How Does It Work
When it comes to glow in the dark, it’s important to know the difference between the two common types of glow, fluorescence and phosphorescence.
Fluorescence – This type of glow occurs when some form of radiation, such as light, causes an object to glow. For example, fluorescent papers and poster boards glow in the daylight. They may seem to glow even brighter under black light (ultraviolet), but in either case, as soon as the light is removed, the glow stops. Fluorescent things do not glow in the dark all by themselves – they require some other form of energy such as ultraviolet light to “excite” them.
Phosphorescence – Phosphorescence is just like fluorescence, except that the glow continues even after the light used to excite it is removed. “Glow in the dark” toys phosphoresce brightly in total darkness after being “charged” or excited by ordinary white or ultraviolet light.
Some highlighters use ink that contains dyes that are fluorescent. When you draw the designs on the circle, it probably looks like those designs will glow when you turn the lights off, but they don’t. The dyes in the highlighter ink require a black light to produce the special glow. You may have found that certain colors of highlighter do not fluoresce underneath the ultraviolet light. These highlighters do not contain fluorescent dyes, but you can get creative with them. Try using them in unison with the fluorescent highlighters to make incredible creations!
