Properties of Matter and the Analysis of Glass Properties of Light

Light as a Wave Light can act as a wave that transmits energy through space Light waves are characterized by wavelength and frequency

Electromagnetic Spectrum Light waves travel at the speed of light in a vacuum Types of electromagnetic radiation are distinguished by their frequency, wavelength, and speed.

Dispersion of Light Dispersion – the separation of light into its individual wavelengths. Light waves bend as they pass through a prism; each wavelength is bent to a different degree.

Dispersion of Light

Refraction of Light Refraction – the bending of light waves caused by a change in speed. The speed of light changes as light travels through different mediums When light passes from one medium to another, the change in speed causes light to be refracted

Refraction of Light

Refraction of Light

Refractive Index Like density, each substance has a unique refractive index; it is an intensive physical property Refractive index = speed of light in a vacuum speed of light in a medium The refractive index of water at 25oC is 1.333. The refractive index of a substance depends on its density and it’s temperature; Remember that a substance’s density changes with temperature.

Analysis of Glass The 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.

Analysis of Glass Becke 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.

Analysis of Glass TeacherTube Videos - Refractive index of glass