PASCO SE-8747 Kinesthetics Cart KINESTHESIA-1 - Manual (Page 13)

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012-05787C Kinesthetics Cart
Experiment 5: Eradicating the
Coin Toss Misconception
One student conception we inevitably encounter in an introductory
physics course is known as the “Coin Toss Misconception”. A coin is
tossed vertically up into the air. The question is: “What is the force on
the coin after it has left the hand (a) on its way up, (b) at the turn-
around point, and (c) on its way down.” A standardized test that has
been given to over a thousand students over the past few years shows
that a great majority of all students answer part (a) of this question to
the effect that there is a force in the direction of motion, i.e., in the
upward direction. Certainly, there are many remedies to correct this
student conception. However, this can be done very effectively
through an unforgettable kinesthetic experience.
A student rides on Kinesthesia-1 and is asked to hold on to the constant tension rope of the
“bucket accelerator” introduced in Experiment 4. A force probe is inserted between rope and
hand so that the student can give us many force readings during the entire experiment. Now we
explain to the class that it is impractical to toss a student up into the air to determine the forces
acting on that individual. Therefore, we tilt the coin-toss experiment through a 90
° angle from
vertical to horizontal and now the student sitting on Kinesthesia-1 plays the role of the coin,
while the constant tension rope takes on the role of the gravitational force.
Fig. 5-2. One of the most common student conception, known as the coin toss misconception,
can effectively be corrected using Kinesthesia-1. The experiment is brought from the vertical to
the horizontal. Gravity is replaced by the constant tension apparatus of Experiment 4. The stu-
dent is given an initial push in the “UP” direction (i.e. away from the constant tension apparatus).
The student verifies and reports to the class that the force is constant and in the “DOWN” direc-
tion at all times. In particular, the force is “DOWNWARD” on the way “UP”, “DOWNWARD” in the
turnaround point, and “DOWNWARD” on the way “DOWN”.