why do they do that
In: Earth Science
A lighthouse does not actually have a very bright light on them. Early lighthouses might have been powered by candles, later improved with oil lamps. But even today some lighthouses are battery powered and have to conserve their power which limits the power of the light. The trick with a lighthouse and why they are able to get a tiny light to be so visible is that they have a big lense and reflectors which focus all the light in one single direction. This can make even the tiny amount of light from a candle visible for miles. The issue is that doing this makes the light invisible from all other angles. So a lighthouse have to constantly move the lens around to focus the light at different parts of the ocean so that all the ships will be able to see it. From a ships perspective a lighthouse looks like it is blinking. This also have several adavantages. Different lighthouses have different patterns of lights and different speeds so it is possible to identify a lighthouse just by looking at its light. It is also possible to set up the lights to help sailors find out where they are. So this feature have been retained even with more modern lighthouses.
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