1. Properties of Matter and the Analysis of Glass
Properties of Light

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

3. 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.

4. 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.

5. Dispersion of Light

6. 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

7. Refraction of Light

8. Refraction of Light

9. 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
The 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 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.

11. 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.

12. Analysis of Glass
TeacherTube Videos - Refractive index of glass