Discovery of Electricity

This will show you everything about the discovery of electricity.

Our understanding of electricity has developed

slowly. Through experiments and discoveries

people learnt new knowledge. This allowed them

to do further experiments and to learn and understand

even more. Our knowledge of electricity

comes from the contribution of many people,

most from before our time.

The Italian Luigi Galvani was a professor of

anatomy. He studied the structure of animals. In

1791, he reported that the leg of a freshly killed

frog would twitch when touched with two different

metals at the same time. He wrongly thought

that this was ‘animal electricity’.

In 1800, Alessandro Volta explained that a

chemical reaction occurs between two different

metals in contact with a moist material. This

chemical reaction causes an electric current. An

electric current also caused the frog’s muscle to

twitch. The Italian scientist Volta had made the

first electrochemical cell. A group of electrochemical

cells is called a battery. Two different

metals in a solution, which is used to supply an

electric current, is called a galvanic cell (or electrochemical

cell). These are also called voltaic cells.

Many people experimented with galvanic cells,

batteries and electric circuits. In 1827 the German

physicist George Ohm described a mathematical

equation to link together the main electrical quantities.

This is now called Ohm’s Law, and is used in

designing all electrical devices from toasters to

computers.

In 1820 the Danish physicist Hans Oersted had

observed that a compass needle moved away from

north when an electric current flowed past it. He

was the first person to show a link between electricity

and magnetism. In the 1820s André

Ampère showed the mathematical connection

between electricity and magnetism. The ideas of

Ohm and Ampère are used to make

electromagnets, electric bells, speakers and remote

switches.

In 1831 two scientists, Michael Faraday in

England and Joseph Henry in USA, discovered

how to make electricity from magnetism. This idea

is now used in generators and dynamos, and the

principle is reversed to make electric motors. It is

also the basis of audio and video tapes, computer

discs and swipe cards. A combination of the ideas

of Ohm and Faraday are used in transformers.

Michael Faraday went on to discover

electrolysis. This is using electrical energy to cause

a chemical change. Electrolysis is now used to

obtain many substances and to electroplate

metals.

In 1864 the Scottish physicist James Clerk

Maxwell combined all the known ideas about

electricity and magnetism into mathematical

equations. He predicted the existence ofelectromagnetic waves, which include radio

waves, X-rays, and microwaves. These waves

were produced in 1887 by the German physicist

Heinrich Hertz. In 1895 the Italian inventor

Guglielmo Marconi used Hertz’s discovery to

broadcast the first radio message. These discoveries

are the basis of radio and television broadcasts,

satellite links and mobile phones.

Inventors were busy finding new applications

of electricity. The Scotsman Alexander Bell

invented the telephone in 1876. The American

inventor Thomas Edison invented the record

player in 1877. In 1879 he made the first cheap

and reliable electric light bulbs.

It was not until 1891 that the nature of electricity

became apparent. The Irish physicist

Johnstone Stoney explained that electricity was

the movement of tiny charged particles from

atoms. He named these particles electrons. In

1897 J.J. Thomson proved that electrons existed

in the atoms of all substances.

In the 1890s, teams of scientists made vacuum

tubes. These tubes contained wires that could

amplify, combine or separate electric currents.

Vacuum tubes needed a high temperature and

high voltage to work properly. They were bulky

and expensive. They were used to make the first

television sets and radio receivers, and some

electronic devices such as radar.

Transistors were invented in 1947 by a team of

American physicists. Transistors do the same job

as vacuum tubes, but they are smaller, more

durable and use much less energy. Millions of

interconnected transistors can now fit onto an

integrated circuit (IC or ‘chip’). They are the main

reason that electronic equipment is becoming

smaller, lighter and more powerful.

There is still much more to be invented and

discovered. Better solar cells are needed to obtain

the energy from sunlight. Electric cars are not yet

practical because there are no batteries that can

store enough electrical energy. Super conductors

will revolutionise the electrical and electronic

devices of the future.

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3 Responses to “Discovery of Electricity”
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  3. Mark Valente Says...

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