Egg Drop- part 2

Hi, so guess what??? Our egg drop device was a SUCCESS! Keana and I (aka the Peruvian Eskimos) had a great day on Wednesday. Watch the video above for more details. Keana dropped it over the side of 'Akahi (about 3 1/2 stories tall) and I video'd its' fall. We did have to make a minor change, however: instead of stuffing the box with cotton, we used crumpled up (UNUSED) toilet paper. It did not matter— the device still did its job to our satisfaction. I was so happy not to hear a sickening thud and the squelch of a broken egg coming from our device, like it did to some other groups. However, we did have to do it again because the first time we dropped our device, it kind of hit a bush. That means that our egg survived TWICE :). All of the groups in our class had great ideas for egg drop devices: one group had a stack of sponges that encased the egg and was secured by rubber bands, another had aerodynamic design that would allow the egg to land safely, and yet another was a simple box filled with lots and lots of packing peanuts and filler. No two groups had the same design, so it was interesting to see how most of them worked. There was actually nothing I would have changed about our design... it was successful, so why change what already works?

Egg Drops, Impulse, Momenta, and other delicious topics

So this week we worked on creating a device that could contain an egg and deposit it safely (NO CRACKS) when dropped from 3 1/2 stories ('Akahi). We'll be testing these on Wednesday. So, I spent my period 4 with Keana making this device... how did we do ours? We built a 20cm x 15cm x 15cm box from styrofoam board in the SPC. In order to increase contact time and hopefully give the egg cushioning, we plan to slide the egg in a nylon stocking and knot the other end so it does not move around. Then we will fill the rest of the box with cotton, then tape the box shut and drop it over the edge. Although it would be wise to build a crushable box (to prevent elastic collision), we did not because we wanted the box to be stable in order to support our egg. We figured the cushioning we'd provide would suffice. Hopefully it works... tune in next week so I can tell you if it worked or not!

Learning Impulse and Momentum Is A Piece of Cake

Impulse can be defined as the 'change in momentum', or the average force multiplied by change in time. Impulse is a vector, just like momentum, and uses the same units (kg m/s). Let's work on finding the impulse in this problem. A 0.015 kg cake (like the one I have shown above) is thrown into the wall with a speed of 100 m/s. If the cake miraculously doesn't crumble and instead bounces back with a speed of 80 m/s, what is the impulse?

Well, first, we'd find the momentum. P=mv is P=.015 kg *100 m/s = 1.5 kg m/s. Then, P= .015 kg * 80 m/s = 1.2 kg m/s. When those two momenta are added together, you get 2.7 kg m/s, which is the change in momentum, or IMPULSE. And that, my friend, is the easiest way to have your cake and eat it, too. Although I'm not too sure why you'd throw that cake to begin with...

Momentum (or what I think it might be)

This week we will be talking about linear momentum and collisions. So here is what I think momentum is, straight off the bat, before we get into the real deal. I think momentum is the force of an object in motion— like a pendulum or that Chinese junk ship that Johnny Depp overturned in the third Pirates of the Caribbean movie. Momentum seems like such a loaded word: I am not sure what the most accurate definition of it would be, but it seems to be that momentum would have to do with both magnitude and direction. An example of momentum could be the force (?) behind the ball in a golf tournament, or the motion in a washing machine, right? I'm not too sure... this is just what I think so far, but I'm pretty sure momentum has to do with that sort of thing. We'll figure that out this week.

Maybe my sister is in momentum...? If she is moving with magnitude and direction...