A Morse code lesson plan for the classroom
This Morse code lesson plan fills one period of 50 to 55 minutes: a five-minute history hook, timing taught as rhythm, pairs sending and receiving short words, a team decoding race, and a math link through the Morse code tree. You need a printed Morse chart for each pair, paper, pencils and desks to tap on.
The timings are a guide. With younger classes, spend longer on the rhythm and the pairs; with older ones, spend longer on the tree and the counting.
What you need and what students will learn
Materials
- A Morse chart for each pair, with letters and figures.
- A blank Morse tree for each student, or one drawn on the board.
- Paper, pencils and a timer.
- Optional: a few flashlights for the pairs activity, and a speaker to play Morse to the room.
By the end of the lesson, students can:
- explain that Morse is made of short signals, long signals and silences, and that the silences carry meaning;
- send and receive a three-letter word with a partner;
- decode a short message with a chart;
- explain why E and T have the shortest codes, and how many patterns there are of each length.
The lesson fits history, math, computing or music.
The plan at a glance
| Time | Activity | What students do |
|---|---|---|
| 0 to 5 min | Hook | Hear the 1844 story and answer a question |
| 5 to 15 min | Timing as rhythm | Hum and tap dits, dahs and gaps |
| 15 to 30 min | Pairs | Send and receive words, back to back |
| 30 to 40 min | Decoding race | Teams decode messages from the board |
| 40 to 50 min | The tree | Find letters by path and count patterns |
| 50 to 55 min | Exit ticket | Initials in Morse and one question |
Step 1: the hook (5 minutes)
Tell the story in two minutes. On 24 May 1844, Samuel Morse sent a message from the Capitol in Washington along a wire to his partner Alfred Vail in Baltimore: “What hath God wrought”, a line from the Bible (Numbers 23:23) chosen by Annie Ellsworth. He and Vail developed the electric telegraph in the 1830s and 1840s.
Then ask the class: a wire can do only two things, carry a current or not. How would you send words along it? Take ideas for a minute, then steer toward short and long signals with silences between them.
Finish the hook with one detail: the first telegraph receivers marked dots and dashes on a moving paper tape, but operators soon learned to read the clicks by ear. That is what the class is about to try.
Step 2: timing as rhythm (10 minutes)
Put the five lengths on the board. Everything in Morse is measured in units, and a unit is the length of a dit:
| Part | Length |
|---|---|
| Dit | 1 unit |
| Dah | 3 units |
| Gap inside a letter | 1 unit |
| Gap between letters | 3 units |
| Gap between words | 7 units |
Tap a steady beat with a pen and have the class hum along: a dit is one beat of humming, a dah three beats, and the silences are counted in beats too. Then teach letters as rhythm words, a common way to say them out loud: E is “dit”, T is “dah”, A is di-dah, N is dah-dit, S is di-di-dit and O is dah-dah-dah.
Now show why the silences matter. Hum A, wait three beats, then hum N. Then do it again with only a one-beat wait. The class hears .--., which is P. A gap that is too short does not make the message sloppy; it changes the letter.
For a quick class, add SOS. It is sent as one continuous pattern, ...---..., nine elements with no letter gaps, and the letters do not stand for anything.
Step 3: sending and receiving in pairs (15 minutes)
Seat pairs back to back so the receiver cannot see the sender’s hands.
- The sender picks a three-letter word from a list on the board and sends it: humming, or tapping a pencil for a dit and dragging it along the desk for a dah. Flashlights pointed at a wall work too, never at anyone’s eyes.
- The receiver writes down dots and dashes as they come, leaving a space at each letter gap, then decodes with the chart.
- Swap after each word. After four words each, move on to first names.
A word list using only E, T, A, N, I, S and O keeps it manageable: TEA, SEA, EAT, ANT, TEN, NET, SIT, NOT, TIN, NOSE, STONE.
Walk around and listen for letter gaps that are too short. If a receiver writes P where the sender meant AN, ask the pair to work out what happened before you explain it.
Step 4: the decoding race (10 minutes)
Make teams of four. Put a message on the board in Morse; the first team to decode it correctly wins the round. Write it the way Morse is usually written in text, with a space between letters and a slash between words (how to write Morse code in text explains the convention).
| Round | Message in Morse | Answer |
|---|---|---|
| 1 | ... . .- |
SEA |
| 2 | -- --- .-. ... . / -.-. --- -.. . |
MORSE CODE |
| 3 | .-- .... .- - / .... .- - .... / --. --- -.. / .-- .-. --- ..- --. .... - |
WHAT HATH GOD WROUGHT |
Round 3 ties back to the hook. For a tiebreaker, have each team write a short message for another team to decode.
Step 5: the math link, the Morse tree (10 minutes)
Draw the tree on the board. Start at the top: a dit takes you down to the left, a dah down to the right, and every letter sits at the end of its own path. Grouped by length, the letters are:
| Length | Letters |
|---|---|
| 1 element | E ., T - |
| 2 elements | I .., A .-, N -., M -- |
| 3 elements | S ..., U ..-, R .-., W .--, D -.., K -.-, G --., O --- |
| 4 elements | H, V, F, L, P, J, B, X, C, Y, Z, Q |
Questions for the class, with answers:
- How many different patterns have one element? Two? Three? Four? (2, 4, 8 and 16. Each extra element doubles the count, because every pattern can carry on with a dit or a dah.)
- How many patterns of up to four elements are there in all? (2 + 4 + 8 + 16 = 30.) Is that enough for 26 letters? (Yes, with four patterns to spare.)
- The ten figures are all five elements long. How many five-element patterns are there? (32, so ten figures fit easily.)
- Which letters have the shortest codes, and why? (E and T, because they are the most common letters in English, so short codes save time. It is often told that Vail counted the type in a printer’s case to find out which letters were common; treat it as a story to discuss.)
For a computing class, add one more: is Morse binary? Not quite. The sounds come in two lengths, but the silences come in three, and they carry meaning too. The Morse code tree and why E is one dit go further if students want more.
A good follow-up investigation: give each team a paragraph from a book, have them count how often each letter appears, and compare their most common letters with the shortest codes in the table.
Step 6: exit ticket and next lessons (5 minutes)
Exit ticket: write your initials in Morse, and answer in one sentence: why does the gap between letters matter?
Ideas for a second lesson:
- History: the Titanic, 14 to 15 April 1912, whose wireless operators Jack Phillips and Harold Bride sent both CQD and SOS. The Titanic and Morse code covers it.
- Science: wire a battery holder, a push button and an active buzzer (one that sounds by itself on battery power) in a loop to make a working Morse key. Use low-voltage batteries only, and keep it away from wall outlets and household wiring.
- Music: write a message as a rhythm and play it on a drum.
If you teach with a Mac and a projector, Dot & Dash puts a Morse machine on the board: type a message in Write and Send it, and the class hears the tone while a paper tape prints each character. Its Reference plays any letter, figure, punctuation mark or prosign when you rest the pointer on it. Write needs a license after the 24-hour free trial, so use it within the free day or with a license; the machine, the Reference and sharing the tape as an image stay free. The tape image prints each letter under its marks, so use it for a worked example, not the decoding race.
Questions
How long does this Morse code lesson take?
About 50 to 55 minutes as written. For a shorter period, drop the tree section, or split the plan over two lessons with the tree and the history in the second.
Do students need to learn the Morse alphabet first?
No. They use a chart throughout. The aim is to understand how the code works, not to memorize it in one lesson.
Does SOS stand for Save Our Souls?
No. SOS is a single continuous signal, ...---..., and the letters do not stand for anything; “Save Our Souls” is a later reading. It was adopted at the 1906 International Radiotelegraph Convention in Berlin.