2. Goals
• Students know visible light is a small band within a very broad
electromagnetic spectrum.
• Students know that for an object to be seen, light emitted by or
scattered from it must be detected by the eye.
• Students know light travels in straight lines if the medium it travels
through does not change.
• Students know how simple lenses are used in a magnifying glass,
the eye, a camera, a telescope, and a microscope.
• Students know that white light is a mixture of many wavelengths
(colors) and that retinal cells react differently to different
wavelengths.
• Students know light can be reflected, refracted, transmitted, and
absorbed by matter.
• Students know the angle of reflection of a light beam is equal to the
angle of incidence.
16. Your eye movements make this design seem to shimmer.
You can get a stronger shimmer effect by moving your head as you stare at the design.
The motion you see is not in the design, but in your own eye. Even though you're not
aware of it, your eyes are constantly making small, jittering movements, which continually
refresh the image cast on the back of your eye. Normally, your brain can ignore this
motion, so your picture of the world stays stable.
Each time your eye moves, the old image is briefly superimposed on the new image in
your eye. When your eye moves over the repeating, evenly spaced lines of this design,
the old and new images are superimposed to create a swirling shimmer.
