Electricity Homework

1. An item becomes negatively charged by friction or a loss of electrons. An ion is a atom or molecule that has gained or lost more than one electrons which gives it either a positive or negative chart.
2. An atom is arranged with the center being the nucleus near the center are protons and neutrons. On the sides of the atom are electrons that basically orbit around the center giving it either a positive or negative charge.
3. For something to be polarized there is always a up and a down and an item only works one way. For instance with batteries there is a positive and negative. The battery only gives an item energy if it is connected correctly.
4. An insulator is something that keeps energy in. One way to think of it in today's world is as the insulator that keeps your house warm in the winter by trapping in heat. A conductor is something that transfers energy. For instance a circuit uses copper wire because copper can easily transfer energy.
5. For something to be attracted to one another one force has to be a lot larger than the other to balance out the electrons. For instance if you have a lot of negative electrons a neutral or positively charged item will be attracted to it.
6. A negatively charged balloon attracts neutral pieces of paper because the negative electrons is attracted to all of the positive electrons that the neutral item has.
7. An electric field is the area around a electric charge. The purpose of a positive test charge in an electric field is a negative charge and a positive charge that pulls at surrounding items.
8. Electric potential is measured by the amount of work you put in. For instance if you plug in a hair dryer to the wall it has potential electric energy because the energy is waiting for you to turn on the appliance.

Questions: I don't have any questions currently.

Van de Graff Experience

On March 13th, 2009 we did a Van de Graff activity. The Van de Graff is a machine that stores electrons from a rubber band in a dome. One of the things we used on it was bubbles. We found that the bubbles moved away from the Van de Graff. I believe that they flew away because the electrons stored in the dome is a lot of static energy, and the bubbles are a neutral energy. Therefore the bubbles repelled from the large difference in energy.
Another activity we did was a human chain. One person touched the dome of the machine and several people held hands (one being the person holding hands with the person touching the Van de Graff machine). We found that no one in the human chain got shocked but if someone outside of the chain touched the chain they would be shocked. I believe that this was because the energy of the people in the chain balanced out with the electrons in the dome, and the people got shocked because there body hadn't adjusted to the electron transfer.
Another demonstration we did was one where we placed a napkin on the machine vs. several napkins on the machine. We found that the edges of the single napkin quickly lifted and the napkin flew off. However the stack of napkins did not move, only the edges flew up. I think this was because there were not enough electrons to push away the stack, but the single napkin was lighter and was able to be pushed.
Another example we used to learn was to stick strips of paper to the dome. We found that the pieces of paper stood up and repelled form one another. I believe this occurred because they both had the same amount of electrons so they could not be close to one another.
The last activity we did was to put a handful of Cheerios on top of the dome, and turn on the machine. We found that the Cheerios quickly hopped of the machine in random directions. I think this happened because as the dome filled with electrons the force of the electrons greatly exceeded the amount of electrons in the Cheerios, causing them to repel.
When is a atom a positive or negative based on the amount of electrons an atom has?

Electricity Activity 3-12-09

In physics/math class we did three different activity's to learn about electricity. The first activity was to rub a balloon against someones head, then try to pick up pieces of paper with the static, and then seeing if it would stick to someones jacket. Our observations was that the balloon picked up the paper but would not stick to a jacket. My hypothesis for this is that the static energy created by rubbing the balloon against the hair could not stay attached to something else when it already picked up the pieces of paper.
The second activity we did was to get two pieces of tape about ten inches long and stick it on the table. Then quickly pull them both off and see what they did. We found that the two pieces of tape moved away from each other. My hypothesis for this station is that the electromagnetic force which is that like atoms repel. I believe that it is electromagnetic force because the pieces of tape repelled away from the other piece of tape.
The third activity we did was to cut two pieces of tape about ten inches each. Then stick one piece of tape to the table and put the other piece of tape on the other piece of tape. Next quickly pull the two pieces off. We found that the two pieces of tape attracted to each other. I believe that the tape was attracted to each other because some of the electrons went to the other piece so there was a positive and negative, which caused it to come together.
Questions:
Why does the balloon not stick to the jacket? It has other times before for me...