Fluorescence and Glow in the dark

UV and what it can do.

Uranium glass

Some materials will glow in the dark. There are a couple of mechanisms, one is caused by radioactivity, I do not play with that one. One is caused by chemistry, fireflies and snap lights. Fluorescence is something else. Ultraviolet light which is further into the blue spectrum than blue can cause materials to glow . It excites the atoms and then then they re-emit light at a different colour, almost a light echo but not quite. This is a dish made of vaselein, Czech or otherwise known as Uranium Glass. Not very radioactive (honest) but it glows when you shine UV at it.

Uranium glass marbles Uranium glass marbles, available on line.

I normally use a long wave uv light, a so called black light, this portion of UV is not terribly harmful and is at arround 254 nm wavelength. I also have a UV laser at about the same frequency and that works really well. Shorter wavelength UV can be harmful, it is one of the components of sun light that can cause burns and all sorts of other problems, I have one of those light too but you must be careful.

Jar of Tonic water Flourosceine Tonic water and fluorsceine dye with uv laser.
Colemanite Willemite and calcite Calcite and willemite Minerals, hydrozincite, white. Svarbite, red, Calcite violet, opal, green, and others Many and various minerals glow too.
uv laser on zinc sulphide paper Zinc sulphide is the most common material that is phosporescent. That is it continues to glow after it has been hit with light, most glow in the dark things have some of this in it. Some minerals will do it to, calcite sometimes does.
Glow in the dark Rubber Duck
If you decide to take a black light and look around your house, take care, it makes all the little bits of muck stuck to the cooker light up and it looks awful even if you have just cleaned.