Like bower birds, we humans are entranced by glittery things, which is why we treasure shiny metals, sparkly rocks and we see artificial glitter as festive and pretty. The sight of sun glitters on snow or sea is far more beautiful than artificial glitter but the origin is the same.

Light is electromagnetic waves – travelling energy in the form of vibrating electric and magnetic fields.

 The electromagnetic spectrum in principle is continuous and infinite but the only band we can see is the visible spectrum of light. The electromagnetic bands on either side of the visible spectrum are infrared light and ultraviolet light; these bands may be visible to other species but are not to us.

It is strange to think that no object actually has any colour. Colour is merely a combination of a multitude of reflected frequencies of light waves that are reflected and absorbed by the atoms and molecules on the surface of objects. Our eyes and brain have the ability to process this complex multitude of reflected frequencies into a coherent impression of our environment.

When a stream of light photons, the elementary particles of light, hit an object, the light can be absorbed, transmitted or reflected as the atoms and molecules respond by absorbing and emitting energy. Types of atoms and molecules respond differently, but consistently, to certain light frequencies by changing energy levels.

A mirror reflects light because the angle that a light photon hits and leaves the mirror surface is the same; our eyes perceive this reflected light from one point and at one angle.

If flat snowflakes are resting on a blanket of snow, individual snowflakes at certain angles can act as mirrors that directly reflect the sun’s rays; whether we see glitter depends on the changes in the angle of the sun in relation to the snowflakes' position and the location of our eye. 
 The sun is reflected in a multitude of snowflakes, but different ones will stand out as brighter as the sun and observer change angles.

Artificial glitter is made of tiny reflective particles of aluminium and microplastic, it looks happy and sparkly but it has a dark side – it is a persistent form of pollution, particularly for waterways and oceans. The particles absorb chemicals and pollutants, making them even more toxic as they enter the food chain, where they are mistaken for food by many species.