When learning physics, you pick up math skills. But there's a problem when students only learn how to choose equations and plug in the right numbers. The “plug and chug” questions you see on physics tests are of the easier variety. The hard questions are qualitative and conceptual.
Here is an example of a basic conceptual physics question I saw from NPR.
Two balls are dropped from a building at the same time. Ball A and Ball B are the same size, but Ball A is twice as heavy as Ball B. Which ball hits the ground first?
a) Ball B hits the ground first.
b) Ball A hits the ground first.
c) They hit the ground at the same time.
If you understand Newton's second law (F=ma), you know that both balls hit the ground at the same time.
(Or if you like to guess, you know that c) is always the correct answer)
Even though one ball is heavier than the other, they have the same acceleration, 9.8 m/s/s, so they take the same amount of time to hit the ground.
Even students who have taken physics frequently get this question wrong. NPR reports that lectures are part of the reason students fail to learn the material. Students learn best when they are actively working, not when they passively listen to lectures.
Students do most of the talking in the “Peer Instruction” teaching model developed by Eric Mazur, a physics professor at Harvard. In this model students work together to solve problems in small groups. The professor poses conceptual questions to the students, who respond with answers via mobile devices. If a large percentage of the class answers incorrectly, the students work through the problem in their groups. After discussing with their peers, they answer the question again. The professor exists as a coach guiding the students during practice, rather than as a “sage on stage”.
According to Mazur, the approach works: "What we found over now close to 20 years of using this approach is that the learning gains at the end of the semester nearly triple."
As a physics major, I wish I had taken classes like this when I was in college. Learning through your peers is the best way to learn, especially in science. It also reminds me of an opinion article about science education I read in the LA Times. It referenced a study that sought to explain why some students were more prone to fail first-year calculus at UC Berkeley. The study found that students that never worked with other classmates were the ones that failed, even if they put in the study hours and the effort. The successful students were the ones that studied both by themselves AND in groups, where they helped each other out and figured out exactly where they stood in the class.
One caveat about Peer Instruction: it works best when students come to class prepared (i.e. they have already read through the material). Not all students are going to come to class prepared because many are used to relying on the lectures. As always, the students that go the extra mile and invest their own efforts into learning will get the most out of it.
Also, in this model students answer the same question twice. If only 29% of students answer a question correctly the first time, it sometimes improves to 62% of students who answer correctly the second time. But of course, if you think you answered incorrectly the first time, you can eliminate that answer choice the second time. Odds are that the scores will improve by simply repeating. And I wonder if the students get to see how the class answered overall.
Just some thoughts on group learning.
