Sir Issac Newton, one of the greatest scientists of all time, developed a fundamental theory about light that is known as the Corpuscular Theory.
According to this theory, light consists of corpuscles which are a stream of discrete, tiny, light and elastic particles that travel in perfectly straight lines in all directions. Every luminous source like the Sun, or a lamp, or a candle, emits these corpuscles. According to this theory, we are able to see different colors because of the difference in sizes of these corpuscles.
the theory also stated that when corpuscles hit a surface,each particle is reflected, and that when light travels from air into water, it will increase in speed. Newton's Corpuscular Theory was important, even though he was wrong on some points. After 100 years of existence, it later gave way to the more popular Christiaan Huygens' Wave Front Theory'.