1. The Cause of Refraction
What is light? What happens when light hits an object? Why does light refract? What causes this behavior? Why is there one angle of incidence at which no refraction occurs? What is this angle? Does refractive behavior always occur?
Explore answers to these questions by following the links below.
Consider This Before Answering the Questions
The text discusses what happens when light deviates from its original path because of a speed change, or refraction.
Go to http://www.howstuffworks.com/light.htm to check out first, how light works, and then you will move on to explore refraction a bit more in depth. So, at the first site, read the article "When Light Hits an Object," http://www.howstuffworks.com/light5.htm so you can explain the four things that can happen when that occurs. The next part of this exercise is a little tricky: After you've read this first article, scroll down to the last link, "Lots More Information," click on that http://www.howstuffworks.com/light7.htm then scroll down to "The Light Around Us" and then to "The Mathematics of Refraction," http://www.howstuffworks.com/framed.htm?parent=light.htm& which you can save for another lesson. From here, click on the link on the left-hand menu, "Boundary Behavior" http://www.howstuffworks.com/framed.htm?parent=light.htm& Whew-you've arrived! Read Lesson 1 on "Refraction at a Boundary," and check out the animation. Then, as you continue to read, answer the questions that are posed before you read the explanations. When you've finished reading this section, click on the third link on the left menu, "The Cause of Refraction" http://www.howstuffworks.com/framed.htm?parent=light.htm& Paragraph two begins with three questions that it then answers with an example somewhat similar to the one in the text: Why does light refract, what causes this behavior, and why is there one exception to the refraction (what is that exception?)? The next question asks if refractive behavior always occurs. Explain why it doesn't. Check out the animation, and then explain why refraction occurs. After You Answer the Questions
Now, considering what you've learned, see if you can come up with some practical (or not-so-practical) applications of this information in your own life. For example, how can you use this to make life a bit more fun-or, perhaps, when you decide to select an engagement ring?
2. Let's Wish on a Rainbow
Have you ever wondered about the "physics" of a rainbow? Have you ever wondered exactly what it is? What will affect whether you see a rainbow (or two)? What do dispersion, refraction, and reflection have to do with rainbows?
Follow the links below to learn more about rainbows.
Consider This Before Answering the Questions
Notice in the text how rainbows are related to what you've learned about refraction and dispersion of light.
Now, link to http://www.phy.ntnu.edu.tw/java/Rainbow/rainbow.html to play around a bit with the "physics" of a rainbow. (Note that the second paragraph refers to a "black circle," but on my screen and printout it was white-the rest of the graphics worked well.) As you play around with the lines and the colors, notice what changes occur. What are some of the things that might happen to the light? Do drag the rays around and click inside the colored (and white) boxes to see what happens. After You Answer the Questions
You can find another good explanation of rainbows at
http://www.howstuffworks.com/question41.htm .
