Public science lectures: What for? How to?

by Stephanie Chasteen on November 23, 2009

I recently read two interesting articles on translating science for the public — in particular, why we give lectures for the public at all, and some effective ways to do it.

For those of you who are interested, here are the original source articles:

  1. Explaining the Unexplainable: Translated Scientific Explanations (TSE) in public physics lectures, Kapon, Ganiel and Eylon, International Journal of Science Education, 785022307, p 1-20 (2009)
  2. Scientific argumentation in public physics lectures: bringing contemporary physics into high- school teaching, Kapon, Ganiel and Eylon, Physics Education, 33 (2009)

Carl Sagan -- the quintissential expert lecturer

Carl Sagan -- the quintissential expert lecturer

Contemporary physics topics are inaccessible to most high school students.  They need a lot of prior knowledge to follow them, which they don’t have yet.  So, we are often presenting complicated ideas to an audience who knows nothing about this.  But there’s another forum where we do this quite regularly — public science lectures.  What do effective public lectures have to tell us about explaining complicated concepts to high schoolers?

How do we translate complicated ideas to a lay audience, without being inaccurate? We must walk the fine line between understandability and inaccuracy.  My old mentor, Paul Doherty at the Exploratorium, taught me to think carefully about this line.  You can’t be as accurate and detailed as you might want to be when explaining things to the public.  As scientists, we are used to giving every caveat and detail in order to have no way to be misunderstood.  As communicators, instead, we need to leave out those details, and do our best at being understood in the broadest sense.

In public lectures, we are just promoting a sense of understanding and engagement, a “wow” factor, rather than deep understanding.  But this is a laudable goal.  Science is a cultural endeavor, just like music, and good lectures give people a window on this culture.  One can liken it to a music performance.  Someone who has not studied music will experience a concert on a very different level from someone with a PhD.  But they can still appreciate the beauty and aesthetic, and enjoy dipping their toes into this different world.  Similarly, physics lectures can give people a sense of what people do with physics in the real world, which is as important to science literacy as an understanding of scientific content.

There’s not much research on how “expert” lecturers manage to convey complex topics in this way.  So, these authors wanted to define just what it was that makes a good public lecture.  They gave three public lectures, and surveyed high school students and teachers afterwards to assess the impact.  This is a preliminary study, with just three lectures.

Not unsurprisingly, there was a big gap between the content in the lecture and what audience remembered and understood.  However, if the audience felt that they completely missed understanding the content, then it’s very demotivating.  So the lecturers had to find some way to bridge the gap in audience understanding, to give them some sort of explanatory framework. They found many charismatic lecturers, but many of them lacked the strength of explanatory power that is created by inclusion of the following elements.

Four aspects of successful lectures (as defined by these authors):

1. Use analogies, metaphors and visuals.

Explain something new in terms of something known.   For example, “A quantum particule lives through many parallel histories, as long as it does not leave a mark.”  They found that many audience members used these same analogies when summarizing the lecture.  These devices are used more in public lectures than in classroom lectures to bridge the gap in understanding.

2.  Tell a story

The importance of the use of humor, narrative, characters and protagonists, with cognitive conflict and some sort of surprise.  Speak in colloquial, casual language.
For example, A alien comes to earth and looks at people and sees that there are older and younger people.  Realizes that younger person will get older like the older person.  When we look at sky we see stars.  Similarly, we realize that there are older and younger stars.
These narratives provide coherence and a sense of understanding. That’s all we need in public lectures, a sense of understanding — this is not a class!  After a movie, for example, we don’t ask ourselves what the meaning of the movie was during every minute — we leave the movie with an overall impression.

3.  Knowledge organization

This is the structure of the lecture — using repetition, stating the outline, giving clear logic and visual aids.
For example, during one lecture an empty table of properties of elementary particles was filled in.   Many lecturers repeated ideas, bringing the ideas deeper and deeper each time (“spiraling”) to drive the point home.

4. Content

This is what we usually think about when we’re putting together a lecture.  What do we omit, what do we include?  At what level do we go into?  What do we simplify?  It’s important to keep in mind people’s cognitive load — how many new ideas they can process in a period of time.  This requires understanding of the audience’s prior knowledge.  Lecturers most aware of this aspect of what they do.
The general rule:  Omit and simplify.  If you’re going to lose the audience over it, toss the complicated explanation.

How might teachers use public physics lectures in their courses?

When a subject (like 20th century physics) isn’t in their textbooks, the use of public lectures (on the web) can help them enhance their course content.  The authors suggest that teachers use the previous four categories to ascertain whether a physics lecture is “good” or not, to decide whether to use in the class.

Unlike a public lecture, the goal of a physics class is for students to understand the scientific arguments, rather than just promoting a vague sense of understanding.  So the lecture has to be accompanied by learner-centered activities to cement the ideas.

The authors used public science lectures as part of a course in the following way in an online course.

  1. Watch lecture on own and fill out worksheet summarizing points
  2. Online discussion with others about worksheet, real time viewing of desktop and comments on worksheet
  3. Online discussion in class
  4. Reading of popular papers and posting questions in forum, reflection
  5. Created group summary of lecture, using a guided matrix.  They decomposed the lecture into arguments and analyzed each argument, explaining which aspects of the scientific method were reflected in the lecture.

However, using videos or doing reflective activities like this in class take time.  Many teachers in their study complained about this, and many didn’t end up using the activities for that reason.  I’d be interested to hear working teachers’ take on this — would you use videos in your class and do these kinds of activities with them?  What kinds of activities or videos would you use (or do you use) in your class?


Zeke Kossover November 23, 2009 at 3:16 am

After a long series of posts on a physics mailing list where one side complained that the other side’s explanation was inaccurate and the other side argued that the first side’s argument was incomprehensible, I formulated my Law of Explanations.

(ease of understanding)(accuracy) = or < Feynman’s Constant

where Feynman’s constant varies for each individual and measures how good the person is at explaining.

sciencegeekgirl November 23, 2009 at 5:19 am

I like it — a formula for evaluation of explanations. Thanks for the comment, Zeke. And thanks for the information on laser levels ages ago, which I posted last week. If you still have those images (the url’s from the original email didn’t work) I’d love to include them in that post!

wastewater treatment chemicals December 14, 2009 at 8:20 am

I like public lectures, esp. those can tell good story for the theme.

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