Asked by: John Awbery, Reading
The human eye is less sensitive to longer wavelengths, so red light is chosen to preserve the night vision of the crew while still allowing them to still see their instrument panels.
Submarines switch to red light when it’s dark outside and crew members need to use the periscope or go on watch duty.
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Authors
Robert is a science writer and visiting professor of science at Aston University. He likes maths, West End musicals and hamsters.
