We observed that when light ray travels from air to the plastic rectangular block, it bends towards the normal. This is because the light travels from a less dense medium to a denser medium. When the light ray travels from plastic to air, the light bends to its normal angle which is away from the medium. This is because the light moves from a denser medium to a less dense medium. We also observed that at angle 90 degrees, there is no refraction.
We observed that the ray of light when at 10 to around 40 degrees, there is a refraction and a very weak reflection of rays
However, at around 43degrees, there was no angle of refraction. This is known as critical angle whereby if the incident angle were to increase and bends away from the normal, there will no longer be a ray of refraction.