Electricity and the Atom
Everything, from wood to metal to gas to human beings is made of atoms. Within an atom are three basic components: the neutron, the proton, and the electron. The smallest of these components is the electron, which carries a negative electrical charge. The electron's electrical charge is the smallest quantity of electricity that exists. There are 115 different types of atoms, one for each know element. The Hydrogen atom has one electron. The ununoctium atom has 118 electrons. The electrons orbit around the nucleus of the atom in layers called energy levels.

The nucleus, or core of the is called the nucleus. The nucleus has two main components, neutrons and protons. The protons have a positive electric charge.. In a stable atom, the positive charge of the nucleus is always equal to the sum of its negatively charged electrons. Unstable atoms have either more protons or more electrons. They are unstable because the atom has either a negative or positive charge. Neutrons have no electrical charge. They are electrically neutral.

In the atom, the "opposite," positive and negative, electrical charges are strongly attracted to each other. There is also a strong opposing force between two charges of the same kind. The positive protons in the nucleus and the negative electrons are attracted to each other. This attraction is similar to the attraction between the opposite poles in two different magnets. Two negatively charged electrons will repel each other and so will two positively charged protons. This repulsion is similar to the repulsion of the similar poles of two different magnets.

In a normal atom the positive charge on the nucleus is exactly balanced by the negative charges on the electrons. It is possible, under certain circumstances, for an atom to lose one of its electrons. When this happens, the atom has a positive charge because it has an "extra" proton. The result is called an "ionized" atom and, in this case, it is a positive ion. It is also possible for an atom to pick up an extra electron. This atom would then also be called an "ionized" atom. It would be a negative ion.

A positive ion will attract any stray electron that is nearby. One way it can do this is to attract a single electron or the extra electron from any negative ion in the vicinity.

Some atoms, especially copper, silver, and gold atoms, among others, give up their electrons more easily than others. When we apply a positive electrical charge to one end of a cluster of these atoms, by attaching a battery or plugging in a plug, and a negative electrical charge to the other end of this cluster of atoms, we initiate a flow of electrons through this cluster. The electron from one atom will be attracted to the next atom in the direction of the positive charge. The atom will jump out of its orbit in its atom into the orbit of the next atom. This movement of electrons from atom to atom is what we call an electric current. The quantity of electrons that make up the current can be measured. The unit of measurement is called an Ampere or Amp.. This is very similar to flowing water. The water molecules represent electrons, and the movement of water in a stream represents current flow.

The amount of electric current is measured by determining the total amount of electrons flowing past any point in the circuit. If we use the water flow as an example, it would be how much water travels past a single point on the shore of a stream.

Conductors and Insulators
As we have seen, some atoms give up their electrons very easily. Other atoms do not give up their electrons at all, even when the outside electric force is very strong. Materials that give up their electrons easily are called "conductors." The following list of materials have atomic structures that make them good conductors.

• Metals: gold, silver, copper, zinc, steel, etc.
• Carbons
• Acids
• Water

Wireis made from metal that has high conductive properties. Gold is one of the best conductors in the metal family. Gold is also very expensive.; That is why wires are commonly made of copper. It is far less expensive than gold, and it has very excellent conductive properties.

Materials that do not permit their electrons to move from atom to atom are called insulators. This list gives some examples of common materials that are insulators.

• Dry Air
• Wood
• Porcelain
• Glass
• Rubber

As an electron jumps from its orbit into another atom's orbit, heat is produced. The more s electrons flowing in a conductive material, the greater the heat. The human body is composed of materials that can conduct electrons. .It is very possible that, if we come in contact with a high voltage source, our body could be severely burnt. That is why electricians wear rubber gloves when they work with electricity. A thin strip of tungsten on the other hand will conduct electrons as well. The more electrons flowing the greater the heat. As the heat increases it reaches a point where the energy from the jumping electrons product so much heat that they produce light.

Resistance
Some metal atoms require more stimulation to pass on their atoms. The atoms of two different metal wires of the same size and shape will not behave in the same way. The amount of electron flow, or current that flows between atoms and through the cluster of atoms shaped like a wire can also be measured. This resistance to give up atoms of one given metal is called its "resistance." A metal with a low resistance value allows a higher current flow. The metal with a high resistance value allows a lower current flow Resistance is measured in a unit of measurement called an "Ohm." The greater the resistance that a metal has, the greater the heat that it will produced as the electrons move from one atom to the next. Light bulb use tungsten or gas to conduct electricity. The higher resistance of these materials produces higher heat and light. A toaster is another excellent example of using the wires electrical resistance to produce heat to toast toast.

The resistance of a cluster of atoms in the shape of a wire can be doubled if you double the length of the cluster, or wire. A copper wire ten feet long will have twice the resistance as a five-foot piece of the same wire. The longer the path that a current must flow in a conductor, the higher the resistance will be.

Sidebar: Using their knowledge of resistance and conductance, scientists created "packages" to control resistance in very small circuits. These packages of bundled forms of carbon were made up into a single short package with a wire on each end and called a resistor. Carbon is a conductor with very unique and predictable properties of conductance.

A wire with a positive charge attached to one end and a negative charge attached to the other is called a circuit. The amount of charge that is applied to the negative end of the wire is measured using a unit called a Volt. A volt is an example of what is called an electromotive force, or emf.

Scientists have discovered a relationship between these different units of measure. The relationship can be expressed like this: a cluster of atoms in the form of a wire has a resistance of one ohm, when an emf of one volt attached to it causes enough electrons to "jump their orbits" and create one amp of current flow.

An Electric Circuit
An electric circuit has to have three different things if it wants to be called an electric circuit. It needs a source of voltage or electromotive force. This source could be an outlet in your wall or a battery or a solar cell. It needs a path of atoms, like the wires in your home or in Space Station Alpha, and it needs something that offers resistance greater than the wires, like a light bulb or a radio transmitter or an electric fan, etc.

A complete circuit must have an unbroken path so current can flow from the source of the electromotive force, through the "current path," through the resistance, and back into the electromotive force. If the circuit becomes broken, or open, like when somebody "turns off" a switch the current cannot flow.