Saturday, April 11, 2015

What is Electricity ?

We use electricity everyday. Without it we would not be able to watch t.v., listen to the radio, have hot water, use a microwave to heat our food and many of the other things we do every day.

But what is electricity ?

First you have to know what an atom is. An atom is the smallest part of something. It is microscopic and every thing is made up of atoms.

Atoms are made up of three parts. They are

Protons These parts of an atom have a positive charge. They are in the middle of the atom, called the nucleus and they do not move.

Neutrons These parts of an atom have no charge. They are neutral and part of the nucleus of an atom with the protons.

Electrons These parts of the atom are very small and weigh a lot less then the protons and neutrons. Electrons are not part of the nucleus of the atom, instead they move around in orbits outside the nucleus. Electrons are the only part of an atom that moves.

So what does this have to do with electricity ?

Electricity is the flow of moving electrons. When the electrons flow it is called an electrical current.

To understand why electrons flow you need to understand that atoms can lose electrons by rubbing against another material. Think about when you rub your head against a balloon. Believe it or not, your hair is actually getting some electrons from the balloon. Because your hair has more electrons then protons, we say it is negatively charged.
But what about the balloon? Well the balloon has more protons than electrons so it is positively charged.

Electricity is the flow of electrons through a conductor. Materials that conduct electricity easily have a weak hold on their outermost electrons, allowing them to move easily from one atom to another. When an electron moves to an adjacent atom, it displaces another electron, and this flow is electric current.

The flow of electrons is caused by the electrical charge of particles. Electrons have a negative charge, and protons have a positive charge. When an atom loses an electron, it becomes positively charged. When an atom gains an extra electron, it becomes negative. Since like charges repel, an electron moving from one atom to another displaces other electrons, pushing them further down the line.

Since electric current is caused by the flow of electrons, in a metallic conductor, it is the flow of negative charges through the material. However, in other materials, such as semiconductors, the charge carried can be positive or neutral. Benjamin Franklin, in his studies of electricity, theorized the possibility of positive charge carriers and created a standard that electrical engineers use to this day. To simplify electrical diagrams, the current is shown to flow from the positive to the negative pole, even though in many cases the negative pole is the originator of the current.

Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field. There are two types of electric charges: positive and negative. Positively charged substances are repelled from other positively charged substances, but attracted to negatively charged substances; negatively charged substances are repelled from negative and attracted to positive. An object is negatively charged if it has an excess of electrons, and is otherwise positively charged or uncharged.

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