3/3/11!

Recently in science, we've started a new unit involving force.
To learn about force, Kevin had to stand with both of his arms out, with a bowling ball in one hand and a ping pong ball in the other. He obviously needed to work hard to keep the bowling ball level. To do so, he was exerting a positive force on the ball. For the ping pong ball,
he also had to exert a positive force, just not as much. He was not 'doing work' because neither the bowling ball or ping pong ball was displaced, and, since work=force x displacement, there was no work done despite how large the force is.


We then created a definition for force, which is: the interaction between 2 (or more) objects. The objects could be stuff touching it, although not directly, like with the sun, moon, earth, or even a magnet.

To learn more, we continued to study the experiment with Kevin. While Kevin was exerting an upward force, the earth was also exerting a downward force. Since these two forces were equal, the bowling ball stayed in place. If Kevin were the only thing pushing the bowling ball, the ball would simply continue upward.

Today, after reviewing last night's hw, our task was to perform a spring scale experiment. We had to measure something on the spring scale that is a good mass- not so heavy that the scale will break, but not so light that it can not be measured.
My group placed a metal circle on the scale, which measured to be 1N/100g. We created a force diagram. There was an upward arrow to represent the F of spring on mass, and a downward arrow to show the F of earth on mass, and, a circle in the middle to show the mass itself. The mass was pulling the spring scale down, while the spring scale pulled it up. It was unclear to us weather or not the forces were balanced.
Spring Scale

To better understand the concepts we're discussing, trying some of these experiments and recording observations of them could be very beneficial.



KV (#3)