Learners Ideas and Misconceptions - Essentials of Chemical Education - page 15

In this context, Pfundt created the term “not prebuilt particles” [ 12 ]: they can
appear or disappear. In the other case, there are “prebuilt particles” which exist in
any matter, in crystals, liquids, gases, solutions, etc.
The result of the inquiry was that pupils from grade 7 to 9 mainly chose the
continuity hypothesis and considered “not prebuilt particles.” Only few students
ticked mental models of prebuilt particles and reasoned consequently with the
particle concept for questions of state changes, dissolution and crystallization
processes. For successful teaching the particle concept has to be used in lectures
consequently, it has to be deepened with as many examples as possible.
With model drawings of the structure of matter, Pfundt found out also that
students prefer squares to circles as models for particles. When she asked for the
reason, students answered that models “have to be compatible and it has to be
possible to put them together without gaps” [ 12 ]. Gaps, which do not exist in
students' conceptions, occur when circles are being used: “the horror vacui in
their mental models made them prefer squares to circles as models of particles.”
Novick and Nussbaum [ 13 ] made inquiries on the particle model of gases and
asked: “What is there between the particles”? They offered answers like “no
material, air, vapor, oxygen or pollutant.” They found that the correct answer “no
material” was given by 20-40% only (see Fig. 1.8 ), the majority of high school and
university students in the USA has the conception of air or other matter being
between the gas particles.
Subsequently, other inquiries have been made to find out to what extent the
“horror vacui” exists, concerning the space between the particles in gases [ 14 ]. An
experiment with butane was demonstrated (E1.14) and students were asked for
model drawings and their thoughts about gaps between butane particles in butane
gas (see Fig. 1.9 ). The results of the inquiry showed that students of grade 9-11
could all reproduce the model drawing correctly, but only about 50% of students
ticked “nothing” or “empty.” That means that the other 50% have the conception of
butane, air, or other matter filling the gaps between the butane particles - these
students believe in the “horror vacui”!
Fig. 1.8 Novick and Nussbaum's results of asking about space between particles in a gas [ 13 ]