There are three types of static charges: negative, positive and neutral.
Laws of electric charge
1. Like charges repel (eg. negative and negative)
2. Opposites attract (eg. negative and positive)
3. Uncharged objects are attracted to anything but themselves (eg. neutral and positive/negative)
-friction (rubbing)
-contact (touching)
-induction
Electrostatic Series: a chart that lists substances in order from the weakest hold of electrons to the strongest (on the bottom). The one that is higher than the other object that is being rubbed will be positively charged.
Charging by Friction
Initially, both neutral. The one that is lower on the electrostatic series takes the electrons from the one that is higher on the electrostatic series, and becomes charged. The protons from the one that is higher on the electrostatic series remain because protons can not be transferred (can not move).
Charging by Contact
With contact, electrons can tranfer from one substance to another.
Example: A neutral substance will take the electrons from the charged substance, but the charged substance will never become neutral, only losing some electrons because electrons are attracted to the protons in the neutral object.
Charging by Induction
Negatively charged object goes near a neutral and the positives in the neutral will attract the charged object. The electrons from the neutral object will move to the area where is it farthest from the charged object.
If you attach a wire to the neutral object, the negative electrons from the neutral object (after being touched with the charged object) will move out through the wire because they want to be as far away from the charged object as they can.
Induced Charge Seperation
Induced charge seperation is only when the protons and electrons seperate into different directions and aren't spread evenly throughout the substance.
For example, if you have a dust particle and a TV screen, the dust particle doesn't need to be touching the screen to cause the induced charge seperation. The TV starts to become charged because of the long use, so the dust particles get attracted to it (but don't touch). Then the electrons/protons change position in the dust particle and TV screen. The electrons move towards the surface of the TV screen and the closest part of the dust particle becomes positive.
But the TV remains negatively charged and the dust particle remains neutral; nothing is being changed except for the placing of the particles.
In winter, there is less moisture, therefore less water in the air, and is easier to get shocks because of the static everywhere.
Insultators: hold onto electrons.
Electrostatic Air Cleaners: Dust particles in the house, car, etc. are very dangerous and need to be removed. The electrostatic air cleaner can do the job. It sprays the air with positive ions to make the atmosphere non-pollutant and neutral.
Grounding: connecting a charged object to the ground. When lightning strikes, a lot of electrons appear and need to be directed to the ground, thus "grounding" with lightning rods.
Discharging at a point: a pointed, rounded object can discharge at the pointing point because the electrons try to leave the surface because the air is neutral, and continue to move down towards a specific point. When the electrons all reach the point, they will repel so strongly (because they're all electrons), they will move away from one another and immediately get neutralized.
This is also why airplanes' wings have a point; it would be dangerous to not have a rounded point at the fin.
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