## Some younger students do not associate the phenomenon of weight with the force of gravity

Forces and Motion

Misconception

• Gravity related to mass and 'weight' (5-11 & 11-14)

Source - SPT/ Fo03PN04 & Mf03PN08

This resource gives some classroom discussion points on the relationship between mass, weight and gravitational force.

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• Differentiating between mass and the force of gravity (11-14)

Source - SPT/ Fo03TL06

The distinction between mass and weight can often seem pernickety, unnecessary and not particularly helpful. However, in physics, the mass of an object and the force acting on an object are very different measures.

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• The Earth's gravitational pull (11-16)

Source - Practical physics/ Force and motion/ Introduction to forces

Gravitational force can act 'at a distance'; it shows little variation over short distances, but does vary over larger distances.

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## References

The following studies have documented this misconception:

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

10-14.

This study examined the explanations given by two classes of high school students in an economically affluent suburb of Seattle for objects at rest. Students were asked to diagram and defend the forces involves in a series of examples including (i) book at rest on a table, (ii) book held by hand, (iii) multiple books held by hand, (iv) book hanging from a spring, (v) book at rest on a table which is shown to depress, (vi) book at rest on a table again. Recordings of student discussions were made, and homework papers, as well as pre- and post-instruction test results were examined.
Review sheet

• Graham, T. and Berry, J. () Students' intuitive understanding of gravity. International Journal of Mathematical Education in Science and Technology, 24 (3),

473-478.

This study administered a questionnaire to a sample of 202 students in the UK between the ages of 16 and 18 from a range of city and rural comprehensive schools, private schools and sixth form colleges.
Review sheet

• Trumper, R. and Gorsky, P. () A cross-college age study about physics students' conceptions of force in pre-service training for high school teachers. Physics Education, 31 (4),

227-236.

• Smith, C. Carey, S. and Wiser, M. () On differentiation: A case study of the development of the concepts of size, weight and density. Cognition, 21 (3),

177-237.

In this study, a sample of 78 children in the United States, aged between 3 and 9 years old participated in a six tasks designed to probe their understanding of weight, size and density. A combination of verbal and non-verbal tasks were used and interviews were conducted.
Review sheet