Download Worksheet 1 - Connected Earth

Secondary
Project
11-14's
Worksheet 1
The first steps to a Connected Earth
Telecommunications is the science and technology of transmitting information electronically
over distance, using radio signals or electrical or optical lines. Telecommunications isn't a
modern idea. The word comes from the Greek word 'tele' meaning 'far away'.
You are going to explore the building blocks that led to mass telecommunications and
consider the impact of discoveries that have profoundly changed our world.
Bounce back in time
1. Use the timeline on this and the next page to trace the development of the first steps of
communications. Make notes as you read it on the developments you feel are most
significant in preparation for the questions in the following worksheets.
1729 Gray discovers conductivity. He shows that static charges of electricity could be
conducted by some materials but not others.
1750
1753 Morrison suggests using 26 wires (one for each letter of the alphabet) to send
messages over long distances.
1774 Lesage sets up a simple telegraph between two rooms using 24 wires.
1793 Chappe brothers develop the 'tachygraph' - a system of 'mechanical semaphore
arms' that can form different shapes to send messages.
1800
1798 Salva proposes long distance electric telegraph lines, overhead, overground and
running under the sea.
1809 Sommering develops telegraph of 35 wires (one for each number and letter).
1820 Oersted places compass next to electrical wire - the compass needle moves at right
angles to wire when electric current on - links electricity and magnetism.
1820 Ampere discovers how electric currents behave and how to measure them.
1832 Schilling coils electrical wire around magnetised needle - it swings one way or
another, depending on direction of current.
1833 Gauss and Weber send signals over 2 km - moving needles point to letters
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Secondary
Project
11-14's
Worksheet 1
1835 Morse builds electromagnetic pendulum carrying a pencil in contact with a moving
strip of paper.
1837 Cooke and Wheatstone develop needle-telegraph system - needles point to letters to
spell out words and successfully sends message over several miles.
1842 First commercial telegraph service from London
Paddington to Slough.
1847 An inelastic latex substance called Gutta Percha
(an ideal electric wire insulator) makes undersea cable
laying a possibility.
1850
Mid-1850s Morse develops system to hear telegraph
signal and code to carry information - trained operators
can translate incoming messages quickly.
The laying of the first translantic cable
1858 Successful but short-lived telegraph cable laid across the Atlantic.
1861 Reis creates a transmitter diaphragm to send music electrically for the first time.
1866 Cable across the Atlantic completed after several failed attempts.
1870 UK telegraphs taken over by the Government / Post Office. Lines start to reach many
more towns and many villages.
1872 Telegraph starts to be used in businesses in offices, banks, gentlemen's clubs and
leading hotels.
1874 Baudot develops 'multiplex' telegraph system - four messages can be sent at the
same time.
1875 Bell develops a prototype telephone that sends and reproduces complex sound.
A year later he develops first telephone using speech.
1877 First telephones arrive in the UK.
1878 Investors obtain British rights to the invention, and begin to sell telephones for
private use.
1879 UK's first public telephone exchange - an exclusive club of eight subscribers.
1880 First telephone directory with 250 subscribers.
1884 Telephone line links London to Brighton.
1891 First submarine telephone cable between England and France. Strowger develops
automated switching machine for the telephone exchange - callers no longer need to be
connected manually.
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