Prism
A prism is a transparent optical element with flat, polished surfaces that refract light. When light enters a prism, it bends or refracts due to the change in the medium's density. The degree of refraction depends on the prism's material and the angle at which the light enters it.
As light passes through the prism, it is separated into its constituent colors, a phenomenon known as dispersion. This occurs because different wavelengths of light travel at different speeds through the prism, causing them to bend at different angles.