Double rainbows occur when sunlight is reflected twice inside raindrops, creating a secondary rainbow that appears outside the primary one.

Light refracting and reflecting through a water-filled round-bottom flask makes a rainbow, as light through a raindrop does. A faint secondary rainbow may be visible. The flask has a reflective ...

There are three primary colours of light, which can be combined to make secondary colours. A rainbow contains all the colours of the visible spectrum. It is often possible to see a secondary bow ...

Third and fourth strands of the rainbow are visible - the first two are behind the photographer Only five triple rainbows had been spotted in the last 250 years ...