Key point
- Electricity is a basic part of nature.
Electricity is a secondary energy source.
Electricity itself is neither renewable or non-renewable.
Applying a force can make them move from one atom to another. These moving electrons are electricity.
A battery produces electricity using two different metals in a chemical solution.
The end that frees more electrons develops a positive charge and the other end develops a negative charge.
A chemical reaction between the metals and the chemicals frees more electrons in one metal than in the other.
circuit, measured in Coulombs/second which is named Amperes.
The standard abbreviations for the units are 1 A = 1C/s
Voltage is electric potential energy per unit charge, measured in joules per coulomb ( = volts).
It is often referred to as "electric potential", which then must be distinguished from electric potential energy by noting that the "potential" is a "per-unit-charge" quantity.
The difference in voltage measured when moving from point A to point B is equal to the work which would have to be done, per unit charge, against the electric field to move the charge from A to B.
We use a lot of energy - in our homes, in businesses, in industry, and for traveling between all these different places.
What is electricity?
Electricity is a basic part of nature and it is one of our most widely used forms of energy. And it flow of electrical power or charge.
How is electricity being produced?
Electricity is a secondary energy source which means that we get it from the conversion of other sources of energy, like coal, natural gas, oil, nuclear power and other natural sources ,which are called primary sources.The energy sources we use to make electricity can be renewable or non-renewable, but electricity itself is neither renewable or non-renewable. Despite its great importance in our daily lives, most of us rarely stop to think what life would be like without electricity. Yet like air and water, we tend to take electricity for granted. Everyday, we use electricity to do many jobs for us -- from lighting and heating/cooling our homes, to powering our televisions and computers. Electricity is a controllable and convenient form of energy used in the applications of heat, light and power.
In order to understand how electricity charge moves from one atom to another, we need to know something about atoms. Everything in the universe is made of atoms—every star, every tree, every animal. The human body is made of atoms. Air and water are, too. Atoms are the building blocks of the universe. Atoms are so small that millions of them would fit on the head of a pin.
Atoms are made of even smaller particles. The center of an atom is called the nucleus. It is made of particles called protons and neutrons. The protons and neutrons are very small, but electrons are much, much smaller. Electrons spin around the nucleus in shells a great distance from the nucleus. If the nucleus were the size of a tennis ball, the atom would be the size of the Empire State Building. Atoms are mostly empty space.
If you could see an atom, it would look a little like a tiny center of balls surrounded by giant invisible bubbles (or shells). The electrons would be on the surface of the bubbles, constantly spinning and moving to stay as far away from each other as possible. Electrons are held in their shells by an electrical force.
The protons and electrons of an atom are attracted to each other. They both carry an electrical charge. An electrical charge is a force within the particle. Protons have a positive charge (+) and electrons have a negative charge (-). The positive charge of the protons is equal to the negative charge of the electrons. Opposite charges attract each other. When an atom is in balance, it has an equal number of protons and electrons. The neutrons carry no charge and their number can vary.
The number of protons in an atom determines the kind of atom, or element, it is. An element is a substance in which all of the atoms are identical . Every atom of hydrogen, for example, has one proton and one electron, with no neutrons. Every atom of carbon has six protons, six electrons, and six neutrons. The number of protons determines which element it is.
Electrons usually remain a constant distance from the nucleus in precise shells. The shell closest to the nucleus can hold two electrons. The next shell can hold up to eight. The outer shells cans hold even more. Some atoms with many protons can have as many as seven shells with electrons in them.
The electrons in the shells closest to the nucleus have a strong force of attraction to the protons. Sometimes, the electrons in the outermost shells do not. These electrons can be pushed out of their orbits. Applying a force can make them move from one atom to another. These moving electrons are electricity.
BATTERIES PRODUCE ELECTRICITY
A battery produces electricity using two different metals in a chemical solution. A chemical reaction between the metals and the chemicals frees more electrons in one metal than in the other. One end of the battery is attached to one of the metals; the other end is attached to the other metal. The end that frees more electrons develops a positive charge and the other end develops a negative charge. If a wire is attached from one end of the battery to the other, electrons flow through the wire to balance the electrical charge. A load is a device that does work or performs a job. If a load such as a lightbulb is placed along the wire, the electricity can do work as it flows through the wire. In the picture above, electrons flow from the negative end of the battery through the wire to the lightbulb.
The electricity flows through the wire in the lightbulb and back to the battery.
What is Electric Current?
Electric current is the rate of charge flow past a given point in an electric circuit, measured in Coulombs/second which is named Amperes. In most DC electric circuits, it can be assumed that the resistance to current flow is a constant so that the current in the circuit is related to voltage and resistance by Ohm's law. The standard abbreviations for the units are 1 A = 1C/s
.
What is Voltage ？
Voltage is electric potential energy per unit charge, measured in joules per coulomb ( = volts). It is often referred to as "electric potential", which then must be distinguished from electric potential energy by noting that the "potential" is a "per-unit-charge" quantity. Like mechanical potential energy, the zero of potentil can be chosen at any point, so the difference in voltage is the quantity which is physically meaningful. The difference in voltage measured when moving from point A to point B is equal to the work which would have to be done, per unit charge, against the electric field to move the charge from A to B.
Used to calculate current in Ohm's law
Used to express conservation of energy around a circuit in the voltage law
Used to calculate the potential from a distribution of charges
Is generated by moving a wire in a magnetic field
Uses of electricity?
Take a look at all the things we depend on each day that need electricity:
In the kitchen:
Refrigerators
Dishwashers
Stoves
In the family room:
Lamps
Computers
Air conditioning
In the basement or utility room:
Washer and dryer
Furnace
Water heater
Outdoors:
Outdoor lighting
Electric lawn mower
Pool heater
Example:
The United States is a highly developed and industrialized society. We use a lot of energy - in our homes, in businesses, in industry, and for traveling between all these different places.
The industrial sector uses about one-third of the total energy. The residential and commercial sectors combined use even more than this - 40 percent of all energy. These two sectors include all types of buildings, such as houses, offices, stores, restaurants, and places of worship. Energy used for transportation accounts for more than a quarter of all energy.
From this topic,I know Electricity is a form of energy produced by the movement of electrons. Electricity is electrical power or an electric current. This form of energy can be sent through wires in a flow of tiny particles. It is used to produce light and heat and to run motors. Electricity is a basic feature of all matter, of everything in the universe.
Websites
http://www.eia.doe.gov/kids/energyfacts/sources/electricity.html
http://images.google.cn/images?complete=1&hl=zh-CN&rlz=1T4SKPB_zh-CNSG272SG272&q=electricity%20&um=1&ie=UTF-8&sa=N&tab=wi
http://42explore.com/electric.htm
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