Many students think a heavier object will fall faster than a lighter one of the same general shape or size
Misconception
Diagnostic Resources
The following worksheets may help to identify whether students hold this particular misconception.
For more information, see the University of York EPSE website.
In Q4, the wording states that ‘forces caused by the air’ can be ignored. If so, the balls should land exactly together – a result which some pupils may recall as the ‘right answer’. For that reason, part (b) provides a useful check on understanding.
EPSE Gravity Q4Q5 is similar to Q4, but has the advantage of being less wordy. For objects of mass 1kg and 2kg, the correct answer is A, though B might also be defended as plausible.
EPSE Gravity Q5The situation in Q6 is significantly different from that in Q5, as here the weight/area ratio for the table tennis ball is very much smaller than for the golf ball.
EPSE Gravity Q6Resources to Address This
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Falling objects (5-11 and 11-14)
This resource will challenge the common mistaken idea that heavier objects fall faster than lighter objects.
View Resource -
Falling objects: a demonstration (11-16)
It may seem surprising that the motion of all objects falling freely under gravity is the same. A multiflash photograph could be taken of the falling objects to help illustrate this principle to students.
View Resource
References
- Maloney, D. P. () Rule-governed physics: Some novice predictions. International Journal of Science Education, 7 (3), 295-306.
This US-based study asked a sample of college students to complete a series of tasks designed to test their knowledge of force and motion prior to any instruction. All but one of the tasks consisted of presenting the students with two similar physical situations and asking them to predict which would exhibit a certain property more strongly (e.g. "which has higher velocity?").
Paper digest - Bliss, J.; Ogborn, J. and Whitelock, D. () Secondary school pupils' commonsense theories of motion. International Journal of Science Education, 11 (3), 261-272.
Asking students to analyse images from comic strips, rather than the more common force diagrams used in lessons, can be useful in establishing students understanding of forces. The approach also helps to identify misconceptions, based on students ‘common sense’ when they give their descriptions. These ideas are often resilient to change and need to be explicitly challenged in teaching and learning activities.
Paper digest - 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 Monash University, Australia, 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.
- Ogborn, J. () Understanding students' understandings: An example from dynamics. International Journal of Science Education, 7 (2), 141-150.