Interact with Environment

Transparent Objects: Most of the EM radiation is transmitted (passed) through the object. Very small amounts are absorbed and turned into thermal energy.

Translucent Objects: EM radiation that is the color the object appears to be is transmitted (passed) through. The other colors of light are absorbed and turned into thermal energy. Think about stained glass, is the light coming through ever as bright as clear glass? That is because many of the wavelengths of light are being absorbed and ONLY the colors you see the glass as is being transmitted.

Applet: Color Vision - If you click on the "Single Bulb" tab at the top you can see how light is filtered through translucent objects.

Opaque Objects: Absorb all the colors of light EXCEPT the colors you see, which are reflected back to your eye.

Reflection

Waves hitting a hard, smooth surface bounce off that at the same angle they hit.

Uses: SONAR, RADAR, Echos, Mirros

• Smooth Opaque Objects (mirrors) - The light that is not absorbed is reflected in the same direction giving you the ability to see the image in the object's surface.

• Rough Opaque Objects (the wall) - The light that is not absorbed is diffused (reflected at many different angles) , making an image impossible. The object appears to be whatever color is being reflected (not absorbed).

Refraction

Waves passing from one medium to another bend.

• The wave's speed changes depending on the density of the mediums.
• More Dense: Atoms/molecules are closer together = faster wave travel
• Less Dense: Atoms/molecules are further apart = slower wave travel

Reflection vs. Refraction

Applet: Bending Light (Reflection & Refraction) -Change up the materials you're making light go through and see how the amount of light being reflected and refracted changes, along with the angle of refraction. Make sure you click on the tab labeled "Prism Break".

Why the Sky is Blue:

The light from the sun is white (has all the wavelengths/colors). When it reaches our atmosphere it slows down in the air and is refracted. Blue light bends more than red when refracted, so it is scattered and makes the sky look blue. Red, yellow, and orange light are bent the least, so when you look directly at the sun those are the colors that seem to still be coming from the sun, hence a yellow/orange/red sun.

Diffraction: Waves passing through an opening or around small obstacles.

Speed of Waves

Note: Frequency has NOTHING to do with the speed of a wave! Red and blue light will hit an object at the same time. You will hear high pitched sounds (the violin) and low pitched sounds (the bass) at the same time if they are played together.