Reflection and Refraction

When a WAVE encounters a boundary between two materials, it can do one of three things:

1. ABSORPTION:

Here, the wave TRANSFERS its ENERGY to the second material. Often, this turns into THERMAL ENERGY, causing the material to heat up.

For example in a MICROWAVE OVEN the MICROWAVES get ABSORBED by the water molecules in the potato, causing them to VIBRATE and heat up. This THEMAL ENERGY conducts through the rest of the potato, causing its temperature to INCREASE.

2. REFLECTION:  

Reflection occurs when the wave BOUNCES BACK at the boundary of the two media.

The SHINIER an object, the BETTER it reflects visible light.

This allows us to SEE objects. The visible light waves given off by a light source REFLECT off other objects, and enter our eyes.

Ray diagrams include a VIRTUAL line known as the NORMAL which is PERPENDICULAR to the surface of reflection.

The ANGLE OF INCIDENCE is the angle between the SURFACE and the INCIDENT RAY.

The ANGLE OF REFLECTION is the angle between the SURFACE and the REFLECTED RAY.

Whenever reflection occurs on a surface, the ANGLE OF INCIDENCE is EQUAL to the ANGLE OF REFLECTION.

3. TRANSMISSION:

The wave continues to TRAVEL THROUGH the new material. This can lead to another process known as REFRACTION.