What makes public lectures effective?

By Heather King - June 2011


Kapon, S., Ganiel, U. & Eylon, B.S. (2010) Explaining the unexplainable: Translated Scientific Explanations (TSE) in public physics lectures. International Journal of Science Education, 32(2), 245–264.


This paper reports on comparative study of three ‘good’ public science lectures on advanced topics in physics. Based on the analysis it presents an explanatory framework composed of four clusters of elements: analogical approach, story, knowledge organisation, and judicious selection of content. Of particular interest to ISE practitioners engaging in similar public engagement endeavors is the authors’ suggestion that the highest quality presentations use elements from all four clusters.

In the case of physics, hardly any of the achievements of the last hundred years are covered by school curricula, as they require a solid understanding and background in conceptual physics and mathematics. Thus lecturers seeking to speak on such topics have to compensate for the ‘gap’ in required prior knowledge on the part of their audience. To do this, they ‘translate’ ideas using a variety of techniques.

Using the approach of grounded theory, whereby common themes or categories are drawn out of the data; the authors compare three ‘exemplary’ lectures presented by physicists acknowledged to be excellent public lecturers. The data is drawn from transcripts and the Power Point slides of the presentations, interviews with the presenters where they were asked to reflect on way they had developed their presentation, and interviews and open questionnaires with high school students and physics teachers after they watched videos of the lectures. Four clusters of explanatory elements emerged from this analysis:

The analogical approach cluster includes explanatory elements that explain the novel in terms of the known, such as metaphor, different kinds of analogies, etc. The lecturers described these elements as extremely important and powerful explanatory devices but also as the most difficult and challenging elements to design.

The story cluster includes elements that deliver scientific ideas through means that are more common in the literature (fiction) such as narratives, humour, surprise, etc.

The knowledge organisation cluster includes elements that support the audience’s online organization and recall of the knowledge that the lecture presents such as tractability and logic of arguments, explication of outlines, repetitions, etc.

The content cluster includes elements that reflect judicious choice of content, namely what to include, what to omit, and means to achieve this goal.

In their conclusion, the authors found that the above four clusters were addressed implicitly and explicitly by all three lecturers. Moreover, the authors suggest the fact that each lectured had addressed aspects from all these clusters was the reason that the lectures were judged to be ‘good’, namely that they effectively explained the scientific ideas presented. Other lectures that seemed less ‘good in the informed view of the authors who had attended over 30 public lectures in that year were found to have a weak or absent use of elements from at least one of these cluster. Interestingly it would appear that the charisma of the speaker was not enough to ensure an effective lecture!

For ISE practitioners, the analytical framework presented in this study offers a useful framework when planning the preparation of public lectures. Of additional significance for those charged with planning public lectures and the like is the response of several of the high school students who took part in this research. When asked whether they had understood the conceptually challenging concepts presented in the lectures (on quantum mechanics, particle physics and astrophysics) the students said that while they had not understood everything, they had got the ‘big picture’. Further ‘it gave them an idea of what one can actually do in the real world with the rigorous physical laws they were learning’ (page 263). The authors thus suggest that presenting physics in a popular manner may serve not only to inspire the interest students about a topic, but also to help them become literate members in our contemporary society of which science plays a major part.