Lectures don't really work. Here's something that does.

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When I started college I wanted to be a math major. Then I hit my sophomore year. I took two math classes and physics and I felt like I was being thrown on the ground and kicked in the head with an iron boot.

By the end, I don't think my physics teacher even recognized me. I went to maybe two lectures second semester. Of course, once I lost the thread, I was in trouble. I wasn't wise enough to get help.

It turns out that missing lectures might not have been hurting me. (I wasn't reading the book either, I was just doing problem sets. I'm not proud.)

Lectures don't accomplish nearly as much as teachers and students think. At least, so says this fascinating NPR story about physics lectures. Every teacher should read it.

The problem with lecturesBooks do a good job of communicating the physics concepts. Let the books do their job. Lectures should do something else.

What should lecturers do? One option is to cover information that's not in the book. But a plethora of research shows that students retain far, far less than college professors (like me) think. So this isn't a great option.

The best way to learn is to be actively involved in your learning. To succeed you have to struggle, fail at first, and learn from your mistakes.

Instead of lecturing to the class, some innovative physics teachers have students get into groups and work on problems. Then the teacher interrupts to help, and then the students work some more.

They aren't just any problems. Physics students tend to be good at memorizing formulas but bad at understanding them. They know F = MA, and on earth gravity = 9.81 m/s

^{2}. But they don't know that two balls dropped from the same height fall at the same rate, regardless of weight, because they don't understand what the formulas mean.So the teachers ask conceptual questions. And there's more: The questions are really hard. The students can't get them at first, but they struggle until they do. They are asked to fail--which is rare in American education--so they can struggle, and struggle so they can learn.

Teachers and students find this approach disquieting because it's so different. But it is amazingly effective. Students learn three times (!) more when lecturers don't lecture.

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