ELECTRICITY
Electricity has invaded our lives and has become vital in almost all aspects of society today. The list of uses will fill a book but here are a few headings: Transport Trains, buses, trams and cars all use electricity. Many use it as the motive power, meaning that electricity drives the wheels to make the vehicle move. Even gas and diesel powered vehicles use electricity to start the engines, control the engine and power the ancillary devices.
Home Heating, lighting, television, radio, computer, telephones all rely on electricity. Even wireless lights such as solar powered lamps will convert sight to electricity.
Communication As well as providing power for computers, cell phones, fixed phones, electricity is used as the medium for the transmission of signals. Even high speed optical fibers rely on an electrical signal at each end of the line. Without electricity, communication would be reduced to letters, flag waving and lighting fires and shouting at each other. None of the electricity free methods are as flexible as any that we are used to using today
Industry Manufacturing relies on electricity to drive virtually every moving part in a factory. Saws, cutters, conveyor belts, furnaces, chillers - whatever the process, electricity is involved somewhere.
Entertainment The MP3 player, the portable battery powered radio, memory stick are all accepted as part of our everyday lives. All rely on electricity to operate. Whether connected to a mains supply or battery, they all use electricity.
The list is by no means complete. Take a look around you: if it moves, lights up or makes a noise, it probably uses electricity. (pet dogs and cats excluded of course).
Come to think of it, even animals and people use electricity for senses and muscle control, so perhaps the pet dog or cat should be included after all!
WHAT IS ELECTRICITY?
It is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire. In addition, electricity encompasses less familiar concepts such as the electromagnetic field and electromagnetic induction.
The word is from the New Latin ēlectricus, "amber-like", coined in the year 1600 from the Greek ήλεκτρον (electron) meaning amber, because electrical effects were produced classically by rubbing amber.
Benjamin Franklin was a famous American. He lived in the 1700s. People did not know much about electricity then. Benjamin Franklin watched lightning in the sky. He thought that it looked like a giant spark. He wondered if lightning is electricity.
One day he tried to find out by flying a kite in a storm. He put a wire on a kite string. Lightning hit the wire on the kite. An electric charge went down the west string. The charge went down the wet string. The charge hit the key and made a spark. This told Benjamin Franklin that lightning was indeed electricity.
Do not try this experiment yourself. Lightning is very dangerous. Benjamin Franklin was lucky he was not killed.
In general usage, the word "electricity" adequately refers to a number of physical effects. In a scientific context, however, the term is vague, and these related, but distinct, concepts are better identified by more precise terms:
Electric charge: a property of some subatomic particles, which determines their electromagnetic interactions. Electrically charged matter is influenced by, and produces, electromagnetic fields.
Electric current: a movement or flow of electrically charged particles, typically measured in amperes.
Electric field: an influence produced by an electric charge on other charges in its vicinity.
