We know today that light has wavelike properties. This explains why the rays are bent when they enter the prism. Light slows down when traveling through a medium, as the trough enters the prism before the crest, the bottom part of the wave slows down (before the top) and causes it to bend the ray, which results in the separation of colors, as each color has a different wavelength.
But as Newton believed that light is made of tiny corpuscles/particles, and didn't subscribe to the wave theory, how did he explain the science of refraction? Why does the prism bend the light ray? And more importantly how does white light get separated into different colors?