1. Module 5

1.18. Lesson 4

Lesson 4

Module 5—Wave Theory of Light

 

Lesson 4—Refraction

 

Get Focused

 

Look very closely at these photos. The drinking straws appear to be disconnected, or shifted horizontally where they exit the water. When the straws are removed from the water, they are straight.

 

Try this now if you have a clear glass and some water. Partially submerge various objects. You will find that any partially submerged object will appear to disconnect or shift at the water line.

 

A photograph shows a clear glass of water with two tall straws standing in it. Refraction causes these partially submerged objects to appear broken or disconnected.

© Adam Gryko /shutterstock

A photograph shows a close-up image of a straw where it enters the water. It looks disconnected at the surface of the water—the top part of the straw does not line up with the bottom part.

© cheyennezj /shutterstock


 

This visual effect is caused by refraction, a process that occurs as light, or any other form of EMR, passes from one medium to another. In this example the light reflected from the straw passes from water into air, where you observe refraction. As light moves from the water into the air, it undergoes refraction, which is a change in its direction.

 

In this lesson you will answer the following essential questions:

  • What is the cause of refraction?
  • What is an index of refraction, and how does Snell’s Law use it to describe refraction mathematically?
  • What is total internal reflection? How does it relate to the critical angle?
  • How does a prism produce a rainbow, and how is a prism similar to a natural rainbow?
Module 5: Lesson 4 Assignment

 

Your teacher-marked Module 5: Lesson 4 Assignment requires you to submit responses to the following:

  • Laboratory—LAB 1, LAB 2, LAB 3, LAB 4, LAB 5, LAB 6, and LAB 7

The other questions in this lesson are not marked by the teacher; however, you should still answer these questions. The Self-Check and Try This questions are placed in this lesson to help you review important information and build key concepts that may be applied in future lessons.

 

After a discussion with your teacher, you must decide what to do with the questions that are not part of your assignment. For example, you may decide to submit to your teacher the responses to Try This questions that are not marked. You should record the answers to all the questions in this lesson and place those answers in your course folder.