As you’ve probably pieced together from our last posts, there are many ways to send secret messages. From invisible ink to Caesar ciphers, a lot of the time, a code is written out on a slip of paper for others to unscramble. But sometimes, secret messages don’t come in traditional forms.
Morse code was invented by Samuel F. B. Morse in the 1830s. It was originally created to work in conjunction with his other famous invention, the telegraph. The telegraph could send messages quickly using electrical signals that would travel over wire (see picture below).
The key is pressed down multiple times to create messages. By pressing down the key, the electrical circuit is closed, and either a dash or dot is sent via an electrical current to the recipient of the message. Messages are able to be recorded when received in part because of the electromagnet. The electromagnet is, in essence, a metal core wrapped in a coil. The electrical current travels through the coil and briefly magnetizes it. During this short time, an iron armature, with a pencil attached, is attracted to it for as long as it takes for the pencil to record a dot or dash on the paper.
The receiver would then translate these dots and dashes from Morse code to English. However, later, it was discovered that those operating the telegraph could understand the message just by hearing the machine, so the paper was replaced by machines that made louder beeping noises.
So what’s all this nonsense about dots and dashes? Well, Morse code is entirely made up of them! Look at the picture below:
Dashes and dots, or, if spoken aloud, dahs and dits, make up the letters and words in Morse code! In the right combination, they can form secret messages. The alphabet below tells you which combinations of dashes and dots form which letters:
Remembering the combinations of dashes and dots can be tricky. Luckily, there’s a tree diagram you can use to help (see below)!
To use the diagram, start at the place where I’ve written “START.” Whenever you take a left down the “branches” of the diagram, it means that you add a dash, and whenever you take a right, add a dot.
For example, if I wanted to send the letter N, to get there, I need to go left down the diagram. This means that the letter N in Morse code begins with a dash. However, by just going left once, I land on the letter T, which is not the letter N, so I know I have to keep going.
To get to the letter N, this time, I have to choose the right branch instead of the left. Since I have arrived at the letter N, I don’t need to add any more dots or dashes. Therefore, I know the letter N in Morse code is a dash and then a dot.