Sunglasses at Night

Honors Physics investigated the inverse-square nature of wave intensity/source distance to very good result. Added on was a study of how well sunglasses reduce light intensity. It was quickly apparent that some types of sunglasses do a much better job at reducing the amount of sunlight that reaches the eye. This experiment did not include a side dish of polarization; we will conduct a separate lab investigation on polarization at the end of the chapter. G block added an extra component to the lab that targeted sunglasses ability to block UV rays. An apology to C block, who did not conduct this part of the lab as I had forgotten that I had gotten a free sample of UV-sensitive beads thrown in with a purchase until I ran across them at lunchtime. Today, UV protection is standard for sunglasses and all the tested pairs blocked the UV rays from the test beads. Older sunglasses might likely not block the UV, however, so take care when purchasing vintage sunglasses that you actually plan to wear outdoors.

Physics discusses the nature and models of light. Tomorrow, you will conduct the intensity lab and are reminded to bring a pair of sunglasses with you to class tomorrow. We went deeper into the particle model of light than does your textbook in this chapter and don't forget this when test time comes around.

Physical Science completed their discussion of sound and light with an overview of lenses and the phenomenon of dispersion. We will review the last of the homework problems tomorrow before engaging in a general review of the chapter. The test of Friday will be longer than normal due to the fewer number of math problems. The only formulas we worked with in this chapter were the wave speed formula, the intensity formula and the lensmaker's equation (from the lab. The law of reflection does not really count as a formula, so I'll won't put it on the list. There is a lot of material in this chapter, so I hope that no one leaves their studying until the last minute. Monday - we begin our unit on electricity.

Today's discussion of rainbows brought up the concept of moonbows:



Here is another interesting formation- the double rainbow. Note the color order of each member of the pair: