second law of motion explains how the mass of my balloon car affected the acceleration as the balloon car just started going. Newton's second law of motion states that the force of an object is equal to the product of its mass and acceleration, which is displayed by the equation F=ma. This law implies that the equations m=F/a and a=F/m are also true. When mass is increased and force stays the same, then acceleration will decrease, so acceleration and mass are inversely proportional. This information is incredibly important considering the force applied on the balloon car will always be the same because the 12" balloon is the only force applied. While creating the balloon car, the only factor that we needed to question from the second law is mass. The group had to make sure that the mass was less so that the acceleration would be greater. Newton's second law explains that if my balloon car has a lower mass, then the acceleration will be greater.

C.)

Momentum, the product of the mass and velocity of an object, is present in the balloon car project. The mass of the balloon car affects how fast the balloon car goes because the more mass the more momentum there is. This makes mass and momentum directly proportional. The velocity of the balloon car also affects the momentum. The faster an object is going the more momentum it has, therefore also making velocity and momentum directly proportional. The balloon car continued to move after the air had blown out of the balloon because the air had given the car momentum to keep on moving. The air in the balloon had pushed out of the balloon which caused the balloon to push on the air. This made the car accelerate forward. The velocity of the car slowly decreased because of the friction of the air and the ground, causing the momentum to slowly decrease. Mass and velocity affected the balloon car’s ability to keep moving through the hallway.

D.)

Newton’s third law of motion, which states that every action has an equal and opposite reaction, is applied in the balloon car project. This law is applied firstly by the air being pushed into the balloon when it was blown up. The air on the inside was exerting a force on the air on the balloon, while the balloon exerted an equal force on the air. The first object in this pair of action and reaction forces is the air, while the second object is the balloon. Another time when the balloon car represented Newton’s third law of motion was when the first object, the wheels of the car, pushed against the ground, causing the reaction force of the ground, the second object, to push against the wheels. This caused the car to move forward and accelerate across the floor of the hallway in which it was tested in. The force in the third law of motion relates to the first law of motion because the force of the car moving would just keep moving unless there had been another force to stop it. The balloon car was stopped by the friction of the floor against the wheels and the friction of the air on the car. Newton’s third law of motion is demonstrated multiple times in the balloon car project.

E.) All three types of friction affect the motion of the balloon car, so the car is designed to allow the most motion possible. Friction is the force that one surface exerts on another in the opposite direction that the object is going when the objects rub against each other. Friction will slow the balloon car down to a stop, and will slow the car down faster if the friction is stronger. The strength of friction is dependent on the types of surfaces involved and how hard the surfaces push together. There are three types of friction: sliding, rolling, and fluid. Sliding friction is the strongest friction and is caused when one object slides across a surface. Sliding friction is the strongest because there is most likely more surface area involved, meaning there is more space where friction can be created. During the design process, my group made sure there was as little sliding friction as possible. To do this, we just made sure nothing touched the ground other than the wheels. This is important because nothing important to the function of the car needs to touch the ground, so we want to make sure that this especially does not impede our cars motion. Rolling friction is the second strongest friction and is caused when one object rolls on another. There is less friction involved in rolling friction because there is less surface area for the object to come in contact with. Rolling friction is required in a car's motion, but the type of wheel that is on the car can determine how much friction will be involved. During the design process of the car, our group chose to use a CD for the wheels because a CD is thin and smooth, which means that only a small amount of surface area touches the ground. Fluid friction is the weakest friction and is caused when a fluid, a gas or liquid, rubs against a surface. Fluid friction is the least strong friction because it keeps objects from touching one another. The type of fluid friction that will affect the car is air resistance. Air resistance is affected by the area of the car, so the bigger the area, the stronger the air resistance. While designing the balloon car, we made sure that the car allowed as much air pass through it as possible, so we used an egg carton. The egg carton was small, smooth, and let air pass through it easily. Overall, friction slows the balloon car down, so the design of the car has to make the friction as weak as possible. The three types of friction each impede the acceleration of my balloon car, so the car is designed so that the friction is weak. 

Trial #2

On Tuesday, December 6th, Carlie, Darrien, and Tia were ready to test our balloon car for the second time. Before testing the balloon car we got about 5 minutes to fix any changes, but we didn't have anything that needed to be changed or fixed. With the 5 minutes to spare we tested the car in the back of the Science room, it moved perfectly. Then we got in line to test the car. Tia  blew up the balloon and then Darrien stuck it on, attempting not to close the balloon. Darrien got the balloon on the car very easily and than Tia let go. The car went further then we expected. We were all very happy with the out come. 22 meters was definitely better than .6 meters.

Trial #1

On Monday, December 5th, Carlie, Darrien, and Tia tested their balloon car. Before the balloon car was tested we got about 10 minutes to fix anything that broke or needed to be changed. On our car, during the traveling from home from school, one of the wheels in the front got ripped off, so we all had to fix that. We stuck some tape there and it seemed to hold pretty well. Finally, we had to test the balloon car, so we got ready and put the balloon on the car (by taping it), as we let the balloon go it moved only .6 meters. As it turns out Carlie accidently taped the balloon shut, so it couldn't move anywhere, alowing the air in the balloon to move slowy out. We were all thankful that we had a second trial after seeing that are car only moved .6 meters.

Design Process: Beginning to End

At first we thought that making our balloon car small would be better, and it would've except for the fact that the wheels hit each other because they were too close together. Also, we had too much tape and cling wrap on the car, so it weighed too much, and did not move. When we tested this idea, both of the trials failed. First of all, the car turned because of wheels and axles. Second of all, the car didn't move past 4 ft. because of weight and the wheels. We decided to make a whole new design. At school we started making our new design, and finished most of it there. We decided to keep the CDs, straws, scewers, and the egg carton ideas. This time we included corks, instead of erasers, and also added a base for the balloon to sit on. We made a base so that the balloon wouldn't hit the wheels. We finally tested it at school, but it didn't move very far because it had too much mass. On Thursday we all met after school, and made a new platform for the balloon, so we changed a CD case to a small piece of cardboard to make it weigh less. Also, we got rid of the tape, extra glue, and part of the styrofoam egg carton. We finally tested it, and it worked.

Money Spent

We spent $1.99 on balloons.

The 3rd Trial

When we tested the balloon car at first it went really far, but we realized that the ground was uneven. We moved to an area that had more space and less bumps. We taped the 12" balloon so that the air could escape quickly and so that the balloon wouldn't get in the car's way. The car accelerated but hit a chair, so we couldn't tell exactly how far it could go. We could tell that the car was done by how fast it was going.

Rebuild Materials #3

Materials

• CDs for wheels 
• Corks for the axels (in the middle of the CD)
• Straws and Scewers for the axels to spin wheels
• 1.5 by 1.5 inch piece of cardboard for the balloon to sit on
• Egg Carton for the base
• Scewers to hold up the platform for the balloon to sit on
• Tape to hold the balloon down
• Hot glue to hold everything together