Charge

Purpose:  In this experiment, we observe how charges behave when they are near each other. We also prove that there are two kinds of charge, one positive and one negative.

A Charged Balloon

We start off by rubbing a balloon. This balloon was rubbed against Professor Mason's hair and stuck to the glass that the balloon was next to. This is because the balloon lost some electrons during the rubbing process and became positively charged. When held next to the glass, the electrons in the glass gathered toward the positively charged balloon, causing an attraction.

Charged Tape

We take another look at charge when we charge tape by quickly separating tape that is taped on each other. The two pieces of tape stick to each other because on tape becomes positively charge by losing electron to the other tape. This make the other tape negatively charged. This shows that positive and negative charges attract.

We then ask ourselves, " how can we show that there are actually two charges in play?" Well, we do the same thing shown in the previous picture but with a second set of tape as well, giving us four pieces of tape. when we charge all of these pieces of tape in the same manner, some of the tapes repel, and some attract, showing that there are pieces of tape that gain the same charge and that there are two kinds of charge.

As part of the observation of the two tapes, we had to come up with explanations for why the tape behaved the way it did. This is what we came up with.

Charge Using Newtons Laws

In this problem, we went oldschool as we applied Newtons Laws to find the electrical force done on the charged ball.

Using the force we found using Newton's Laws, we found a relationship between Force and R. We can see that the force falls at one over R squared.

Same Charges Don't Attract

We take a closer look at the behavior of two charges by mapping out their positions. The red dots track the motion a man holding a charged ball on a stick and the green dots track the motion of a charged ball that hangs on a string.

Using the same equation for electrical force derived using Newton's Laws, we were able to get Logger Pro to calculate the force on the ball. We, then, graphed a force versus distance graph and, again, it shows that the force is inversely proportional to the separation distance of the two same charge objects.

Here is some of the numerical data obtained.



This picture contains a detailed analysis of our fit equation for the force of the two charged balls on Logger Pro. The fit equation was raised to the power of negative 2 and this is consistent with the equation for force of an electric charge.

This picture contains some more analysis. Number 4 shows where some uncertainty lies in the experiment.

We take a look at two opposite charge balls and these charges have the same charge in magnitude. We see that the force of the charges follow Newton's third law.

Franklin Motor

We start off by see how the paper would react to vandegraff generator. Most of us were able to guess that the paper would move in the way shown in the picture.



The paper from the previous picture shows us that it is resisting gravitational pull, so, we calculated the ratio between the force of gravity and the force of electric charge. Electric charge is roughly ten raised to the power of 40, which shows that it is much strong than gravity.

When we set up the Franklin motor, we see that the top spins clockwise. The charge is dispersed to the ends of the three metals that spin.

Our picture shows our prediction of the direction of the rotation as well as the reaction with the paper. Both of our predictions were true.

Conclusion:  Step by step, we prove that there are two charges at work when we talk about electrical charge. This was proven using tape. We, then, used Newton's Laws to see the force of electric charge and plugged this formula in Logger Pro to find the behavior of force versus separation distance. The graph showed some inverse proportionality, which we fitted, and we found the force was inversely proportional to separation distance squared. We talked about the application of Newton's third law and went into different examples of charging objects. The behavior proved to be a little predictable.