GoalTell how people sent messages long ago, read a simple Morse code of dots and dashes, and give step commands in a code.
New words
Morse code · a code of short signals (dots) and long signals (dashes)command · an order that tells someone what to dorepeat · to do the same thing again
Explanation
Long ago, before phones, people found ways to send messages far away. They lit fires to make smoke signals, beat drums and sent riders. Some people used pigeons to carry small notes. In the 1800s the telegraph sent messages along wires as short and long clicks. The code for these clicks is called Morse code. A short signal is a dot and a long signal is a dash. Each number and letter has its own pattern of dots and dashes. We can send Morse with a torch or by tapping. A code can also give steps. A friend or a robot can follow commands such as forward and turn right. When the same step comes again and again, we use repeat to make the code shorter.
Number
Code
1
• — — — —
2
• • — — —
3
• • • — —
4
• • • • —
5
• • • • •
Worked examples
A tower makes smoke. The next tower sees it and lights its own fire. In this way a message travels far.
Flashes
Number
• • • — —
3
Jana flashes a torch: short, short, short, long, long. She is sending the number 3.
Seif’s robot starts at the bottom left and faces up. His code is: forward, forward, turn right, forward. The robot goes up two squares, turns, and goes one square.
Class activity
Send a code. With a grown-up, use a torch to send a number from 1 to 5 to a partner: a short flash for a dot and a long flash for a dash. Never shine the light into anyone’s eyes. Then play robot: one child gives commands such as forward, forward, turn right; the other walks. Use “repeat” to make the code shorter.
Practice
1
Name two ways people sent messages long ago.
Any two: smoke or fire signals, drums, riders, pigeons, the telegraph.
2
What are the two kinds of signals in Morse code?
Dots, which are short, and dashes, which are long.
3
Read the code. Which number is it? Use the table in the lesson.
Code
Number
• • • • —
?
4.
4
The robot starts at the bottom left and faces up. Which commands make this path? A forward, forward, right, forward, forward. B forward, right, forward, forward.
