1. The Speed of Light:
* Light travels at different speeds in different mediums. It travels fastest in a vacuum (like space), and slower in denser materials like water or glass.
* The change in speed is the key to refraction.
2. The Wave Nature of Light:
* Light acts as a wave, with crests and troughs.
* When light enters a denser medium, the wave slows down.
3. The Angle of Incidence:
* The angle at which light strikes the surface of a new medium is called the angle of incidence.
* The angle of incidence is important because it influences how much the light bends.
4. Refraction:
* As the light wave slows down, it also changes direction. This change in direction is called refraction.
* The amount of bending depends on the difference in speed between the two mediums and the angle of incidence.
Think of it like this:
Imagine a car driving from a smooth, open highway onto a rough, muddy field. The car slows down significantly as it enters the mud, and it will change direction slightly as it does.
In the same way, light slows down when it enters a denser medium, and it bends as a result of this change in speed.
Here are some key points to remember about refraction:
* The more the speed of light changes between the two mediums, the more the light bends.
* If the light strikes the surface at a 90-degree angle, it doesn't bend (it just slows down).
* Refraction is responsible for many common optical phenomena, including rainbows, mirages, and the ability of lenses to focus light.
