# Many students do not see forces as arising from an interaction between two objects

Forces and Motion

Misconception

Many students do not see forces as arising from (and during) an interaction between two objects, and always as pairs of equal forces, acting on each of the interacting objects.

## Resources that Address This

• Describing interactions (14-16)

This resource provides a discussion framework for analysing interactions between objects.

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• Selecting and developing activities for finding forces (5-11)

A guide to finding appropriate activities within our resources.

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• Looking through forces spectacles (11-14)

The purpose of this activity is for pupils to make simplified drawings of each of the stations in the circus and to draw in the forces acting on the different objects.

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• Episode 202: Forces in equilibrium (16-19)

In this episode, students will learn about the conditions for static equilibrium (excluding moments of forces).

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## References

• Clement, J. () Using Bridging Analogies and Anchoring Intuitions to Deal with Students' Preconceptions in Physics. Journal of Research in Science Teaching, 30 (10), 1241-1257.

This study aimed to measure the effect of using 'bridging' analogies (analogies with intermediate examples) to address the preconceptions of students (aged 15-18). The sample consisted of ~200 pupils across multiple schools, data was collected using pre- and post-intervention tests, and results were analysed using a t-test.

Paper digest

• Terry, C.; Jones, G. and Hurford, W. () Children's Conceptual Understanding of Forces and Equilibrium. Physics Education, 20 (4), 162-165.

Equilibrium is difficult for secondary school students to fully understand as they cannot clearly picture the forces acting on a stationary object or one moving at constant velocity. This research suggests that teachers develop students’ ability to draw accurate force diagrams for scenarios involving balanced and unbalanced forces before describing changes in motion.

Paper digest

• Minstrell, J. () Explaining the "At Rest" Condition of an Object. The Physics Teacher, 20 (1), 10-14.

This study investigated students' (14-18) explanations for stationary objects in an affluent Seattle suburb. Students drew diagrams of the forces involved in various scenarios, such as books at rest on a table, multiple books held by hand, a book hanging from a spring and a book on a table that is either stationary or depressing. The study recorded student discussions, homework and pre- and post-instruction tests.

• Gunstone, R. F. and White, R. T. () Understanding of Gravity. Science Education, 65 (3), 291-299.

This study presented a sample of first-year physics undergraduates at an Australian university with eight physical situations. The students were asked to predict what would happen if a specific action was taken. The action was then taken, and the subjects were asked to explain any discrepancies between their prediction and the result.

• Brown, D. E. () Students' Concept of Force: The Importance of Understanding Newton's Third Law. Physics Education, 24 (6), 353-357.