Sunday, March 28, 2010

Science Saturday - bridges

The activity yesterday at Science Saturday was popsicle stick bridges. First there was a discussion about bridges and how they are built. Then the kids were instructed to design their own bridge. It had to span at least 14 inches and could use at most 45 sticks. Parker and I started designing and came up with a "teepee" bridge design. The top view photo below may make the "teepee" idea a bit clearer. The popsicle sticks were hot glued together and then the joints were reinforced by drilling a small hole in the joint, adding a piece of broken paper clip, and adding more glue to hold the "metal pin" in place.

After the bridges were all constructed, they were tested. Two bridges were set up on stools 14 inches apart and weights were suspended from them. They kept adding weight until one of the bridges broke. Then another bridge was brought up, weight was added to get it up to the same weight as the first one, then the weight adding continued. Parker's bridge never broke! After all the other bridges broke they were going to try to break Parker's, but it slipped off the stools before it broke. So he got to bring it home. He didn't want to break his bridge anyway. Once he found out that they were going to try to break it, he didn't really want to make it, but he didn't want to leave either. I said he had to make a bridge or go home, so we made a bridge. And it all worked out for him.

By the way, Parker's bridge was the "last one standing" because triangles are stronger than squares. Most of the other bridges made were square or rectangular.

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