Wednesday, December 3, 2014

Barbie Project (Blog #3)

My heart was beating fast, I was nervous.Today, we had a jump competition, and by saying that, we had to throw our barbie from any location that Mr.Oksness had chosen. One of the most important aspect in this project was that we had to find a pattern or some kind of equation in order to figure out how many rubber bands we would need approximately. Thus, we also always had to keep in mind that we couldn’t let her hit the ground, but at the same time, to try to be as close as possible. The reason I was very nervous about it was because of the fact that I had missed the last class, which was very important for our group. Due to that, I was in a hurry to talk to them during class, and we immediately had to come up with a pattern and solution so that we could have a success in the bungee jump.
We started calculating, observing our data, and after much difficulty, we kind of noticed a small method! We found out that from 100cm (5 rubber bands) to 200cm (13 rubber bands) , we needed 6 more rubber bands than before. Then, for 300 (25cm), it increased 12 more. Due to that, for the 4m we concluded that we would need about 49 (25 + 24). However, I was confused at that time, and couldn’t think properly. Because of this, I only thought about how much rubber bands were increasing. Additionally, since it was 24 rubber bands increased, I just added about 6 more to get the 83cm. (I don’t get how my mind worked that time). Anyway, after some calculations, we ended up using about 49 rubber bands for the competition, which I strongly disagreed with them upon. I kept convincing them that we needed to use about 30. The time came, and we were given the place to start our rounds. We just ended up using 49 rubber bands in total. Quite as I had expected, it hit the ground, and not to forget to mention, our team was “disqualified” in the first round since we kept pulling the rubber band in, in each trials. I was very confused, and felt very guilty of doing so. Not only that, but I went by myself, and tested out how it would work with 30 rubber bands, and surprisingly it worked pretty well. Yet, it wasn’t too close to the ground either, which I actually felt was very safe.
After learning about it, for the next trial, which was kind of like a “re-take”, we gladly didn’t make the same mistake. Additionally, for this second game, we used 60 rubber bands, since first, the time I tried by myself for 4m and 83cm, I used about 30 rubber bands, so for the 8 meters, I believed that about twice would work well. I just had this imagination that if I doubled it, it would touch the ground just like the first try. Secondly, we decided that we had to take off the height of the doll from the total height of the drop, since that was the height we wanted her to be apart from the ground. Then, after taking off her height from the height, we measured how much the rubber band stretched, which we had done in the first class, and that was about 12cm. Due to that, we made an equation of (Height - 30)/12 . This calculation made up to about 64, due to that, we took out 2cm just to make sure she wouldn’t hit it, but because we were too afraid, we just took about another 2 more (basically 4) just for safety. That’s how we got to using 60 rubber bands for the second trial, and it worked out beautifully. Unlike what I had imagined, it was actually extremely close to the ground (about 1-2 cm off the ground)! I was astonished, and felt so glad that we had taken out the 4 rubber bands.

Moving on, if I were to do this again, I would have tried to figure out the equation earlier. After  thinking calmly, we noticed that the equation The (Height of the whole thing - Height of the Barbie) ÷ The amount of how much the rubber band stretches would work the best. This equation always gets closer to the actual number now that I’m trying it alone. I’m very pleased that we were able to find out the equation, and I’m so thankful that we took some rubber bands out. Phew~

Height (cm)
Number of rubber bands used
40 (failed)
60 (success)

Overall, even though not everything was a favorable outcome for our group, I really enjoyed working with different people since I haven’t really done something like this before. I thought that it was great how we used something realistic - connected to life, instead of doing something random. Not to forget, I actually did kind of feel like an engineer trying to figure out a difficult, real-life connected, math problem. Furthermore, I’ve improved on my communicating skills and teamwork from this project. After all, from our mistakes we’ve made, we also learned from it which is one of the most important aspect in this project in my opinion.

(Our "re-take" trial!)

(One last glance of our beautiful barbie)

Barbie Project (Blog #2)

To start off, I missed the class due to the Orchestra combined rehearsal, however, according to my group, they were able to test our theory. Firstly, they had discussed about how if you double the height, we also have to double the amount of rubber bands and an extra rubber band to weigh in the gravitational pull. I wasn’t quite sure if the gravitational pull would work, or count since gravity was always the same in pulling (9.8m/s2) Anyway, to check if our equation we made in the last class was precise, and made sense, they tried it with 300cm, and also doubled the amount of rubber bands plus an extra one which equaled 22 rubber bands. Sadly, this didn’t work out too well. However, they noticed that they had been using a different kind of rubber band, so after they got the “original” one, and tried adding three more rubber bands. Luckily it worked, and so it was concluded that we needed 25 rubber bands for 300cm.
Moving on, they also tried it in a smaller height of 250 cm and removed 7 rubber bands from the 22. When doing this, they noticed that the barbie could go even further, due to that, they added 2 more rubber bands. Unexpectedly, the barbie hit the floor, and without further adieu, they removed one rubber band again, and luckily, it didn’t hit the ground. Lastly, they were able to conclude that for 250cm, they had to use 16 rubber bands. After that, they tried 200cm, since it was between 250 cm and 150cm, due to that, they also thought of getting 11-16 rubber bands. Additionally, when using 13 rubber bands, it just worked perfectly.

Height (cm)
Number of rubber bands used

As we went up every 50 cm we started to see a tiny pattern. For example when we increased from 150 to 200 cm we needed two more rubber bands than the previous one. Then when we increased from 200 to 250 we had to go up 3 rubber bands. Therefore, we thought the pattern was every 50 cm you had to add one more rubber band to the amount you added last time. But then we saw that when we went from 250 to 300cm, the changes was up to 9 rubber bands. Because of this, we couldn’t figure out the pattern and had difficulty figuring out what was wrong. The three rubber bands had tripled in amount as if the pattern was to multiply the previous amount of rubber bands by itself.
Personally, I think that we have some chances in the jump even though we don’t have an exact pattern distinguished. I hope we have a successful competition, where we’ll get it right, and not let the barbie suffer. Even though we are kind of ready, we will do a final test before the actual jump and for the finale, we will consider everything we have seen in the trial, such as patterns and other calculations. I am very excited to see what will happens, yet I am worried concerned that we will make the same mistake and lose the game. Thus, I do feel that there is an equation, just that I’m not thinking too hard to find it. I’ll try to see what is making this project a big problem for us.

(Done from the stairs) 

(Done from the classroom)