3-10+husted

3-10

Physics Journal:

     Today in class we started off the seventh period class with a brief demonstration by Mr. Manning. In this demonstration we learned about the centripetal force in a little set up built by Mr. Manning. He cleverly attached a clear plastic CD case to four pieces of string, one on each corner, and they were all tied together at the top. Then, he placed a plastic cup full of water on the top of the case and held the device by the string. He swung the string attached to the case around in full, 360 degree circles, and to our amazement, the cup did not fall, and the water never spilled out from the cup. He explained this experiment with centripetal force. The axis, Mr. Manning, was pulling force opposite to the force that the cup wanted to go. This way, the cup always was turning tangent to the circle and therefore stayed on the CD case. The tension of the string also helped along with the centripetal force on the cup by keeping it taut and not letting any slack for the cup to change direction. After this mind blowing experiment, we worked on our lab on swinging children around in circles and testing the radius, the speed, the time, and graphing our results on a program, Graphical Analysis. We worked on these graphs, the rest of the class period, testing each variable to tweak the data by squaring them. Two, out of the three graphs could be straightened out by squaring them out, but one remained curved, not being changed by either variable being squared.

The cup never spills!