Asked by: Beat Furrer, Switzerland
Rainbows are formed when light emerges from water droplets that are in just the right place for the rays to enter our eyes. Such droplets always lie on a circle facing the Sun. Unless we’re airborne we can only see a ‘bow’, as the ground blocks out the rest.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.