light rays pass through air & light rays pass through a glass window ->  light rays pass through air and a glass window  glass is a kind of material & a window is made of glass ->  a glass in a glass window is a kind of material  a glass in a glass window is a kind of material & air is a kind of material ->  air and a glass in a glass window are kinds of material  light rays pass through air and a glass window & air and a glass in a glass window are kinds of material ->  light rays passes from the material air through the material glass when it pass through a glass window  medium is made of a kind of material & refraction is when light passes from one medium to another medium ->  refraction is when light passes from one material to another material  light rays passes from the material air through the material glass when it pass through a glass window & refraction is when light passes from one material to another material -> the light rays will refract when they pass through a glass window