Physics - Fizik

ELECTRICITY IS AN INVISIBLE form of energy. It is based on the tiny charged particles inside atoms. In an atom's nucleus, particles called protons have a positive charge. Whizzing around the atom's nucleus are electrons, which have a negative charge. Normally, the positive and negative charges balance. If they become unbalanced, an electrical force is produced. This may stay in one place, as static electricity, or move from place to
place, as a flowing current. Electricity is so useful to us because it can flow along wires to
wherever we need it, and be changed into other forms of energy such as light, heat and movement.


The electricity network

Power stations turn the energy of movement into electrical energy which is medium strength, or mid voltage. This is changed into more powerful, high-voltage electricity and sent along large cables or wires, high on pylons or buried underground. This network of cables and wires is called the electricity distribution grid. The electricity is changed back into lower-power forms, industrial and mains voltage, for use in factories, farms, offices and homes.


Electricity in atoms

Everything is made up of trillions of incredibly tiny particles, called atoms. An atom has a central nucleus containing protons, each with a positive charge, and neutrons, each with
no charge, or neutral. Going around the nucleus in empty space are much smaller particles, called electrons, each with a negative charge. When atoms or substances gain or lose electrons, they become electrically charged. Gaining electrons makes them negative. Losing electrons makes them positive.


Electricity at work

If there was a power cut in this city, people would have to manage without most of their lighting and heating, and the machines that make their lives so much easier. Daily routine would grind to a halt and the only sources of energy would be batteries, candles, wood, coal or gas. Yet people managed without electrical devices for thousands of years, and still do in many parts of the world. It is only in the last century or so that electricity has been put to work. One of its great advantages is that it is available at the flick of a switch.