What do you see?  Take a piece of aluminum foil and wrap it around the oval top of the card stock.  Make sure the entire oval top piece of card stock is covered with the aluminum foil.  Look at the aluminum foil.  What do you see?

What did you see? When you looked at the aluminum foil, what did you see? Your Reflection!

Essential Question: How does reflection and refraction change how you to see things?  Today, I can describe how reflection and refraction occur.

What is a ? Reflection happens when light waves bounce off an object.  The Law of Reflection states that the angle of incidence is equal to the angle of the reflection.

Types of Reflection There are two types of reflection: 1. Regular Reflection: occurs when light beams are reflected at the same angle. 2. Diffuse Reflection: occurs when light beams reflect at many different angles.

Is it a light source or a reflection?  Most things around you are not light sources. You can see them because light from light sources reflects off the objects and then travels to your eyes. They are illuminated.  You can see a light source even in the dark because its light passes directly into your eyes.  Objects that produce visible light are called luminous. The tail on a firefly is luminous. Flames, light bulbs, and the sun are light sources. Tail on a firefly

Absorption Absorption is the transfer of energy carried b light waves to particles of matter.  The farther the light travels from its source, the more it is absorbed by particles, and the dimmer it becomes.

Scattering Scattering is an interaction of light with matter that causes light to change direction.  Light scatters in all directions after colliding with particles of matter.  Light with shorter wavelengths is scattered more than light with longer wavelengths.

Scattering  Sunlight is made up of many different colors of light, but blue light is scattered more than any other color because it has a very short wavelength. This is why the sky looks blue.

Refraction Refraction is the bending of a wave as the wave passes between two substances in which the speed of the wave differs.

How do objects separate underwater? When you look at an object underwater, it can appear like the object is separated. This is due to refraction. How does this occur?  The light reflected off the object that is underwater does not travel in a straight line.  The light refracts creating an optical illusion that makes the object appear like it has separated.

Refraction  All of the wavelengths of visible light compose white light.  The different wavelengths of visible light are seen by people as different colors  When white light is refracted, the amount that light bends depends on its wavelength.  Waves with shorter wavelengths bend more than those with longer wavelengths.

Color Separation Color separation by refraction is responsible for the formation of rainbows.  Rainbows are created when sunlight is refracted by water droplets. Figure a: Rainbow Figure b: Color from a Prism

Let’s see Refraction in Action! Experiments Rising Coin Bending Pencil Changing Arrow