How does light house work?

Question

I keep reading that lighthouses help sailors 1) be aware of dangers like rocks and reefs, and 2) navigate in the dark. I understand that lighthouses beam a series of flashes that a sailor can see from far away, but I’m not quite sure how seeing a series of flashes in the dark from a single point-source can accomplish point 1 and point 2.

In: 8

Answer 1

The gap between each flash identifies which lighthouse it is, knowing what the lighthouse is tells the sailors where they need to sail and how much space to give the danger.