This UK-based study investigates 29 secondary school students' understanding of forces by describing the interactions of characters and their environments in comic strips, including some impossible situations.

Evidence-based suggestions

• Misconceptions persist over long periods and vary significantly between students; reinforcement of the accepted model of forces is required throughout a school programme.
• Students are reluctant to use the correct terms for gravity, so this force should be included in more analyses.

Learners’ ideas

• Students have very unclear ideas about support forces, believing that solid surfaces can offer some kind of ‘complete support’ while liquids and gases can provide only ‘partial support’. They could not explain the cause of these differences.
• Students explained falling in terms of a lack of support, rather than being due to the action of a gravitational force on an object. They also felt that larger things fall faster than smaller ones.
• Students liken motion to continual effort (an unbalanced force).
• Impact forces were seen as being related to the ‘strength’ of particular materials or how fast objects were moving.

Further suggestions

• Students’ "common sense” theory of motion is resilient and will require rigorous challenges through many explanations.

Study Structure

Aims

To expose and empirically test the "common sense theory of motion" which attempts a formalisation of ordinary, everyday knowledge of the physics world. It was proposed by Ogborn (1985) and derived from Hayes' (1979) Naïve Physics Manifesto.

Evidence collection

Evidence was collected via a series of interviews between the researchers and secondary school students. Each student was interviewed on all 15 episodes of the four comics. The interview had two stages:

• Description – the student was asked to describe what was happening in the sequence of pictures.
• Explanation - the student was "Do you think this could really happen, or that it could not really happen?", and to explain why.

Preliminary trials were used to select suitable comic strips. Stories were taken from comic strips and grouped into a series of episodes.

Each pupil's interview was divided into sections covering the 15 episodes. Student explanations were analysed using 4 categories: Support and falling, effort, gravity and impact. The frequencies of the types of explanations were counted.

Details of the sample

The sample consisted of 29 secondary school students, girls and boys, from two English comprehensive schools. In total, 25 complete data sets were obtained. The participant breakdown was:

• 1st & 2nd year – 5 subjects
• 3rd year – 5 subjects
• 4th year – 5 subjects
• 5th year – 5 subjects
• 6th form – 6 subjects

References

Hayes, P. (1979) Expert Systems in the Electronic Age, Edinburgh University Press, Edinburgh, Scotland.

Ogborn, J. (1985) Understanding students’ understandings: An example from dynamics, European Journal of Science Education, 7 (2), 141-150.