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
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
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
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.