# Many students think that an object that is moving along a curved path will continue to follow a curved path when its motion becomes unconstrained

Forces and Motion

Misconception

### Diagnostic Resources

• Whirling a rubber bung and letting go (11 - 16)

This resource is used in the classroom to show the tangential motion of an object when it is released from circular motion.

Also see Introduction to Circular Motion, another activity in the same group.

View Resource
• Going around in circles (11-14)

Demonstrate that when the string is cut the centripetal force is removed and the bung leaves its circular orbit, continuing along a tangential path.

View Resource

## References

• Bliss, J., Morrison, I. and Ogborn, J. () A longitudinal study of dynamics concepts. International Journal of Science Education, 10 (1), 99-110.

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

• McCloskey, M., Caramazza, A. and Green, B. () Curvilinear Motion in the Absence of External Forces: Naïve Beliefs About the Motion of Objects. Science, 210 (4474), 1139-1141.

47 US-based university students (15 without formal physics education, 22 with high school physics, and 10 with university-level physics) were asked to draw the path a moving object would follow in several different situations. Over half of the students evidenced striking misconceptions: many believed that even in the absence of external forces, objects would move in curved paths.