Glowing places…what is the science behind glow-in-the-dark?

Glow-in-the-dark gadgets used to be peculiar and exciting toys for children, as they attempt to understand the eerie green glow emanating from their favourite toys. From glow in the dark yoyos to clothing, glow sticks, home decorations and even paint, glow-in-the-dark technology can now be found everywhere. It is now an essential component of festival-goers outfits and teenage parties.

The science behind glow-in-the-dark products lies in their chemical components called phosphors. Phosphors radiate the recognisable green glow once they have been charged by exposure to light. Glowing products can be separated into different types: chemiluminescence (e.g. glow sticks), radioluminescence (e.g. clocks), bioluminescence (e.g. glow worms) and phosphorescence (e.g. toys).

Whilst common glow-in-the-dark gadgets need to be ‘charged’ in bright light before revealing their glow, some products, such as glow sticks, work due to a chemical reaction emitting light. This is called ‘chemiluminescence’. When a glow stick is snapped in half, the chemicals inside react with one other, resulting in a coloured glow.

Alternatively, for a long-lasting glow required on items such as clock hands and timepieces, designers use ‘radioluminescence’, which is the result of a small amount of radioactive material (e.g. radium) added to the product to constantly charge the phosphors.
Naturally occurring- animals and landscape.

However, not all glow-in-the-dark items are man-made. In some parts of the world and animal kingdom, a luminous glow is naturally-occurring.

The eyes of some mammals, including cats and raccoons appear to glow in the dark at night. However, the reason for this is simply a layer of reflective tissue behind the retina which reflects light. This layer is called ‘tapetum lucidum’.

Probably the most well-known glowing creature is the glow worm. Known for little else other than their luminous appearance, glow worms emit a green glow through different organs in their bodies. ‘Glow worms’ does not describe a single species but is instead the term for different families of insects with glowing abilities. These include phengodidae and lampyridae.

The purpose of the natural glow varies from attracting a male mate, to warning to potential predators and attracting prey.

In Puerto Rico, the waters of Mosquito Bay on the island of Vieques emit an eerie luminous glow as a result of millions of microscopic organisms beneath the surface. These organisms are called Dinoflagellates and are a type of plankton. Their natural glow is triggered by movement in the water.

Here are some glow in the dark gadgets you might not expect…

If the mysterious green glow appeals to you, here are some unusual household products now available with glow-in-the-dark technology.
Toilet paper: it may seem bizarre but it is possible to buy luminous paper for dark nights.

Wallpaper: whether you would want glowing walls is a matter of personal preference, but for those who do, it is possible to decorate your home with glow-in-the-dark wall-coverings for an eerie, cosmic glow.

Headphones: specifically designed for joggers on late night workouts, glow-in-the-dark headphones are ideal for improving runners’ visibility on the roads. Alternatively, glow-in-the-dark bicycles are a great way to stay safe on the road at night.

Doormat: For those dark nights when you stumble over the doorstep, a glowing doormat could be the ideal solution.

Light switch covers: It may seem trivial, but how many times have you walked into a room and spent five minutes fumbling for the light switch? This could provide the ideal solution.

The writer of this post: Victoria is a writer for Direct Sight, online supplier of prescription glasses.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.