Snow White

Have you ever wondered why snow is white?

Snow by Jeffrey Blum at Unsplash.com

Visible light, as in the light we can see with our eye consists of a rainbow of colours, red, orange, yellow, green, blue, indigo, and violet. When photons of (coloured) light strike an object, they can bounce back, known as reflection, bounce to the sides, scatter; pass right through, referred to as transmission or be completely absorbed which is actually what black is, the absorption of all colours!

Grass is green because it reflects the green light to our eyes and absorbs all the other colors. Red objects reflect red light to our eyes and absorb the (coloured) wavelengths of all the other colours.

spectrum flower by Shaun Pitman at unsplash.com

When light passes through snow, it hits all those ice crystals, and then some of the light comes back out. Snow reflects all the colours, it doesn’t absorb, transmit, or scatter any single color or wavelength more than any other. The colour created by all the light wavelengths combined equally is white, basically this means nothing is retained within the snow, what passes through the flakes is unaffected and they all combine equally to make white!

And there was us just thinking it was white because it is.

Edinburgh in a blanket of snow courtesy of Historic Scotland with thanks.

#snow #white #nocolour #cheyhes #edinburgh