Wonder how glow-in-the-dark stars work?

I was going through my son’s toys today and ran into a box of glow-in-the-dark stars I forgot about. I used to love them when I was a little girl, my ceiling was covered in them. So I started wondering- what makes them work? I don’t remember learning that in school.

The following is an article I found online that explains them:

Fun With Photons

1. Glow-in-the-dark stars adorn the bedrooms of many children. These decorations add fun and interest to many rooms and can be a great way to spark a child’s imagination. While many items glow in the dark because of radioactive paint, these stars do not work in quite the same way as many similar such products.

   The key to understanding how glow-in-the-dark stars operate lies in having a basic understanding of light particles called photons. The human eye, which is sensitive to light, sees the light particles that these stars release. (When light is absent entirely, you cannot see.)

How Do Glow-in-the-Dark Stars Give Off Light?

2. When the lights in a room where glow-in-the-dark stars are placed are off, the stars themselves are capable of giving off light. The technical term for this is “photo-luminescent.” The material shoots out stored-up photons that the stars were exposed to during the course of a day. As long as the glow-in-the-dark stars have photons stored, they will continue to give off light. When the material releases all the photons it has stored, it needs to be recharged.

How Do Glow-in-the-Dark Stars Store Photons?

3. Most objects do not store photons in this way. As soon as light hits the object, the photons are bounced back to our eyes or absorbed. We see the wavelengths that get reflected. As noted above, not every object behaves in this manner. The glow-in-the-dark stars can store some of the photons absorbed by them for later use. As long as light hits glow-in-the-dark stars, they continue to store photons for later use. The reader should think of these stars as being able to store light energy in the same way a rechargeable battery can store electricity.

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