We discussed how to compose our lab reports for the refraction of light.
Assignment: Ch 23 P: 7, 9, 11, 13, 15 Our plots of the angle of refraction plotted against the angle of incidence were pretty straight but maybe with a bit of a declining slope as the angle of incidence got larger. In any case, it was pretty straight, so I introduced the finding of Willebrord Snell, who found a very linear relationship we now call Snell's Law: Here n1 and n2 are the "indices of refraction" of medium 1 and medium 2, respectively. 𝜃1 and 𝜃2 are the angles of the light ray in medium 1 and medium 2, respectively. Don't forget that we measure angles with respect to the normal to the point on the surface between the two media at which the light ray falls.
DRAWING RAY DIAGRAMS: We collected data to find out how the angle of refraction depends on the angle of incidence using lasers and glass blocks.
The challenge that we now confront is coordination of our understanding of ray diagrams with what we see with out eyes when we look at mirror images. While virtual images are more familiar and probably easier to make sense of in a ray diagram, real images can be striking, and surprising; real images are in front of the mirror and are really there in space! We hope to see this with a new mirror that we should be receiving in the next couple of days.
Our main effort today was to understand why we do ray diagrams for curved mirrors and what they can tell us. In one way, ray diagrams are simple, but interpreting them to get the whole story is more involved. And so we will work to make the story clear this week.
Assignment: 03ch23assignment03.pdf We focused on flat mirrors and mirrors that have foci! Our task is to find out what happens to light that strikes a mirror such that we see an image of something in that mirror. The key is to understand how we see objects where we do. If we understand how we locate objects with our visual system, it is easy to understand how mirrors allow us to see images of objects.
An image is seen at a location from which light rays come in a way similar to how they come from the object itself. In our work we actually find the location of the image of a single point of an object. Light rays stream away from any and every point on an object that we can see. They will be seen to stream away from image points in a way similar to how they stream away from the corresponding object points. Assignment: Flat mirrors We reviewed Chapter 22 for tomorrow's quiz by going through the chapter objectives. After that, we looked at another kind of wave, gravitational waves, and how they are detected. It's pretty amazing, but when black holes merge, an enormous amount of gravitational energy is lost from the black hole system and is carried away by gravitational waves. It is impressive that we can observe them. Here are the videos we saw: Assignment:
Prepare for tomorrow's Ch 22 Quiz. |
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