Light• Objects can absorb

light, reflect light, and allow light to pass through them.

• The type of matter in an object determines the amount of light it absorbs, reflects, and transmits.

Opaque

• Objects that are opaque only absorbs and reflects light – no light passes through it.

• My walls are opaque as is this beehive.

Transparent• Translucent materials

transmit almost all of the light that strikes them.

Translucent

• Translucent objects allow some light to pass through them but you can not see through them perfectly.

• Curtains and frosted glass are translucent.

Law of Reflection

• The Law of Reflection states that whatever angle the light wave strikes a surface, the light wave will be reflected at that same angle.

Question• Why can you see

your reflection on a smooth marble floor and not a brick building?

Answer

• Rough surfaces like brick walls…..cause diffuse reflection which is when the uneven surface causes incoming parallel light waves to be reflected in many different directions.

Refraction

• Refraction is caused by a change in the speed of the wave when it passes from one material (medium) to another.

Index of Refraction

• A property of the material that indicates how much it reduces the speed of light (how much it makes the light bend).

• If Index of Refraction is a big number, the more the light is slowed down…

• Eyeglasses, binoculars, cameras, and microscopes use refraction.

Prisms

• The triangular prism refracts the light twice (once when it enters and again when it leaves the prism.)

• Because the longer wavelengths of light are refracted less than the shorter wavelengths, red light is bent the least and the colors seem to separate out.

Rainbows

• Rain drops also refract light just like prisms.

• The refraction of the different wavelengths can cause white light from the sun to separate into different colors (red, orange, yellow, green, blue, indigo, and violet.)

Mirages

• A mirage is an image of a distant object produced by the refraction of light through air layers of different densities.