Bridge testing

Well, today was bridge-testing day in Mr. Ambrose's class. All of the students' bridges passed - all held at least the specified two pounds! Most held more. First, we tested Mr. Ambrose's bridge; it started to crack with about 1.5 kg on it (which is a between 3 and 4 pounds). Then, we went through the students' bridges. Some just wanted the test weight on it; others wanted to keep putting on more to see how much it would hold. They seemed to be having fun, even those who hadn't been too enthusiasitic in the beginning. One bridge COULDN'T be destroyed with the weights available - we ran out of weights, and the stack was getting unstable, but the bridge didn't even visibly bend.

After testing the bridges, I put most of them onto the balance to see what their mass was. The heaviest was still under 20 grams in mass. We gathered back together as a class, and I pointed out that by using physics knowledge, they were able to make bridges that would hold many times their own weight, and contrasted that to early bridges, which were made large and massive since the people building them didn't know how to design them to be lighter. It seems like they learned something, and they had fun, so I'd call the project a success.

I did take my camera with, but the batteries died. Fortunately, Mr. Ambrose had his camera and took pictures; as soon as I get them from him, I'll post them on CTOOLS and perhaps put one or two on the blog. I should have them next week.