Eight Day

Spring 2015
19th of March's Class

We start the day learning about electrical charges. Professor Mason got a balloon and rubbed it with fur material, then sticks it to a glass. Once the balloon got into contact with the surface of the glass, it got attached to it for a few seconds.

Then we did a demonstration of electrical charges again with the use of scotch tapes.

This first video shows what happens when we bring together two tapes right after we ripped them from the tape dispenser. As they have a similar charge, they tend to repel each other.

The second video shows what happens when two tapes are placed on top of each other on the bench, and after we separate them, we bring them closer to each other. They hold different charges, and were therefore attracting each other.

The apparatus shown in the image above generates charge by rubbing a belt continuously inside the tube, which was then transferred onto a metal strip that transfers it again into the dome shaped head. This build up of charge generates static electricity.

Volunteers were asked to touch it, and those that did, had their hair rising up slightly. Professor Mason also placed an aluminium bowl on top of it, and it was repelled.

We then did a video analysis on electrostatic force of two metal balls, and created a graph of its electrical forces vs. separation distance. However, we made a mistake when entering the data, hence the graph was inaccurate. Below is the picture of the graph.

1) Yes, we were able to show that the force of electrical interaction between two charges is inversely proportional to the square of the distance between the charges. The shape of the graph shows us that the closer the two charges are to each other, the stronger their interaction.