Electricity Homework

1. Something becomes charged when rubbed against another object. An object becomes charged because electrons are rubbed off from one object to another. An ion is an atom that has had an electron removed.

2. A atom is composed of negatively charged electrons circling a nucleus of positively charged protons and neutrons with no charge.

3. An neutral item becomes polarized when it is put by a charged object. It becomes polarized because the charged object (depending on whether it is positive or negative) either attracts or repels the nuclei in the atoms of the neutral item and attracts or repels the electrons in object. This creates a charge shift in the neutral object and attracts or repels the charged object more strongly than the other, this makes the object polarized.

4. An insulator is a material that is hard to transfer charge from. A conductor is a material where electrons are easily moved off and on to.

5. When two items are electrically attracted it means that the object have opposite charges so they attract or that one is charged negative and the other is neutral so the items attract.

6. A negatively charged balloon picks up neutral pieces of paper because the paper becomes polarized and the positive charges of the paper are closer to the balloon therefore stronger than the negative charges in the paper so the balloon and paper attract because they have opposite charges.

7. An electric field is something a charge has to fill up space. If another charge gets into the electric field, the electric forces act upon it. A test charge shows how strong the electric field is depending on where you stand with it. The closer to the charge, the stronger the force of the electric field. The charge will repel or attract a charge from any direction.

8. Electric potential is measured in joules per coulomb, known as a volt. This measures energy per charge. Electric potential is the potential energy in an electric field of a charge.

Van De Graff Observations

In class we conducted many experiments using a Van De Graff. A Van De Graff takes electrons from a brush on the bottom of it and moves them up to the other brush and then expels them into the metal dome.
When balloons were blown toward the Van De Graff they were initially attracted. Then at some point when the bubbles got near the Van De Graff they started to repel. At one point a human chain was formed with the last and first person touching the Van De Graff. When a person not in the chain touched a person in the chain they were shocked. I think this was because the energy from the Van De Graff was transferred to the people in the chain and when an outsider touched one of them the shock was a transfer of energy. In one test napkins were placed on the Van De Graff. When the machine was turned on the napkins all flew off except for one. The one that stayed on the machine was attracted to it. I think this is because the napkins had the same electric charge so they repelled each other but when there was just one then there wasn't other napkins to repel from so it was attracted to the strong pull of the Van De Graff. In another experiment paper strips were taped to the sides of the Van De Graff. When the machine was turned on, the paper strips flew up. I think this is because the machine and strips had the same electrical charge because the energy came from the Van De Graff. The strips flew up because they were trying to repel the other strips and the machine. When the wand was put near the Van De Graff the strips were attracted to the machine. In one experiment cheerios were place on top of the dome. When the Van De Graff was turned on the cheerios flew off the dome. I think this is because some of the energy from the dome was transferred to the cheerios which gave them the same electrical charge. Since they had the same electrical charge they repelled each other.

Questions
How does the wand affect the electrical charge of other objects?

Electricity Stations Reflection

In the first station we had to rub a balloon against someone's clothes or hair. Then we put the balloon over paper and foil. The foil and paper stuck to the balloon. I think this is because the static electricity charged the balloon positively or negatively and the paper and foil had the opposite charge which made them attract.
In the second station we stuck two pieces of tape on the table and then ripped them off. When they were put near each other they repelled. This meant the had the same electric charge. I think this is because the same material had the same things done to them so they were bound to have the same electrical charge.
In the third station we had to fold a little of an end of two strips of tape and stick them on top of each other. Then we ripped them apart. When they were put near each other they attracted which means they had opposite electrical charges. I think this is because the friction from the rip caused one strip to get more neutrons and the other to get more electrons.
In the fourth station we had to wet a balloon and then dry it off. After that we had to rub it against a piece of clothing and see what would happen if we put it near running water from a sink. When this was done, the water and the balloon attracted each other so the water looked like it was bending. This means that the balloon and water had opposite charges (one negative and positive). I think this means that the balloon started neutral and then it lost or gained neutrons or protons which made it negatively or positively charged.

Questions
What exactly is an atom?
What is the difference between a cell and an atom?