Lab 1 - Lab 1: Electric Charge and Static Electricity Purpose: The purpose of this PDF

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Lab 1: Electric Charge and Static Electricity

Purpose: The purpose of this lab is to observe the interaction of charged objects, observe the conservation of charge, and experiment with various materials to learn about their triboelectric properties.
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Lab 1: Electric Charge and Static Electricity Purpose: The purpose of this lab is to observe the interaction of charged objects, observe the conservation of charge, and experiment with various materials to learn about their triboelectric properties. Expectations: Our expectations are to see a repulsive force between objects of similar charge and to see an attractive force between objects of opposite charge. We also expect the magnitude of force of two objects to be inversely proportional to the square of the distance between the two objects. Observe the interaction of a single A-tape with various objects: 1. When we brought our hands close to the tape, the tape was attracted to our hands, regardless of the side that was approached. 2. The tape was attracted to balloon, plastic, and metal. 3. As time passes we observed that the tape was still attracted to our hand. Observe the interaction between two tapes: 1. The two tapes repelled each other, indicating that they are of the same charge. 2. Graph for two similarly charged A tapes

Observe the Interaction of A-Tape With Different Charges 1. The hanging A-tape has a weaker interaction with the partially neutralized A-tape. 2. Graph for A tape and a slightly neutral A tape

Create Two Tapes With Opposite Charge 1. The B-tape used was the tape used to create the A-tape. 2. Graph for A tape and B table

3. Our observations from all the previous experiments are consistent with Coulomb’s law and conservation of charge. In all of the cases, the magnitude of force became larger as the distance between the two charged tapes were brought closer together. This is consistent with Coulomb’s law, which states that force is proportional to (1/r^2). Also when one of the two tapes became negatively charged, the other tape was positively charged. This is an example of conservation of charge. Determine the Sign of the Charge on the Tape 1. The A-tape is positively charged because it was attracted to the negatively charged PVC pipe. The B-tape is negatively charged because it was repelled by the negatively charged PVC pipe

2.

Create a charge detector 1. Material 1

Charge

Material 2

Charge

PVC pipe

-

wool

+

PVC pipe

-

balloon

+

balloon

-

Wool

+

balloon

-

acrylic pipe

+

wool

-

acrylic pipe

+

Our series matches the information provided on Wikpedia. The human body is a conductor 1. All matter, regardless of whether it is an insulator or conductor, becomes polarized when it is exposed to a charge. Since A tape is charged negatively and B tape is charged positively, an object that is brought near it becomes polarized, which is a phenomenon called induced polarization. 2. This happens because humid air has a lot of water molecules, and these water molecules are polar. Charged objects lose their charge to these strongly polar molecules. A negatively charged objects will lose its electrons to the slightly positive end of the bent water molecule, or to the hydrogens. A positively charged object will lose its charge to the slightly negative end of the bent water molecule, or the oxygen. 3. Rubbing your fingers on the non-sticky side of the tape causes the A tape to neutralize because the charge from the tape is being transferred to the fingers once they touch. 4. Clothes coming out from a dryer tend to have lots of static electricity because by rubbing against the inside of the dryer, they obtain a negative charge and retain it because there is no moisture within the dryer for the charge to be transferred. The dryer sheet contains positive charges that serve to neutralize the negative charge of the clothes through the transfer of charge. Conclusion

The outcomes of this lab match the expectations we had. The results we obtained were that we saw a repulsive force between objects of similar charge, an attractive force between objects of opposite charge, and the magnitude of force of two objects were inversely proportional to the square of the distance between the two objects. Possible sources of error are the humidity of the room affecting the charges on the tape pieces and also possible handling of the tape with our hands could have caused more neutralization of the tape.

Feedback We liked being able to see the effect of charges and Coulomb’s force. It was also interesting to see how these laws have real life applications, as discussed above in the dryer sheet example....