A Study of Conceptual Formation and Development for Solubility in Elementary and
Secondary School
Liang-Rong Hsu Cheng-Hua Liu
Deparetment of Natural Science Education, National Taichung Teachers College
Abstract
The purpose of this research was to explore students’ conceptual formation and development
for solubility. The subjects include 6th, 8th and 11th grader students. The adapted methods includes
POE(Predict-Observe-Explain) and interview about instance, as well as cross examinations with
previous studies (Hsu and Pon, 2002). During the formation of misconception, students tend to
over-generalize the relationship of “oil, density, and solubility” that formed the misconception of
“all of oil would soluble with water” and “density affective solubility”. This study was based on
Piaget & Garcia(1989)’s model of the development of mechanism in history of science, and
concluded the features of students’ conceptual development for solubility being: Students of lower
grade tend to judge the solvency of a substance based on its apparent properties. When school
experience increases, students have a higher tendency of reasoning the solvency based on density.
Even after students acquired the concepts of acids and chemical formulas in high school, it
appeared that those concepts still coexist in a student’s cognitive structure.
Keywords: Conceptual Development, Conceptual Formation, Solubility
Introduction
This study was a part of the project that was designed to explore students’ alternative
conceptions of chemistry at elementary and secondary schools in Taiwan. The present study intends,
specifically, to investigate students’ misconceptions of solubility.
The science education literature of the past two decades includes numerous studies of young
students’ alternative conceptions or misconceptions about solution (). The classic work of Piaget &
Inhelder (1974) showed the children’s reasoning is governed by perceptual experience when they
were asked to predict what would happen in term of changes in weight and volume when some
sugar was dissolved in water. In the study of Driver & Russell (1982), the results show about
two-third students (9 to 14-years-old English children) predicted the mass of the solution would be
less than the sum of the initial masses of the sugar and water. In an interview study, Ebenezer &
Erickson (1996) identified 11th grade students’ conceptions of solubility. They grouped student’s
conceptions into six categories: physical transformation from solid to liquid, chemical
transformation of solute, density of solute…, etc. In previous study Hsu & Pon (2002) found
students posses notice misconception of solubility in Taiwan of grades 4, 6, 8 and 11. However,
students have misconception or alternative concepts about solubility that had revealed in literature.
But has no researches focus on students’ conceptual formation and development about solubility.
The purpose of this study was to explore cross-age students’ misconceptions of solubility through
their interaction with events in a real situation (predict-observe-explain; POE and interview about
instance; IAI).
The reference model of conceptual development in this study was cited from Piaget & Garcia
(1989). They had propose a model for explain the conceptual development of mechanism in history
of science. We use the model to conduct the students’ conceptual development of solubility.
Method and Procedures
1. POE
The subjects included 98 6th graders, 105 8th graders and 115 11th graders (three classes for
each grade, total N=318). At the onset, the researcher told the students that the task was not an
examination but part of a study with the purpose to know their thoughts about solubility. Glycerin
was used to be the sample for prediction matter. Before having the students predict whether it was
soluble with water or not, the researcher introduced its properties, including name, boiling point,
specific weight, and other important properties. Subsequently, the students were independently
asked to write down their predictions with reason. At the next stage of the task, the researcher
poured the sample (about 10 cc) into a beaker and stirring it about one minute. The students were
asked to independently write down their observations without any discussion. Finally, the students
were asked to compare their observations with their previous predictions and explain any difference
that might arise.
2. Interview about instance (IAI)
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The subjects included ten students of 6th, 8th and 11th graders (N=30). Those subjects has not
participate the POE. There are three cards (table 1) to be as instance in the interview. Each card has
a label show matter’s name, density, formula, boiling point and acidity. The mainly question in
interview were which matter in three cards will soluble with water and why (the reason)?
Table 1. The instance for IAI
Label Card 1 Card 2 Card 3
Formula ××OOH ××S04 ××（H2O）2
Name ××油(oil) ××酸(acid) ××汁(juice)
State of matter liquid liquid liquid
Acidity neutral、PH=7 base、PH=8 acid、PH=4
Density 0.82g/㎝ 3 0.53 g/㎝ 3 0.72g/㎝ 3
Boiling point 250℃ 180℃ 80℃
Color red yellow brown
Results and Discussion
According the results of POE, IAI and previous study (Hsu & Pon, 2002), we conduct the
students’ conceptual formation and development of solubility.
1. The formation of misconception about oils’ solubility--oil, density and solubility
In POE, over one-third students in each grade predicted the glycerin insoluble in water (65.5%,
75.51% and 78.9% for Grades 6, 8 and 11, respectively). After the observation, over twenty percent
of the students in each grade still thought glycerin insoluble with water (15.6%, 25.7% and 34.8%
for Grades 6, 8 and 11, respectively). The reason offered by each grade that has the most percentage
for prediction is “everyday life” and “school experience” (27.8%, 41.9% and 60.2%for Grades 6, 8
and 11, respectively).
In IAI, the Card 1 “xx 油(xx-oil)” similar with Chinese name of glycerin (甘油, sweet-oil).
Most students use density to explain Card 1 would insoluble in water.
0601: ……according the word “oil”.
Researcher: why?
0601: because oil light than water, I had learned that.
Researcher: all of oil insoluble in water?
1109: yup!
Researcher: why?
1109: ……because the density of oil was small than water…then…; I don’t know, anyway,
any oil can’t soluble with water.
The possible processes of the formation of misconception about oils’ solubility show as figure
1. Students aware the phenomena of oil float on water in everyday life and school experience, such
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as gasoline (汽油: gas-oil), varnish (油漆: oil-paint). This experience conduct students make
over-generalization and formed the misconception of “all of oil insoluble with water” and “density
affect solubility”.
everyday life and school experience (infer) all of oil insoluble with water
↙ ↘ ↗
oil float on water → oil insoluble with water → (because) the density of oil smaller than water
↘
(infer) density affect solubility
Figure1. The formation of the misconception about oils’ solubility
2. The conceptual development of solubility
According the Summarize the data of POE, IAI and previous study, we propose students’
conceptual development of solubility (Figure 2) that reference from Piaget & Garcia (1989). The
figure 2 show the feature of students’ conceptual development as follow: (1) the experience of
everyday life and school learning were significant source for students’ conceptual formation. But
the school experience had more obvious affect of higher grades students’ conceptual formation. (2)
The apparent properties of
matter (e.g. state, smell or color)
had attractive to lower graders
students when they judge of the
matter’s solubility. (3) When
school experience increase with
grade, density become dominant
role in students’ mind. (4) When
students acquired the concept of
acid and formula in school, it
would one of criteria for judge of
matter’s solubility and the concept
Figure 2. The conceptual development of the solubility of density that still coexist in
students’ cognitive structure.
The evidence of conduct the feature in figure 2 that such as: (in brief)
(1). The subjects of lower grader students tend to focus on “apparent properties”: The results
of POE indicate the percentage of the students who possess the conception “apparent properties
(e.g. color, smell, liquid) affect solubility” is 24.4%, 7.1% and 0.9% for Grades 6, 8 and 11
respectively. In previous study (Hsu & Pon, 2002), the percentage of the students who thought
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“gasoline soluble with water because they are liquid both” is 26.2%, 15.5%, 2.8% and 2.0% for
Grades 4, 6, 8 and 11 respectively. The example of such as (IAI):
Researcher: Why did you thought it (glycerin) soluble with water?
603: because it’s liquid…… and it has high density.
Researcher: What’s the mean of “state of matter”? (for soluble with water)
604: it has to be a liquid.
Researcher: What’s the mean of “state of matter”? (for soluble with water)
807: is the same.
Researcher: What’s the same ?
807: liquid……because liquid soluble with liquid.
(2). The results of POE and IAI showed the students in each grade students, obvious use density
as the criteria for solubility. Such as, in IAI has 10, 10 and 9, and in POE has 61.1%, 59.2% and
54.1% for Grades 6, 8 and 11 respectively. Additionally, Hsu & Pon (2002) found in each grader had
nearly half students thought “all of oil insoluble in water because they are light than water”.
(3). Higher grade students incline to use acidity or formula as criteria for solubility. In IAI,
judge by acidity (formula) has 1(0), 3(1) and 7(9) for Grade 6, 8 and 11 respectively. Hsu & Pon
(2002) had found the students who thought “acetic acid soluble in water because all of acid soluble
with water” have 61.0%, 62.9%, 80.4% and 82.2% (4, 6, 8 and 11 Grade respectively). The
example of IAI such as:
Researcher: What’s your reason?
1103: Teacher taught about sulfuric acid in chemical lesson, so, I think all of cid soluble
with water.
Researcher: Why?
1103: I had diluted the sulfuric acid.
1106: The formula of this card is -OOH, it should soluble with water.
Researcher: How did you get it?
1106: Textbook and examination in school.
This study has shown that students tend to use their intuitive ideas based on individual reasons
and experiences. However, it seems likely that if teachers and curriculum designers are aware of the
commonly held misconceptions and factors that may contribute to their formation the situation may
be quickly and greatly improved. The teaching should give students the opportunity to test and
change their misunderstanding and formulate more scientific ones.
Reference (brief)
Ebenezer, J. V., & Erikson, G. L. (1996). Chemistry students’ concepts of solubility: A
phenomenography. Science Education, 80(2), 181-201.
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Hsu, R. Z., & Pon, U. E. (2002). A study of primary and secondary students’ misconception of
the classification of matter: An example of solubility. Paper presented at third annual meeting of the
Chemical Education of Republic of China. Changhua: National Changhua university.
Piaget, J., & Garcia, R. (1989). Psychogenesis and the history of science. New York: Columbia
University Press.
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