how does refraction work

Refraction is the bending of a ray of light toward or away from the normal. It occurs when light ray move from one medium to another. The refracted ray will bend away from the normal if the 1^st medium is denser than the 2^nd medium and will bend toward the normal if the 1^st medium is lighter than the 2^nd medium.  According to the snell’s law the ration of the sine of the  incident angle and the reflected angle is the refractive index of the 2^nd medium( provided the 1^st medium is air). The size of the refracted angle is not smaller or larger than the incident angle is called the refracted index of the material ( medium).