Reflection and Recommendation

Amidst all our challenges, a lot of things went well for my team with our trebuchet. We achieved good distance (av. 30 M) and outstanding accuracy (within 0.50 M). Our trebuchet was well built (solid and steady) and held for as many trials as we needed (for the most part anyway). We had ample materials and resources available to us for this project, and we worked well as a group.

For future groups, I recommend using a fairly heavy material for the frame (solid wood or metal) to provide strong solidarity and stability. Use a narrow and tall design with a long throwing arm to achieve good distance. Use a strong enough metal for an axle so it doesn't bend or break with a heavy counterweight (ours was 120 pounds). Finally, use counterweights that are easily massed and changed to allow for quick adjustments, and use a simple angle of release mechanism that is easily and quickly adjusted. Make sure a safe release mechanism is installed.

Post-Competition Reflection

Our trebuchet had outstanding accuracy performance! We won first place, coming withing 0.50 meters 0f the center of the target.
If I were to modify our current trebuchet, I would likely make it a little sturdier so it wouldn't bounce so much when fired, and I would modify the counterweights so they are easier to add and remove.
If I built a whole new trebuchet, I would make it narrower and taller to allow for a longer throwing arm, thus hopefully achieving greater distance. I would also install a better angle of release mechanism that is easier to adjust and holds its angle better.
On our current trebuchet, I would tweak our angle of release and security of our throwing arm. This would hopefully achieve greater distance and prevent the arm from moving from side to side, allowing for better accuracy.

Final Adjustments

The accuracy competition is looming close. Our average in the distance competition was 30.41 meters. This may just be a little too far for the accuracy test. To achieve better accuracy, we have agreed to adjust our counterweight mass to reduce the speed of projection. We don't intend to adjust our angle of release unless absolutely necessary, as I think we have a good angle already set.

Competition Day!

Awesome performance! Although not as good as we had hoped. We calculated our theoretical range to be a whopping 813 meters! Now, compared to our actual average of 30.41 meters...

Five reasons we believe our trebuchet did not achieve our theoretical range are:
1) 813 meters seems a little ridiculous
2) Our angle of release probably wasn't exactly perfect
3) Air resistance on the throwing arm and counterweight
4) The design of the trebuchet should have been narrower and taller, as opposed to wider and shorter, allowing for a longer throwing arm
5) Gravity on the tennis ball when it flew

Trebuchet Test Day!

On test day, or trebuchet averaged a distance of about 20 meters. We believe this was partially because the wind was not in our favor for the day. For competition day, we are going to install a stronger axle (namely one that won't bend or break), possibly a better sling, and a different counterweight (one that is easier to work with and more easily massed). We are thinking about using barbell weights. We are also going to fasten our track more securely to our frame for better guidance and possibly find a new angle-of-release mechanism. Finally, we need a new trigger mechanism, and are leaning toward door latches for this.

Yesterday we finished off our cardboard trebuchet. We were not able to achieve great distance. I think this was due partially to the weight of the projectile and difficulty in setting a correct angle of release. The precision was really good. A steady angle of release and counterweight mass was to thank for this. As we construct our full-size trebuchet, we will need to carefully calibrate our angle of release to achieve maximum distance and accuracy. We will also need to make sure we have appropriate counterweight masses. In regards to environmental factors, only gravity played a part with the cardboard trebuchet, as we tested it indoors. We hope that wind and weather are in our favour when we test the full-size model next week!

Today we began research for our Medical Physics challenge project report. We chose Magnetic Resonance Imaging (MRI) for our topic. We decided that Jordan will be responsible for a description and background information on our topic, and our reason for choosing it. I (Jonathan) will be responsible for the history of our topic, as well as a description of how this technology works. Carmen will look into future applications of the technology, as well as other interesting facts about it.

Egg drop results- Feb. 24

Mass of container = 143.2 g

Dimensions = 20 cm/13 cm/7.5 cm

Time of fall = 0.87 seconds

Fall distance = 5 meters

Condition of egg = unharmed!

Total score = 139.7

When designing our container, we felt that the factor that would limit our container's performance the most would be its shape. We thought it would be an issue if the container landed on its narrow edge, as it was difficult to place padding for this spot, and the egg would've had a stronger chance of falling out of its cradle within the box.

I think the most effective part of our design was the cradle for the egg. The box we used happened to have a small cardboard cradle-type contraption inside it. The egg fit perfectly into it. This helped to stop the egg from moving around in the container when we dropped it or upon impact, thus reducing the chance of the egg shattering.

If I were to do this project again, I would likely use a box with more equal dimensions. I think this could reduce the need to drop it on the correct side of the box.

In order to carry two raw eggs, we like would've had to install another cradle in order to support the second egg, and possibly even used a bigger box, as the one we used was not very big.

Feb. 17 - Egg Drop Prototype

For our project, we are using a cell phone box with bubble wrap and a home made dish cloth for padding. There is a small cardboard cradle inside the box in which the egg fits perfectly, preventing it from moving around in the box. We dropped it from about 7 meters, and to our surprise, the egg was unharmed every time. We agreed that we should implement more padding (considering Murphy's Law) and decorate the box for some originality.

Thursday

Today we implemented some Internet safety features onto our blogs, including spam filters. We also added a Clustrmap, which allows us to see who views our blog. We ended off by commenting on likes and potential improvements of other peoples' blogs.

Day 2

Today we experimented further with backgrounds and designs. We added gadgets and looked at privacy options. We finished off by following everyone elses' blogs and posting to summarize what we did today

Feb 8, 2011

Today I created this blog for Physics