The phosphorescence of many objects, chemicals, and products emits light. The glowing of some critters serves a purpose, such as fireflies, which attract mates and deter predators. Radium is an example of a radioactive substance that glows as it decays. On the other hand, tonic water can be made to glow.
Some of the most famous things that glow at night are:
A firefly’s light attracts mates and also attracts predators who associate it with a tasty meal. A chemical reaction between luciferin, a compound produced in the insect’s tail, and oxygen causes the glow.
Radium decays into a pale blue color as it decays. Self-luminous paints, which are typically green, use this compound most commonly. A paint’s phosphor is illuminated by the energy provided by the decay of radium, not by the radium itself.
Plutonium is one of the radioactive materials that glows, but not all radioactive elements glow. Upon reacting with oxygen in the air, the element glows a deep red, like an ember in the flame. Rather than emitting radiation, plutonium essentially burns in the air, so the metal glows. Pyrophoria is the term used to describe it.
Chemical reactions or chemiluminescence cause glowsticks or lightsticks to emit light. Generally, energy is evolved and then used to excite a fluorescent dye in a two-part reaction.
Bioluminescence is often observed in jellyfish and related species. In addition, some species contain fluorescent proteins that glow when exposed to ultraviolet light.
A type of bioluminescence exhibited by some fungi is fox fire. It is most common for fox fire to glow green, but some species may emit a red glow.
As with plutonium, phosphorus glows when it reacts with oxygen in the air. An eerie green glow emanates from phosphorus and phosphorus. Radioactivity is not associated with phosphorus, even though it glows.
Regular and diet tonic water contain a chemical called quinine, which glows bright blue when exposed to black light.
To make bleached paper appear brighter, whitening agents are added. The whiteners make white paper appear blue under ultraviolet light, even though you never see them.
Certain papers are marked with fluorescent dyes that appear only under certain lighting conditions. A good example is a banknote. You can find out more about one by looking at it under a black light or fluorescent light.
It emits a greenish light and is an isotope of hydrogen. Tritium is found in some self-luminous paints and gun sights.
At room temperature, radon is a colorless gas, but when cooled, it becomes phosphorescent. When radon’s temperature is lowered, its color deepens, turning orange-red at freezing.
Jellyfish and corals are related. The coral glows either naturally or when exposed to ultraviolet light. Green glow-in-the-dark products are the most common, but there are also red, orange, and other colors available.