Codes: lights, signs and words
To send information, your senses gather it from the world and your brain makes sense of it. Many messages travel in codes. A code is a set of signals or symbols that people have agreed on. A thumbs up means “good”. A red traffic light means “stop”. A smile or a frown shows how someone feels. Languages and writing are also codes: the letters of Arabic and English stand for sounds. A lighthouse sends flashes to ships, and dots and dashes can be used for light or sound signals: a dot is short, a dash is long. A code works only if the sender and the receiver both know the meaning. Here is our own make-believe code for a torch: one short flash means yes, two short flashes mean no, one long flash means come here, and short then long means I need help. Use only make-believe messages and never share real names or passwords.
| Torch signal | Meaning |
|---|---|
| • | yes |
| • • | no |
| — | come here |
| • — | I need help |
Torch code. In a dim room, with a grown-up, sit across from a partner. Use the table. Send five make-believe messages with the torch, one at a time, pointing it at the floor or the wall, never at faces. The partner writes what they think each message means. Check together. How many were right? Try again with claps for dots and a long hum for dashes.