Understanding light through the particle and wave theory

Light does not appear to bend. Sound can go through crooked pipes, but light is not known to follow crooked bends. However, when light passes through water, the angels of incidence and refraction differ.

• Newton proposed that light's velocity in water was faster than in air. Once they enter water, the corpuscles were acted upon by a force that increased their velocity and changed the direction of the light. But Newton was not convincing as he could not explain the nature of this force.
• Huygens assumed light travelled slower in water and used his undulatory theory in a simple way.