1. Different Speeds:
* Light travels slower in glass than in air. This is because the denser material of glass causes the light waves to interact more frequently with the atoms within the glass, slowing it down.
2. Bending of the Path:
* As the light wave enters the glass at an angle, the part of the wave that enters first slows down before the rest of the wave. This difference in speed causes the wavefront to bend, changing its direction.
3. Snell's Law:
* The amount of bending is described by Snell's Law:
* n1 * sin(θ1) = n2 * sin(θ2)
* n1 and n2 are the refractive indices of the two mediums (air and glass).
* θ1 is the angle of incidence (angle between the incoming light ray and the normal to the surface).
* θ2 is the angle of refraction (angle between the refracted light ray and the normal).
4. Key Concepts:
* Angle of Incidence (θ1): The angle between the incoming light ray and the normal to the surface.
* Angle of Refraction (θ2): The angle between the refracted light ray and the normal to the surface.
* Normal: An imaginary line perpendicular to the surface at the point where the light ray enters.
* Refractive Index: A measure of how much a medium slows down light. Higher refractive index means slower speed of light.
Example:
* If you shine a flashlight beam at a 45-degree angle into a block of glass, the light will bend towards the normal (the imaginary line perpendicular to the glass surface) as it enters the glass.
In Summary:
The change in path of a light wave from air into glass is called refraction. This bending occurs because light travels slower in glass than in air, causing the wavefront to bend as it enters the denser medium.
