6 Refraction of LightRefraction – the bending of light waves caused by a change in speed.The speed of light changes as light travels through different mediumsWhen light passes from one medium to another, the change in speed causes light to be refracted
9 Refractive IndexLike density, each substance has a unique refractive index; it is an intensive physical propertyRefractive index = speed of light in a vacuumspeed of light in a mediumThe refractive index of water at 25oC isThe refractive index of a substance depends on its density and it’s temperature; Remember that a substance’s density changes with temperature.
10 Analysis of GlassThe refractive index can be used to identify glass samples using the immersion method.Glass samples are added to a liquid for which the refractive index can be adjusted. (usually by heating the liquid)When the refractive index of the glass sample equals the refractive index for the liquid, the glass sample will seem to disappear from view.
11 Analysis of GlassBecke line – a halo of light on the outside or inside border of a glass sample immersed in a transparent liquid.When the Becke line disappears, the refractive index of the glass sample matches the liquid.
12 Analysis of GlassTeacherTube Videos - Refractive index of glass