Active Lecturing

Lecturing is said to be a very poor way of teaching.  Lectures provide passive learning, whereas studies indicate that students learn more through active learning, such as working problems in the classroom.  And yet, lecturing is what most teachers do in college classrooms.

Actually, in the classroom lecturing is not as passive as is implied.  Most students take notes.  That requires summarizing the teacher’s words in fewer words.  A problem with laptops in the classroom is that students can copy down words too easily so they lose the need to summarize.  Summarizing is active learning:  the students have to work at it to summarize.  Just copying words down is passive learning; without having to work at it, the new ideas being copied do not stay with the student as well.

Teachers typically add active learning to their lectures in the form of questions.  The teacher may think of a question during the lecture and ask it. Other times, for myself, I think of questions before the lecture and add them into my PowerPoint lecture notes.  To be effective, the questions need to involve applying the concepts just presented. When I ask questions, usually only a few students will answer.  However, looking at the faces and body language, I see that many of the students are thinking about a possible answer.

An effective lecture builds on what the student already knows.  We often start out commenting on previous ideas—sometimes just by reviewing the previous lecture—and then presenting ideas that build on the old.  That approach makes my lectures understandable.

An effective lecture also relates new ideas to people’s lives.  Naturally, I try to relate chemistry to people’s lives.  Here is an example from last semester.

  1. The old information the students build on:  Remind students of how energy is treated.
  2. Intro to what we are about to do.  Tell them that the steps in something dissolving can account for for whether a solution gets warmer or colder when a salt dissolves in it.
  3. The new information.  Go through the process, presenting the new material about  dissolving taking place in steps.
  4. Relate to life.  Apply the new information to account for how cold packs and hot packs work.

Including real world examples as above makes my lectures somewhat interesting.

An effective lecture also motivates students to learn.  Yeah, but how?  After giving the above lecture I realized:  what a wasted opportunity.  I’ve been doing this wrong for twenty years.  Perhaps you can see how the pieces above could be put together to motivate the students.  The last step—the real world example—could have been placed at the beginning to make them wonder, “How does chemistry explain this?”  Like a good movie, make the audience want to know what the answer is.  The next time I present the above material I will add an extra first step.

  1. Motivate them.  Show pictures of a cold pack and a hot pack.  Raise the question of how can chemistry explain how some things release heat and others absorb it.
  2. The old information the students build on:  Remind students of how energy is treated.
  3. Intro to what we are about to do.  Tell them that the steps in something dissolving can account for for whether a solution gets warmer or colder when a salt dissolves in it.
  4. The new information.  Go through the process, presenting the new material about  dissolving taking place in steps.
  5. Relate to life.  Apply the new information to account for how cold packs and hot packs work.

Lectures can include active learning.  In an “active lecture”, students summarize the material by taking notes, students are challenged to apply the material by answering questions asked by the lecturer, and students are motivated to apply the material to explain real-world phenomena.

One way of bringing active learning into the classroom is to flip the classroom:  the students work on solving problems in the classroom and watch videos of the lecture material outside of class.  In other words, the lecture is still part of the course.  Video lectures have advantages:  the video can be re-watched and paused.  That is a big advantage and is necessary as we move toward delivering courses online.  But I think the lecture is a necessary component of college classes.  If lectures are perceived as a poor way to teach then maybe we need to get better at lecturing.

Update:  April 10, 2019  Here’s a video, What’s the Best Way to Teach Science?, that has some suggestions about how to lecture.