Most of the artificially made luminous balls are made of fluorescent powder (commonly known as glow powder), which is divided into two categories: photoglow storage powder and luminous powder with radioactivity. Photoglow storage luminous powder is phosphor in the environment after natural light, daylight, ultraviolet light, etc., the light energy stored, after the cessation of light irradiation, in the slow release of fluorescence, so at night or in the dark, can still see the luminous, the duration of a few hours to a dozen hours.