We did our best to prepare for our Celebration of Knowledge about reflection and refraction today.
An updated Chapter 23 Objective list is here. We will stick to the things we have emphasized in class, so focus (no pun intended) on the Assignments and class discussions. Of course, ray diagrams are essential. Also, do know what kind of lens is used for magnifying glasses and how to position with respect to the lens both the object that you want to magnify and the observer who wants to see the magnified image. We emphasized how rays parallel to the principal axis are affected by converging and diverging lenses and mirrors. Also we emphasized how to calculate the critical angle of incidence for two materials through which light travels. You should know what we mean by 'critical angle.'
We examined our lab results from Monday. You will need to prepare the plot of 1/di vs 1/do, and report the focal length you can find for your lens from the equation for the resulting linear fit. You also need to find the focal length from the image produced when an object is at 'infinity.' For both ways of finding f, report the percent error in your focal lengths. We'll turn these in on Monday after the celebration on Thursday. The Senior play is going to be presented tomorrow, and that will affect many of us. Even so, the test will be on Thursday. Assignments:
While many students were preparing for the upcoming play, the rest of us were playing with lenses. In fact, we used three different methods to find the focal length of a convex lens:
Students presented solutions to problems Ch 23 P: 26-32 today. Our schedule for next week is:
While many of us were heavily involved with Drama, we plugged away with refraction and lenses. Here is a list of items we need to deal with to meet our goals:
Today we got to know Snell's Law, specifically what we mean by the angles of incidence and refraction and by the indexes of refraction. Assignment 6 and Assignment 7 are the way we took to get to know what all these quantities are. We looked at an online resource to help us understand what each variable is, too: Refraction of Light Of special interest were total internal reflection, the squished shape of the sun and moon at rising and setting, and the green flash. We are ready to explore the implications of the refraction of light, described as it is by Snell's Law: We will see how Snell's Law can account for many optical phenomena next week. It's pretty interesting!
Here's a functional simulation from Walter Fendt in Germany: Refraction Here's another simulation from Herr Fendt, and it explains how Snell's Law actually works: Reflection and Refraction explained by a wave model of light. Assignment:
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Physics IIMr. Swackhamer Archives
May 2019
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