A "discovery exercise" steps through a technique. In the Discovery Exercise on time dilation, a student steps through some simple Galilean calculations to find the speed of a light beam in two different reference frames. This exercise leads students to the classical conclusion that light beams go at different speeds in different reference frames; more importantly, the students themselves put together a seemingly incontrovertible argument showing that light must go at different speeds in different reference frames. So when they read the section or hear in lecture that Einstein's posulated that the speed of light is constant, they are clear on why that postulate can't be easily incorporated into Newtonian physics.
Frequently Asked Questions About Discovery Exercises
At home or in class? Alone or in groups?
Mix it up. See what works for you. We sometimes assign them as homework due on the day we are going to cover the material, and sometimes as an in-class exercise to begin the lecture. You can have students do them individually or in groups, or a mix of the two. One professor we spoke to starts them in class, and then has her students finish them at home—an approach we never even thought of. You will probably keep your students' interest better if you vary your approach.
Do I need to assign all the exercises?
No. If you are uncomfortable with the process, you may want to try only one or two. We hope you will find them easy to use and valuable, and over time you will use them more, but you will probably never use them all.
How long do they take?
Some are five minutes or less. Very few of them should take the students more than 20-30 minutes, and most should take 15 minutes or less.
That was all pretty noncommittal. Do you have any solid advice at all?
Actually, we do. First, we hope you will use at least some of the exercises, because we believe they contribute a valuable part of the learning process. Second, exercises should almost always be used before you introduce a particular topic—not as a follow-up. You can start your lecture by taking questions and finding out where the students got stuck.
If you are using our textbook, some motivated students reading the text before class will pause to try these exercises before reading on. Doing so will greatly improve their understanding and retention of the material. But many students will not do that, and their first introduction to the material will be in your lectures.
So whether or not you are using our book, we would love you to try, just with one or two of these, pausing your lecture at that point. Put a slide up with those questions. Give the students one minute to think about these questions on their own, and then another minute to compare and discuss answers with their neighbors. Research shows that one or two such interruptions, lasting no more than 1-2 minutes each, vastly improve student retention of a 50-minute lecture.
What then? In some cases (as in the example above), the answer is vital to the next steps in the lecture. So you might pick up your lecture by polling the students about their responses and then discussing the right answer. In other cases, the answer to the Active Reading Exercise isn't vital at that point and you can leave it for them to think about as you move on.
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Click here for the home page for the book, http://www.felderbooks.com/modernphysics. |
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If you have questions, we would love to hear from you. Click here to email the authors at GFelder@Smith.edu. |