The two talks below at AAPT Summer 2013 have motivated me to re-think what kinds of questions I should ask students to consider online.
First, I should say
I think we don’t have a very good text for my intro physics course. Students are expected to read the text before class, and the typical way things go is students have a 5 MC quiz when they walk in the door. My strategy has been to have students answer questions online before class (graded for effort), and then use low-stakes standards-based grading quizzes which students can reassess on.
Because of the bad text, previously, my goal had been to use the online quizzes to introduce questions, exercises, and links to external resources to supplement the text with good stuff the text lacked. Now my goal has switched a bit toward helpings students engage with the text more meaningfully (even if it isn’t great). My hope is to get students engaged back with the text, and to make reading strategies explicit both in and outside the classroom. Each of the strategies below I hope to practice with students in class before introducing to students in the online reading quizzes.
One thing this exercise has forced me to do is actually read the text carefully, and look for opportunities for students to engage.
Right now I’m considering how much autonomy to give students, and whether and how I’m going to let students decide later on what sentences, equations, etc to interrogate. That would be the goal, right? For them to monitor their own understanding, and decide where to put forth the effort to “dig deeper”.
Anyway, here are some of the things I’m considering, with an example to help illustrate it. Feedback, suggestions comments, criticisms, questions welcome.
Interrogate a Sentence
On pg. 20 the text reads, “The slope of the position vs. time graph gives us the average velocity of the object under consideration.”
Explain why this sentence is true?
Interrogate an Equation
Equation 3.2 on page 25 defines “average acceleration in the x-direction”.
Imagine you are driving a car along a long straight road, and then you begin to speed up. Explain how you could use the car’s speedometer and a stopwatch to determine the car’s average acceleration. Why does that procedure make sense in terms of the definition provided?
Perform a Home Experiment
Part I: First, go find a friend or family member. Next, get a piece of paper and a textbook. Discuss with your friend what will happen when you drop the piece of paper and textbook from the same height at the same time. Which will hit first? Be sure to explain why you think so to each other. Do it and see what happens.
Part II: Now crumple up the piece of paper. You are going to repeat the experiment again with the crumpled paper, but before you do so, discuss with your friend what you both think are going to happen and why.
Part III: Finally, grab various objects and have fun dropping them–tissue plastic bottles, paper, pencils, coins, dollar bills, rocks, baseballs, whatever. Drop them from various heights if you want. Don’t break anything that shouldn’t be and don’t hurt anyone.
Based on the text’s definition of “free-fall” (read the 2nd paragraph) which objects do you think underwent free-fall motion? Which one’s would you say did not undergo free fall motion? Explain how you used the definition to help you decide. Under what conditions will two objects dropped from the same height at the same time hit the ground at the same time? When will they not?
Test Your Skills
You are driving your car along a straight and narrow road, while maintaining a constant speed of 60 mph. Above, an airplane flies with a constant velocity of 500 mph. Which of the following statements best characterizes how the car’s acceleration compares to the plane’s acceleration?
- The car has a greater acceleration than the airplane
- The airplane has a greater acceleration than the car
- Both the airplane and the car have the same acceleration
- It’s impossible to tell how the accelerations compare from the information above.
Explore Your Commonsense
On page 41 of the text, the author writes, “Here’s an extra question for you to think about (one that people usually get wrong!): In the previous example, what was the acceleration of the rock the instant it reached the very top of its motion? If you think the answer is zero, you’d better think again!”
(a) First off, the author has clued us in that the acceleration is not zero at the top, but let’s play along. Intuitively, why does it make sense to think that the acceleration at the top is zero? What reasoning might a person give who thinks it’s zero?
(b) You Choose: Either write down an idea you have about why the acceleration cannot be zero at the top OR write down one question you’d like to discuss in class about the acceleration of a ball in free-fall.