Compare and contrast how a camera works with how the human eye works. List the mechanical parts that would be similar and the parts that would be different. Describe several different vision irregularities in humans and discuss the various methods that are used to correct them. You can ask your students to contribute to the assessment rubric by determining which structures and what labels should be included in the diagrams. Just an Illusion Students are often amazed at the effects that a simple glass of water can have on light.
Water can actually distort images in some fairly astonishing ways.
To begin this activity, ask your students to drop a penny into a clear, standard-sized beaker of water and then stare at the penny through the side of the beaker. Next, ask them to put a pen or pencil into the beaker, halfway out of the water, and then view it again from the side. The pencil will seem broken, as if the half below the water were unconnected to the half above it. Ask students to speculate about the reasons behind these optical illusions. As light travels through a convex lens, its waves are refracted toward a single focal point.