Way back in 1836, Samuel F. B. Morse, along with Joseph Henry and Alfred Vail, invented an electrical telegraph system. Before telephones were invented, it could send messages over long distances by using pulses of electricity to signal a machine to make marks on a moving paper tape.

A code was necessary to help translate the marks on the paper tape into readable text messages. Morse developed the first version of this code.

His version included only numbers. Vail soon expanded it to include letters and a few special characters, such as punctuation marks.

The code — known as Morse code — assigned each number, letter or special character a unique sequence of short and long signals called “dots” and “dashes.”

In Morse code transmission, the short dot signal is the basic time measurement. A long dash signal is equal to three dots. Each dot or dash is followed by a short silence that’s equal to a dot.

If you wonder how they decided which combination of signals was assigned to each letter, they studied how often each letter in the English language was used.

The most used letters were given the shorter sequences of dots and dashes. For example, the most commonly used letter in the English language — E — is represented by a single dot.

The original telegraph machines made a clicking noise as they marked the moving paper tape. The paper tape eventually became unnecessary.

Telegraph operators soon learned that they could translate the clicks directly into dots and dashes. Later, operators were trained in Morse code by studying it as a language that was heard rather than read from a page.

Although Morse originally referred to code signals as dots and dashes, operators began to vocalize dots as “dits” and dashes as “dahs” to mimic the sound of Morse code receivers.

Today, it’s possible to transmit messages in Morse code in any way that dots and dashes can be communicated. This includes sounds and lights, as well as printed dots and dashes.

Morse code was critical for communication during World War II. It was also used as an international standard for communication at sea until 1999, when it was replaced by the Global Maritime Distress Safety System. The new system takes advantage of advances in technology, such as satellite communication.

Today, Morse code remains popular with amateur radio operators around the world. It is also commonly used for emergency signals. It can be sent in a variety of ways with improvised devices that can be switched easily on and off, such as flashlights.

The international Morse code distress signal ( · · · — — — · · · ) was first used by the German government in 1905 and became the standard distress signal around the world just a few years later. The repeated pattern of three dots followed by three dashes was easy to remember and chosen for its simplicity.

In Morse code, three dots form the letter S and three dashes form the letter O, so SOS became a shorthand way to remember the sequence of the code. Later, SOS was associated with certain phrases, such as “save our ship” and “save our souls.”

These were just easy ways to remember SOS, though. The letters themselves have no such inherent meaning.


74 Join the Discussion

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    • What a GREAT question, Clayton! We know that Morse Code was a super important form of communication during World War ll. It was also used as an international standard for communication at sea until 1999, so that tells us it was used during the Cold War, too! Thanks so much for commenting today! :-)

    • What a sweet thing to say, Liam! We love ALL of our Wonder Friends…thanks for being such an AWESOME one! :-)

  1. I never really thought about WHEN morse code was invented before… thanks for posting such a complete yet easy to read history! My hubby loves being a HAM and I’m trying to learn more about it so I can keep up with him :)

    • Thanks for posting this GREAT comment, Elizabeth! We’re glad you learned something new from this Wonder! :-)

    • Hi, Logan! We think it’s really cool that you sent us a message in Morse Code! We’re not sure of every word in your message, but we think we see the word, WONDERING. Are we right? :-)

  2. This website is really cool! My book had Morse code in it, so I was wondering about it. Thank you for posting about this topic!!! :)

    • We’re so glad you visited Wonderopolis today and learned some new things about Morse code, Haylie! Thank you for leaving us a comment! :-)

    • That sounds like a lot of FUN, Amoolya! Thanks so much for visiting Wonderopolis today and for leaving us this GREAT comment! :-)

  3. and what made u get so excited on morse code? i’m not saying that’s bad… i’m just… wondering… hee hee

    • Lylla- we got the first part of your WONDERful message that says “U Are” but we could not decipher the last part. Thanks so much for taking the time to treat us to a secret message :)

  4. i know this seems a little off topic but… does anyone like to draw? i LOVE it!!! it allows me to express myself for who i am without any criticism! i wish i could show u all because yr all wonderful people!!

  5. when is it and where i need all the details!!! i just recently joined a couple days ago so i dont know! lol

  6. i know this next question is really weird… but r u a person or computer… i warned u it was weird!!! i’m the type of person who asks weird questions!! lol

  7. and two more things 1st for the question how many flowers can a bee pollinate idk but heres a hint… a bee needs to visit over 2 million flowers to make 1 average size jar of honey and 2nd for the camp thing do i check this page or the home page?

    • Those are two GREAT questions (like we said- we love your sense of WONDER) :) That is one BUSY bee! For Camp, check out wonderopolis.org’s home page Monday mornings :)

  8. hey… well i just wanted to say my name isnt really lylla its morgan but a lot of my friends call me that… i dont really know why… anyway the only reason i did that is because i dont really trust new people… at first! but im really warmingup to u guys! i like to think of u guys as friends now! plz dont be offended that i lied about my name!

  9. and r u a boy or a girl? when i want to get to know someone i ask LOTS of questions!… some r even weird like the computer one! lol

    • We are a group of WONDERers :) It is great that you ask a lot of questions :) That helps keep us all WONDERing!

  10. yay! and do u like music! my fave band is Nightcore! they sound dark but their music is really good! my fave song is… well the name is strange but i like it the song is Angel with a shotgun… i told u it was strange but give it a try and tell me what u think of the song!!!

  11. Have you ever heard of Hatsune Miku? She’s my idol!! Well if you havent she’s a “vocaloid” a virtual voice–she’s known world wide!!! Everyone loves her!! She’s 16 but here’s the weird thing… she not real! She’s a hologram but she looks real and her voice is completley computer generated!! And so are her movements! She’s not even that tall, she’s only 5’2″.

    • Hey there, Nicole! Check out our Wonder for more information about who uses Morse code and why it was invented! :)

  12. Thank you for this wonder of the day . . . it fit in beautifully with our inventions unit! However, it was difficult decoding your message due to the fact that some of the dashes came out as single dashes. For example, instead of two small dashes it was a medium dash and instead of three small dashes it was a long dash. At least, that’s how it looked on my computer. Not to worry . . . I did figure it out!!

    • Hi Mrs. Lumpkin! Thanks for WONDERing with us! Morse code is definitely hard to decipher and takes some getting used to! Keep WONDERing with us! :)

    • Welcome, cookie! We are glad you loved this WONDER. We love seeing your enthusiasm about WONDERing!!!! Unfortunately, we did need to remove a few of your !, so that your comment would fit into the appropriate space (our comment section treats exclamation points differently than regular letters, and sends them flying off the right side of the page!). We hope you understand. We REALLY appreciate all the WONDERful comments you share with us when you visit! :-)

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Have you ever wondered…

  • Why was Morse code invented?
  • Who invented Morse code?
  • What does SOS mean?

Wonder Gallery

Try It Out

Ready to decipher some dits and dahs? We’ve used Morse code to encode a special message for all our Wonder Friends. Here it is:

.– …. .- – / .- .-. . / -.– — ..- / .– — -. -.. . .-. .. -. –. / .- -… — ..- -?

Print out a Morse code key and use it to decipher our special message. Note: The / is used to separate the words of the message.

When you’re finished, create your own special message and use your key to encode it using Morse code. Give your message and the key to someone else and challenge him or her to decode it!

If you enjoy communicating with your friends and family using Morse code, try this online Morse Code Translator to encode and decode even longer messages.

If you want, you can even email a secret message to Wonderopolis HQ using Morse code!


Still Wondering

Visit National History Explorer’s Morse Telegraph Register entry to learn how this machine used Morse Code to communicate messages.


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