Trebuchet Challenge Recommendations

During the process of building our trebuchet a lot of things actually went wrong for me and my partner. During test day our trebuchet threw our tennis ball nowhere. It would throw it straight down or the tennis ball would stay in the pouch. After a few frustrating days we finally got it to work when it had to. The things that went well for us would be that our trebuchet performed when it needed to.

Some tips for future students would be to use a denim material for your pouch not a cloth material because the cloth will wrap around the tennis ball and not let it go. Also use strong wood because you don't want your trebuchet falling apart.

Trebuchet Challenge

In the accuracy part of the challenge our trebuchet performed extremely well. For our first throw we put most of our weights on and the ball hurled past the target and to the left of it. For our second throw we took some weight off and aimed it in the same position, our result was the correct distance but a bit to the left again. For our third throw we kept the same weight on the trebuchet but aimed it to the right. Our result was just about perfect as the ball landed 48.5cm away from the middle of the target.

Our trebuchet in action during accuracy competition

If I wanted to design our trebuchet differently I would change it to make the throwing arm lighter. I feel if the throwing arm is lighter it would get more speed and therefore throwing the ball farther.

If I were to make a whole new trebuchet I would make it out of steel because steel is more reliable and stronger than wood. I would also make it so that the throwing arm would be longer and lighter. 

Cardboard Trebuchet Challenge

Here is a video of our trebuchet in action.

Cardboard Trebuchet Challenge

In physics we built a mini cardboard trebuchet to give us an idea on how to build the big wooden trebuchets. To make our cardboard trebuchet work at its best we had to use our physics knowledge. We had to use our balancing concepts (with the weights) and our trajectory concepts (make sure the trebuchet launched at 45 degrees), by doing these concepts we got our trebuchet to perform at its best.

Some environmental factors are that the glue may not have settled correctly and made the trebuchet unstable or the string may have weakened through the gluing process.

Some performance factors are the launch angle of the trebuchet and the amount of weights we put on for the counterweight.

Egg Drop Competition Day

Egg after the drop

I think that the parachute restriction was most limiting because our container dropped too fast and hit the ground too hard. I feel that if we had a parachute attached to the container I feel our egg would not have broken. The most effective part of our container would have to be the bubblewrap. I think this was the most effective because we used a lot of it and it cushioned the egg very well. I think the least effective part was the milk carton. I think this because it was hard and it didn't cushion the egg very well when it made impact with the ground. If we had to add a second egg to our container we would have to carefully wrap each egg in tissue paper and then divide them with bubblewrap. I feel this idea would safely support two eggs.

Container mass- 57.2 grams
Time of fall- 0.75 seconds
Distance of fall- 5 meters
Condition of egg- Broken
Points earned- 0

Egg Drop Test Day

We tested our egg drop container the other day to see if it would work or if it would fail. We decided to start dropping the container from about 3 meters and it survived. The next drop was from 4 meters and the egg decided to break. We went back to the classroom and discovered that we needed more padding on the outside of the container, not on the inside. We put bubblewrap on the outside of the container and added just a bit more padding on the inside and went and tested our container out again. We started off at 3 meters and survived so we went straight to 5 meters. At 5 meters it hit the floor and bounced a couple times and to our surprise the egg survived. We dropped it a couple more times and it survived each drop. Our container is 57.2 grams.

Our egg drop container

Spaghetti Bridge Reflection

1.) The process that I found most rewarding was when we started putting weights on our bridge. This was cool because all our hard work paid off because it held more weight then expected.
2.) The specific strength of our bridge was the middle support. It was good because we put the most spaghetti in the middle.
3) Some changes that I would've made to our original design to make it stronger would be to flatten out the spaghetti while it was drying. You do this by putting a text book on the spaghetti while it's drying.
4.) Some tips I would give to future spaghetti bridge designers would be to plan out what they're glueing and then glue everything at one time because it takes a long time for it to dry. I would also tell them to put a text book on the spaghetti while it dries to keep it flat.

Picture of our group. Jon, Jenn, Cam. Photo taken by Mr. Bertram