Many students think that a compact object (such as a ball or a stone) falls at a constant speed which depends on how heavy it is
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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Estimate of acceleration due to gravity using pulsed water drops (11-16)
This experiment is one of the most delightful demonstrations in physics and well worth the effort of assembling the equipment.
View Resource
References
- Halloun, I. A. and Hestenes, D. () Common sense concepts about motion. American Journal of Physics, 53 (11), 1056-1065.
Many students incorrectly believe that moving objects must be experiencing a driving force and that a constant force will cause uniform motion rather than acceleration. This research shows that these ideas need to be challenged repeatedly, using a wide range of examples and demonstrations for students to start to move towards scientific descriptions.
Paper digest - Dilber, R.; Karaman, I. and Duzgun, B. () High school students' understanding of projectile motion concepts. Educational Research and Evaluation, 15 (3), 203-222.
Addressing misconceptions students have about motion can be difficult, especially more complex ideas such as projectile motion. This study demonstrates that interventions can be effective if they are designed to challenge misconceptions explicitly. Simulations can be very beneficial in this process as they allow students to more easily visualise forces and discuss how they affect motion.
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.
