What I learned at the Expo

 

I saw a sand castle station at the expo. The lady who was doing this experiment found out how the sand castles were formed. The sand forms a sand castle by absorbing the water and forms into a mold, but if you add soap to the sand and water, the soap will break the water’s surface tension, which makes the sand not absorb the water as well. Then we tried to make a sand castle with the water to see if it didn’t work, and it fell apart. Then the lady asked us to make a ball to see if it would form easier that way, but when my group set them down, they fell apart and went down the sides of the table.

Then we saw college students who made a project at the end of the semester instead of having a test. They did the project on medical things. The girl who was there explained how doctors sometimes have the problem of not knowing when to stop when they are drilling into a bone, and sometimes they accidently go too far and go into muscle or tissue, so she made a drill, that had a stopper on the end so the drill could only go through the bone not any farther, because they had a medal tube in the place where the drill bit was supposed to go, and they inserted the drill bit, which was smaller than the tube, and explained how it worked. It would stop at a certain point because at the end of the drill bit, it was bigger than the medal tube, so it would stop. They did this on a bone that they made and it stopped once it was threw. The college student built it.          Molly