Do Now Question: Why/how do you think we see colors? CRO Format 5/11

Why do we see colors Our eyes see light waves with different wavelengths as different colors. Visible light waves with longer wavelengths look red. Shorter wavelengths are a violet color. White light from the sun is a collection of many different wavelengths.

Spectrum of Light In billionths of a meter.

Why do we see colors?

We can separate light using a prism, which is a clear glass or plastic in the shape of a triangle. The band of light coming through a prism is called a spectrum.

Prisms

Why do we see colors? Opaque objects are the color of the light they scatter. We see a yellow banana because all the colors EXCEPT yellow absorb into the banana’s surface, but the yellow color reflects off back to our eyes so we see the banana as yellow. Translucent objects, such as the water container, are the color that goes through it. We see the water jug as blue because that is the only color that goes through it to our eyes.

Why do we see colors?

Warm Up From yesterday’s lesson, what did we learn white light was made up of? Why is an apple red?

Overlapping Colors When light hits an opaque object it either absorbs into it or scatters off of it. These objects appear the color of light they scatter and absorb all the rest. For example: An Orange

Overlapping Colors When light hits a translucent object some colors are absorbed and others pass through. We can only see the light that passes through the translucent object. Example: Water Jug

Overlapping Colors What are the colors on a T.V.? Red, green, blue dots We create any color by mixing in the right amounts. The primary colors are red green blue

Overlapping Colors Look at the picture on page 659 and answer questions 15 and 16. What colors form white light? Equal parts of red, green and blue. Black is created when equal parts of magenta, cyan, and yellow are mixed.

Is all light visible? Define electromagnetism- The way that electric and magnetic forces interact. What are some different forms of electromagnetic radiation? Radio Waves Infrared Waves Ultra-violet Waves The sun can produce all forms of electromagnetic radiation.