The first Morse code message was sent in 1844. This is why Morse code sent over the telegraph is now known as the Victorian Internet, as it was the first system that allowed global communication.
Dots and dashes were transmitted over the electric cables using a ‘key’ device that allowed the operator to send messages typically at 35 words per minute. This has been tested against modern teenagers using text on their mobile phones and found to be faster!
| ·− | A | −··· | B | −·−· | C | −·· | D | · | E |
| ··−· | F | −−· | G | ···· | H | ·· | I | ·−−− | J |
| −·− | K | ·−·· | L | −− | M | −· | N | −−− | O |
| ·−−· | P | −−·− | Q | ·−· | R | ··· | S | − | T |
| ··− | U | ···− | V | ·−− | W | −··− | X | −·−− | Y |
| −−·· | Z |
The sequence of dots and dashes are sent with a short pause between each letter to allow a skilled listener to identify them individually using the above table. That short pause is essential, as without it the listener would not be able to tell which letter was being sent and the message would be ambiguous.
The sequence for CAT would be −·−· ·− −
If the spaces are taken out −·−··−− it becomes very difficult to reconstruct the original message as there are many possibilities that it could be, depending on where you put the spaces. This is a hard problem to solve, even using the raw processing power of a computer! Here are some possible alternatives.
| Chunk | −·−· | ·− | − | − | · | −··− | − | −·− | ·· | −− | ||
| Alphabet | C | A | T | T | E | X | T | K | I | M |
Challenge
Can you convert the following Morse codes with the spaces taken out into words that can make a phrase? (Clue: this is what you want your students to do).
−······−·−·−·····−·−·−··
ANSWER:
Think hard
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