The spy pen contains ink that is invisible, which means that under ordinary lighting the ink does not reflect visible light to your eyes. Visible light is one of seven different types of light energy (also called electromagnetic energy) and is the only type of light that you can see. Visible light is a band […]
Fluorescence
Question: What causes some objects to glow under a black light? Black lights give off Ultraviolet A light, which is a type of high-energy invisible light (radiation). Photons are packets of light energy. UV light photons have a higher energy than do the photons for visible light. Materials that glow under a black light contain […]
Fluorescence vs. Photoluminescence
Fluorescence and Photoluminescence are types of luminescence (cold light) where the energy is supplied by EMR (electromagnetic radiation). EMR from most to least energetic are: gamma rays, x-rays, ultraviolet light, visible light, infrared light, microwaves, and radio waves. The starting EMR energy source needed to produce visible light must be more energetic than visible light. […]