Test Day

Our trebuchet that we made was not as successful as we thought it would be. When we tried to launch the tennis ball our weight holder (pail) broke and so we didn't get the ball launched at all. We had to make a lot of changes to our trebuchet. We had to make our throwing arm longer and we had to create a releasing mechanism. As for our pail, we replaced it with a heavy duty rubber pail that had a steel handle. This pail could be attached to the throwing arm with wire. This pail was able to hold all the weights we needed.
A new pouch was also designed.

Cardboard Trebruchet

While making our cardboard trebuchet we had to make sure we had a secure base that could hold everything together and be able to withstand the mass of the weights. We also had to make sure that our swinging arm would release the marble at a 45 degree angle. If anything is launched at 45 degrees it will most likely go the farthest because of its horizontal velocity being somewhat great and its vertical velocity being somewhere between high and low.
When we were trying to make our marble go the farthest we had to add more weight. In order for our trebuchet to launch our marble as far as it could we adjusted our angle and used 43 washers as weights. This allowed our marble to be launched approximately 5 meters.
When we were doing the accuracy test we used 30 washers. Our marble landed in different spots close to where it was supposed to land. This test proved that our cardboard trebuchet was not very accurate.
Some environmental factors that could affect a cardboard trebuchet are;
- The glue could wear away resulting in the whole trebuchet falling apart
- If the trebuchet gets wet it will not be able to perform at its best because the cardboard will be weaker
  

Egg Drop Challenge

During competition day our container was able to keep our egg from breaking. We dropped the container with our egg in it from 5 meters. Our container had a mass of 76.1g and was withing the size limit of 25x25cm. Our egg had a mass of 57.2g and the bag inside the container had a mass of 2.7g. Our drop time was 1.29 seconds. With all of these results we ended up with an egg score of 147.05. This score was the highest score in the class.

I think the easy access was the most restriction to building the containers because that part of the container was the weakest area. Our container had a lid and it was difficult to keep everything packed together under it. We also had to make sure that we didn't pack everything to tight and crack our egg when we put the lid back on.

I think that the most effective part of our container was the sting we had attached to the beg and the lid. Without this sting keeping our egg suspended, our egg would have moved to the bottom of our container and most likely would has broke from the impact. The string kept it centered and didn't allow it to touch the bottom of the container. The least effective part of our container was the very top. If our container landed on its top the egg would have slid to the lid and broke because the string would have had some slack in it for the egg to move. If it landed the right way the sting was tight so the egg couldn't move.

If I was to add two eggs to our container I would make two sections for the eggs to sit in. One on the bottom and one on the top. I would have put layers of paper towel on the bottom then added the egg. Then i would add more paper towel and a small piece of cardboard. After that I would add more paper towel and the second egg on top. More paper towel would be added and lastly the lid. I wouldn't use the string this time.

This is what the inside of our container looked like.

                           

Egg Drop Testing Day

Yesterday our class was able to test our containers to see how well they could keep the egg inside from cracking.
First our group started at one meter. We measured out where one meter was and dropped the container with the egg in it. The egg didn't break so we put everything back together and moved up to two meters.
At Two meters we dropped the container with the egg in it and the egg still didn't break. We then put the egg back into the container and moved up to three meters. At three meters we dropped the container and it ended up rolling down some stairs. We thought that the egg would be broken for sure but when we checked it the egg was still not broken. At four meters we dropped the container and this time the egg did break. We did some adjustments to our container by adding more tissue to the bottom of the container. We then dropped the container again from four meters and the egg didn't break. At five meters we dropped the container and our egg got a very small crack but didn't break open completely. So far I think that our container has been successful at the three or four meter range.

This is Jasa and I putting the container together.

 This is one of our videos of the container being dropped and it rolling down the stairs.

Spaghetti Bridge

1. The process of building this bridge that I found most rewarding was learning how to build and design a bridge that can hold a large amount of weight compared to its size. I learned how to incorporate different styles of brindges into one bridge.

2. The specific strengths of our bridge were the two main beams on the bottom along with the crossed beams that lead from the top to the bottom outside corners. I think all the small supports also helped out with keeping the bridge from falling apart.

3. If I was to change anything with our bridge I would add more small beams at the bottom of the bridge. I would also make the top supports shorter. The extra small beams at the bottom would add more support at the bottom and would help it from snapping at the bottom. If it had shorter supports it might be able to hold more because there wouldn't as much stress on the supports.

4. Before you start making your bridge look up different designs and try to figure out where the pressure points will be on your bridge so you can strengthen the areas with the most pressure.

Our Group

The bridge we made.

Our bridge was the strongest bridge. It held 14000g.

Final mousetrap vehicle post

Things that went well:Our mousetrap vehicle was very consistent. The vehicle was also successful in the drag race. Our vehicle ended up being the second fastest car out of six vehicles. The car was very easy to put together and reassemble. If we needed to we could take our wheels off of its axels and adjust the car easier. At the starting line our car had a smooth start. It didnt spin out or stall when the trap was set off.

Future Recommendations: If you want your vehicle to keep rolling far make sure that your axels have room to rotate. You dont want the axels or the wheels to rub on the chassis and create more friciton because it will slow your vehicle down. When you are designing your vehicle try to have bigger wheels at the back and smaller wheels at the front so that there is less area to cover. The bigger the wheels the less the axels had to rotate. If your wheels are to small the axels will have to rotate more to get a far distance. Try to make your chassis as light as possible so that there isnt large mass that has to be moved. Make sure that you have a sturdy vehicle that wont break when the trap snaps.

Last Mousetrap Vehicle Post

Our group with our car. Photo by Josh

A top view of our car at the starting line. Photo by Josh.

Our mousetrap vehicle went 7.19 meters. That was the farthest it went out of all three of its runs. In the drag race our vehicle ended up in second. 

If i wanted to modify our vehicle I would change how we attached the axles. The axles looked like they were bent and I noticed that when the wheels moved the axles would rub on the plastic tubing. I would add some type of lubricant to help the wheels rotate on the axle easier. 

If I wanted to build a completely new car I would build a car with only two wheels so that It would not have as much friction as a car would with four or three wheels. 

To make our vehicle work better to go a little bit farther I should have paid more attention to the axles.