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Electricity is a type of activity arising from the existence of charge. The basic unit of charge is that on the proton or electron. The protons charge is called positive while the electron’s is negative.
A particle of matter usually has a charge. The charge is positive or negative. Two particles with the same charges, both positive or both negative, repel or drive away each other, while two particles with unlike charges are attracted.
The negatively charged electrons in an atom are kept near the nucleus because of their attraction for the positively charged protons in the nucleus.
Materials differ in their ability to allow electricity to flow through them.
- Conductors allow electricity to flow through them easily. Copper wire is a good example and makes up our housing and appliance wiring.
- Insulators are materials that don’t allow electricity to pass through them easily. Materials such as rubber are good insulators and are used around appliance and house wires to keep the electricity from creating a short circuit.
- Semiconductors: conduct electricity under some conditions.
Electrostatics is the study of charges, or charged objects that do not involve moving charges or current. When positive or negative charge builds up on objects, static electricity occurs. The charge can be built up by rubbing certain objects together. The friction between the objects causes electrons to be transferred from one object to the another. The object that has lost the electrons has a positive charge and the objects act that has gained them has an equal negative charge. An electrically neutral object can be charged by bringing it in contact with a charged object: if the charged object is positive, the neutral object gains a positive charge when some of its electrons are attracted onto the positive object; if the charged object is negative, the neutral object gains a negative charge when some electrons are attracted onto it from the negative object. This may happen to a person when rubbing one’s feet on a carpet and then touching an object and receiving an electrical shock.
Electrodynamics is the study of charges in motion. A flow of electric charge makes up an electric current.
There are several things needed to complete an electrical circuit. There must be an electromotive force from batteries or generators, conductors such as copper wire and an appliance such as a bulb to be lit. A device called a switch can be used to stop or open the circuit or close or create the circuit. When a circuit is not completed because the electricity is diverted to a path of least resistance it is a short circuit.
In a simple circuit there are two types of wiring. One is a parallel circuit. This is when all the batteries and appliances such as bulbs are wired with the positive terminals of the batteries wired together and the negative terminals of the wired together so there are parallel pathways for the electricity to travel. In a parallel circuit, if one appliance such as a bulb goes out, the rest of the circuit remains on. The force from the batteries does not increase, however, if more batteries are added.
In a series circuit, the positive terminal or end of a battery is wired to the negative terminal of the other battery and the positive end of one appliance to the negative or terminal of the other appliance such as a bulb. Thus if one bulb or appliance goes out, the whole flow of electricity is interrupted and the circuit goes out. However, if more batteries are added to the circuit, the bulb will get brighter as more force will go to that bulb.
There are several basic units or measure with electricity.
- Ampere: measures electrical current.
- Coulomb: measures amount of charge
- Volt: measures electromotive force.
- Ohm: measures resistance to the flow of electricity through an .