Why do lighthouses flash?
For grown-ups: the science
Lighthouses flash so sailors can spot them and tell which lighthouse they are seeing.
Lighthouse lights are often made to appear flashing by rotating optical equipment or shutters that focus and sweep a beam around the horizon. Each aid to navigation can have a distinctive light characteristic, such as its flash timing and color, helping mariners identify it on nautical charts.
What about...?
Ask your child's own question
Transcript
A tall lighthouse stands by the dark, wavy sea. Why does its bright light flash?
A powerful lamp shines from the top of the lighthouse. Its light can travel far across the water.
A turning cover with clear spaces lets the light sweep around. From far away, the light seems to blink.
Each lighthouse has its own flash pattern. Sailors can use the pattern to know which lighthouse they see.
So lighthouses flash to send a clear light signal across the sea. The pattern helps sailors find their way.