Some students are unable to translate between verbal and graphical descriptions of an object's motion
Misconception
Given a distance-time graph or a speed-time graph of an object in motion, students struggle to translate this into a description, in words, of that object's motion. Similarly, given a verbal description of motion, students struggle to translate this into an appropriate graphical representation.
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.
Q17-24 all deal with distance-time graphs. The key idea probed is that the slope of a distance-time graph is an indication of speed.
In Q17-21 the slope of the distance-time graph is always positive (or zero).
EPSE Motion Q17Q22 involves one section with a negative slope.
EPSE Motion Q22Q24 involves selecting the graph which corresponds to a journey described in words.
EPSE Motion Q24Q25-34 probe understanding of speed-time graphs. In Q25-30, the introduction states that the journey is along a straight road, so that the distinction between speed and velocity is not important.
The key idea probed in all of these, and in Q31, is that the slope of the speed-time graph is an indication of acceleration.
EPSE Motion Q25Q32 probes the ability to predict the motion of a ball down slopes of different profiles, and to relate this to a speed-time graph as well as to statements about the motion.
EPSE Motion Q32Q33-34 ask pupils to use a speed-time graph to draw conclusions about distance travelled. These can be answered using knowledge that distance is the area under the graph.
The difference between these two questions is that Q33 does not have numbers on the axes.
EPSE Motion Q33Resources to Address This
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Graphical stories of motion (14-16)
Source - SPT/ Fm02TA05
This resource focuses on students "walking-out" target graphs, and so obtain a real understanding of the story behind the graph.
View Resource -
Timing a trolley on a slope (11-16)
Source - Practical Physics/ Force and Motion/ Time, distance and speed/ ...
This resource outlines a class practical where students measure time, speed and velocity. Graphical presentation of data helps to build concepts.
View Resource -
Ticker-timers for investigating speed (11 - 16)
Source - Practical Physics/ Force and Motion/ Time, distance and speed/ ...
This resource outlines a class activity where making ticker-timer charts can develop an understanding of speed-time graphs.
View Resource
References
The following studies have documented this misconception:
- Bliss, J.; Morrison, I. and Ogborn, J. () A longitudinal study of dynamics concepts. International Journal of Science Education, 10 (1),
99-110.
This longitudinal study examined the concepts that students across a range of year groups held on the topic of motion. The sample consisted of two groups of students: one group of students aged 12-14 and one group of students aged 14-16. 26 students were from middle school, 28 were from upper school, 33 were from secondary school. The study took place in the UK. The concepts were examined using tests and follow-up verbal interviews.
Review sheet
