Codes for letters using binary representation
Children write secret messages by turning letters into numbers and numbers into patterns of on and off.
Steps
- Ask how a computer knows which letter to show. Number the alphabet from 1 to 26.
- Work out the code for one letter together, for example D is 4, which needs the 4 card on and the others off: OFF OFF ON OFF OFF.
- Write the code for your name or a short word, one letter at a time.
- Swap messages with a partner. Decode each other's patterns back into letters.
- Discuss what a computer must also store: capital letters, digits and punctuation, and letters of other languages.
Talk about it
- Why do we need five bits for 26 letters?
- What else would a computer need codes for?
- How could you send your code to someone far away?
CC BY-SA 4.0
Adapted from CS Unplugged by the University of Canterbury Computer Science Education Research Group (CS Unplugged), licensed CC BY-SA 4.0.
Original lesson, with pictures · License: CC BY-SA 4.0
There are no pictures here. The original lesson has the pictures and printables.
Changes made: Simplified, shortened and translated by Open Cosmos with AI
This adapted lesson is shared under the same license (CC BY-SA 4.0).