Sending Messages With Light and Sound
- Physics
- Ages 6–8 · Grades 1–2
- Hands-on experiment
What you’ll find out
- Light and sound can carry messages over a distance.
- People agree on a code, such as flashes or beats, so the message makes sense.
- Some signals work better in the dark, and some in fog.
No sign-up and no real names. In the lesson you check your understanding as you read, run the experiment yourself, and practise until it sticks.
Signals you can see and hear
How can you send a message to someone far away without shouting? You can use light or sound. Flash a torch on and off, or bang a drum, or blow a whistle. Long ago, people sent news with drums, horns and smoke. Today, a lighthouse flashes its light to warn ships about rocks, even far out at sea.
Agree on a code
Flashes and beats only make sense if everyone agrees what they mean. This is called a code. You and a friend might agree that one flash means yes and two flashes mean no. Then you can talk across a dark garden! Light is easy to see at night, but in thick fog it is hard to see. That is why ships blow loud horns in fog.
Curriculum links: NGSS 1-PS4-4