Diary Entry #4: Farewell & Lasting Thoughts

Well guys, we had a good run. It has been really fun blogging about the creation, struggles, and successes of our mousetrap car. This is our last diary entry before we sign off for good.

Dear Diary,

To be honest, we think the most exciting part of creating our mousetrap car was everything. It was a lot of fun to experiment. First, we had a pretty good model and then it fell apart. After that we created a new model that was 10 times more successful. Going through that whole process was a struggle but we found it enjoyable.

When it comes to our group, we think we all meshed together pretty well. We had all worked with each other at least once so we already knew each other. Working together was actually pretty fun. We always tried to make light of all of our "bad situations", staying positive and optimistic. Creating the blog was pretty funny because we tried to make it really good and took it really seriously. We learned that when it comes to collaboration, splitting the work up evenly is good because it makes sure the amount of work everyone is doing is equal. Also, making sure that there is no type of negativity in the group is good.

We think we did a really good job on our car. Obviously, there are some things that we would change about it like the aesthetic appearance, the body of the car, etc. but just minor things.

THANKS TO EVERYONE WHO READ THE MOUSETRAP FILES! WE'LL PROBABLY START OUR OWN PERSONAL BLOGS SO LOOK OUT FOR THAT!  #MOUSETRAPTEAM2015 #MASONTARAHKALINA

Till next time!

Mason, Tarah, and Kalina

Energy Story: Our Mousetrap Car = Global Warming at its Finest

THE SUN

Soil

Plant

Animal

Food

People

Setting the Mousetrap Car

Acceleration of Mousetrap Car

Friction (Thermal Energy)

Heat

All of the energy on Earth we receive is from the Sun. From there, energy is passed on through different forms but is never destroyed. From the sun, energy is transferred to the soil, then from the soil to the plants, then from the plants to the animals, then from the animals to our food, and from our food to us. The energy we get is transferred to us so we can set the mousetrap, and then the energy is transferred to the mousetrap by accelerating, and then the energy is transferred to friction through the wheels, which is then transferred to thermal energy, and then becomes heat. The heat radiates off of the Earth and the cycle continues.

Physics Analysis

After doing calculations, we were able to find our mousetrap car's potential and kinetic energy.

Kinetic Energy: 1/2(mass)(velocity)^2
                            1/2(.192)(1.49)^2
                            =.2131 J
Potential Energy: (avg. force)(distance of string)
                          (2) (.055 * 3.14)
                          =.3454 J

These calculations make sense because while the kinetic energy is less than the potential energy of the mousetrap spring, friction in the wheels and body of the car will cause the thermal energy to rise and the kinetic energy to decrease. The length of the lever arm was multiplied by the average force to find our potential energy which makes sense since it is half of the length of the mousetrap itself. The efficiency of our mousetrap car is 61.7%.

Because this mousetrap spring is not that strong, it makes sense that both the Kinetic and Potential Energy are low values. The Total Energy never changes, but instead converts between Kinetic, Potential, and Thermal Energy (created by friction).

Our greatest problem dealing with friction was between the axles and body of the mousetrap car. The axles turning would create friction against the cardboard body and convert some of the spring's Potential Energy into Thermal, instead of Kinetic Energy that would make the car accelerate.

Phase 4: The Final Trial

We performed three trials in class today, and discovered that our mousetrap car's maximum velocity was 2.545 m/s.

This is the video that captured our fastest trial, Trial #2.

After analyzing the footage in Logger Pro, we found the maximum velocity of 2.545 m/s.

Final Thoughts on our Final Trial

With our previous car we only reached about half of the velocity that we reached today with our new car and even when we remade our car, it didn't initially have the results that were received today. With tweaks to our car, we felt as if we found ways to maximize our kinetic energy. We tried new things such as a different way of setting up our project and that turned out to be very beneficial. Although we learned what to avoid with our old car we wish we had more time with the new car because we feel if we had worked on our second car with the complete duration of the time allotted to us, we could have even further maximized our kinetic energy, but we still are proud of the car we put together.

Starting From Scratch

After modifying our mousetrap car today in class, we found that the complications were the eye hooks, the string, and the cardboard body. The eye hooks were too loose around the axles, and were not strongly attached to the body, so when we tried to run a trial the eye hook turned and the weak body bent in such a way that the string could not unwind and the axle could not turn. The string became tangled around the axle and around the mousetrap itself, making it so that the potential energy of the mousetrap spring could not be transferred into making the car accelerate. The cardboard body wasn't sturdy enough to support the eye hooks and the mousetrap, and bent when the wheels and axles turned.

When our modifications failed, we decided to construct a whole new mousetrap car, because the body and its connection to the axles all had to be replaced.

Our new prototype looks like this:

The body is a tissue box, and the wooden dowels (the axles) are going through the body, which proved to be a sturdier connection than with the eye hooks. The CD wheels are attached by corks to the axels. We remade the wheels to be wrapped in duct tape to provide traction. The body is held in place by tape wrapped round the dowel on the outside of the body. The mousetrap "engine" is hot-glued to the base of the tissue box, and a shorter piece of string is tied to the snapper arm and the back axle.

We only had time to run one trial with our new prototype, and it managed to accelerate at a decent velocity. This is a good start, but we still need to keep improving this model!

Diary Entry #3: Successes and Failures

Dear Diary,

In class on Tuesday, we ran a few more trials with our car and made various modifications.

The most successful thing was that the car was able to accelerate at a decent velocity in the several trials that we ran. We kept it in mind that we had to wind the string around the back axle without getting it tangled making sure it unwinds smoothly and to pull the mousetrap's snapper arm all the way back making sure that the spring has the most potential energy so in turn the car has the greatest kinetic energy during the run. We were going to capture the trial in a video, and then analyze the data to find its velocity, but ran into some complications.

The least successful thing was these complications: the mousetrap breaking off of the body, the shifting movement of the body on the axles, and the tangling of the string on the back axle. To tackle these problems, we first decided we should unwind and shorten the length of the string to avoid the tangling of it when we set the car. To address the shifting of the body on the axles, we wrapped duct tape around the dowels on the outside of the eye hooks, so that the body can no longer slide from side to side on the axles. This was wasting some of the energy that could go into making the car accelerate. Next, we will reattach the mousetrap to the body with a stronger adhesive, or use stronger cardboard or other material for the body itself.

We have a few modifications to address, but we feel that we are off to a great start!

Phase 3: Prototype

We completed our first trial yesterday and it went pretty well. Below is the video of our car being launched.

Obviously there is a bunch of stuff we would like to improve with our car, mainly the efficiency of the string, but we believe this is a good start.