Carry out some time trials and gather some data to help you decide
on the best training regime for your rowing crew.
Imagine picking up a bow and some arrows and attempting to hit the
target a few times. Can you work out the settings for the sight
that give you the best chance of gaining a high score?
Can you decide whether these short statistical statements are always, sometimes or never true?
Morse code was invented
by an American called Samuel Finley Breese Morse, (1791-1872). He
was not only an inventor but also a famous painter.
Before the invention of the telegraph, most messages that had to be
sent over long distances were carried by messengers who memorized
them or carried them in writing. These messages could be delivered
no faster than the fastest horse.
In 1830, Joseph Henry (1797-1878) made the first long-distance
telegraphic device. After becoming interested in electricity in
1827, Samuel invented a telegraph system which was the first device
for sending messages using electricity. Telegraph messages were
sent by tapping out a special code for each letter in the form of
long and short signals. Short signals are referred to as dits
(represented as dots). Long signals are referred to as dahs
(represented as dashes). The code was converted into electrical
impulses and sent over telegraph wires. A telegraph receiver on the
other end of the wire converted the impulses back into to dots and
dashes, and decoded the message.
In 1844, Morse demonstrated the telegraph to the United States
Congress using a now famous message "What hath God wrought"..
Samuel Morse Telegraph Receiver
Smithsonian National Museum of American History
Morse's original code was not quite the same as the
one in use today as it included pauses as well as dahs and dits.
However, a conference in Berlin in 1851 established an
international version, which is shown below:
The most well-known signal sent using Morse Code is:
. . . - - - . . .
and is the distress signal SOS.
Morse code requires the time between dits and dahs, between
letters, and between words to be as accurate as possible.
A Dit takes - 1 unit of time
A Dah takes - 3 units of time
The pause between letters - 3 units of time
The pause between words - 7 units of time
The speed at which a message is sent in Morse code is normally
given in words per minute (WPM). The word "Paris" is used as the
length of a standard word. How long does this take? (Answer is
given at the end of the article). An experienced Morse code
operator can send and receive messages at a rate of 20-30 WPM.
One of Morse's aims was to keep the code as short as possible,
which meant the commonest letters should have the shortest codes.
Morse came up with a marvellous idea. He went to his local
newspaper. In those days printers made their papers by putting
together individual letters (type) into a block, then covering the
block with ink and pressing paper on the top. The printers kept the
letters (type) in cases with each letter kept in a separate
compartment. Of course, they had many more of some letters than
others because they knew they needed more when they created a page
of print. Morse simply counted the number of pieces of type for
each letter. He found that there were more e's than any other
letter and so he gave 'e' the shortest code, 'dit'. This explains
why there appears to be no obvious relationship between
alphabetical order and the symbols used.
Paris = 34 time units.
You can download a
morse code font for windows here.