Exploring Students’ Visual Conception of Matterand its Implications to Teaching and Learning Chemistry

Allen A. Espinosa1, Arlyne C. Marasigan1, Janir T. Datukan1

1Faculty of Science, Technology, and Mathematics, College of Teacher Development, Philippine Normal University, 1000 Manila, Philippines

Correspondence should be addressed to Allen A. Espinosa: espinosa.aa@pnu.edu.ph

Abstract

The present study explored how students visualize the states and classifications of matter with the use of scientific models. It also identified misconceptions of students in using scientific models. To elicit data in the study, a Visual Conception Questionnaire (VCQ) was administered to the participants. An interview was then conducted to further inquire if their answer on the questionnaire is agreeing with their own understanding. Participants in the study are thirty four (34) first year general education students in a teacher education institution in Manila. Results of the study show that in general, high percentage of students was able to use scientific models correctly and only a little misconception was identified. Although misconceptions still arise from using scientific models because students fail to account for the use of models to represent different aspects and of the same situation , it is still a better way represent ideas at the molecular level. The role of teachers now is to facilitate students in building models and visualizing ideas.

Keywords: visual conception, scientific models, mental models, states of matter, classification of matter

Background of the Study

In school year 2012-2013, the Philippines started to adapt the K to 12 basic education framework otherwise known as the Enhanced Basic Education Curriculum or EBEC. The shift from the 10-year to 12-year basic education aims to produce globally competitive graduates who are ready to compete with ASEAN countries and beyond. The devastating results of the 10-year basic education framework prompted the government to shift to K to 12. Evidences include the results of the secondary science national achievement test (NAT) in 2007 and 2008 which were reported to be 51.8% and 57.8% respectively. Although there has been a slight increase in the achievement rating, this is still far from the government’s target criterion level of 75% (Lapus, 2009). Furthermore, in the 2003 Trends in International Mathematics and Science Study (TIMSS), out of 45 countries who participated in the study, the Philippines ranked 41st and 42nd in Mathematics and Science, respectively. In the Chemistry part of the TIMSS, it was reported that Filipino students got 30% average correct answers which is way below the international average of 45% correct answers (Martin, Mullis, Gonzales, Gregory & Smith, 2004). The aforementioned studies therefore give rise to a conclusion that the mathematical and scientific ability of Filipino students is very weak when they graduate from the 4-year high school program (Espinosa, Monterola&Punzalan, 2013).

One of the many barriers to higher achievement in Chemistry is its abstract and mathematical nature. Students find it hard to learn chemical concepts since it is being presented at a level that they cannot observe. Teachers usually define terms or describe concepts but they are not presented in a manner that the students can visualize them. Johnstone (1991) reiterated that chemical concepts are better learned at different representation levels: (1) macroscopic level, where students can observe the many applications of chemistry to daily living; (2) submicroscopic or particulate level, where students can account the movement of particles and electrons as well as the structure of atoms and molecules; and (3) symbolic level, where students can quantify matter using mathematical equations and diagrams.

One of the chemistry topics that entail representation learning is the particle nature of matter. Students find it difficult to grasp the particle nature of matter because this topic is usually integrated within the discussion of

1

atomic structure and history of the atom and is not given much emphasis (Harrison &Treagust, 2002). Concepts learned are not reinforced because students are not given the chance to apply the idea of particle nature of matter to different phenomena in the environment. Due to less importance given to the discussion of this topic, students tend to have incomplete understanding or even misconceptions about the particle nature of matter. Novick and Nussbaum (1978 & 1981); Nakhleh (1992); and Lee, Eichinger, Anderson, Berkheimer and Blakeslee (1993) said that students fail to understand that: (1) tiny particles are what comprise matter; (2) spaces are what separate these tiny particles from one another; (3) continuous random movement is evident among particles; and (4) there is attraction among particles in matter.

Science in the EBEC is taught in spiral progression. Biology, Chemistry, Earth and Space Science and Physics are taught in increasing complexity in the junior high school or from grades 7 to 10. The topic on particle nature of matter is part of the grade 8 science curriculum. This particular topic entails learning chemistry at the submicroscopic or particulate level.

Harrison and Treagust (1996, 1998, 2002) repeatedly suggested the use of scientific models to better understand the particle nature of matter. Scientific models (1) are used to think about, explain and predict scientific phenomena, (2) represent objects, systems, events or ideas, (3) describe or predict the behavior of object, systems, or events and (4) may be physical, mathematical or conceptual, such as the particle nature of matter and the nuclear model of an atom (DepEd-NISMED, 2013, p. 118). Although scientific models still give rise to misconceptions because students fail to account for the use of models to represent different aspects and of the same situation, it is still a better way for students to understand the particle nature of matter. The role of teachers now is to facilitate students in building models and visualizing ideas (Harrison &Treagust, 1996, 1998, 2002).

Visual conception through models as mentioned increases concept understanding in chemistry and would therefore promote higher achievement in the subject. However, the implementation and integration of models in teaching chemistry is not yet established. Thus, this exploratory study will assess students’ visual conception of the states and classifications of matter and its implications to teaching the particle nature of matter. Specifically, the study seeks to answer the following research questions: (1) How do students classify matter using visual conception models?;(2) What are the common errors committed by students in classifying matter?; (3) What do the results imply to teaching and learning chemistry?; and (4) What teaching framework can be derived from the result of the study?.

Visual Conception Approaches in Chemistry

The difficulty students face in understanding scientific concepts, especially those in chemistry, stems from a number of reasons. One of these is the presentation of concepts at the abstract rather than the representation level. Apparently, student’s preconceptions and understanding are quite different from those generally accepted in science (Stavy, n.d.) and the use of mental models is limited in comparison with experts and the desired teaching outcomes (Coll& Taylor, 2002).

Indeed, the import of mental-modeling has been highlighted in the extant literature. For example, Chittleborough, Treagust and Mocerino (2002) in their study of the constraints to the development of university chemistry students’ mental models of chemical phenomena, observed that the lack of mental model and the small number of chemical representations, among many others, contribute to this problem. While the students did build up a chemical knowledge framework regardless of these constraints, this knowledge framework was scant and compartmentalized.

In a study of Norway’s University of Stavanger student teacher’s conceptions of matter and substances, Haland (2010) found out that the phenomena of evaporation and dew formation are not well understood. It was pointed out that only 6 out of 31 gave a reasonably correct explanation of the concepts studied as only a few really tried to use the particulate model of matter to explain evaporation and dew formation. This is by itself a result of their conception on matter and substances.

2

In a similar vein, Kurnaz and Emen (2013) contended that school knowledge is not sufficient in structuring the mental models of students in a scientific way. In their study of high school students’ mental models of the contraction of matter, it was shown that while their perceptions were generally scientific, they include insufficient or alternative ideas. Specifically, some students know the truth that the molecules get closer during the contraction of the matter but constraint this situation with the gaseous matters. Thus, they concluded, this situation shows that the ones observed at the macroscopic level have not been degraded into the microscopic level.

Similarly, Jansoon, Coll and Somsook (2009) pointed out that a complete and meaningful understanding of chemistry concepts such as dilution entails understanding of and the ability to integrate mental models at the three levels of representation: macroscopic, submicroscopic and symbolic. In this study of undergraduate students in Thailand’s Mahidol University, it was found out that since their mental models of many aspects of dilution chemistry were generally in accord with scientific conceptualization, they did not show many alternative conceptions.

Wang (2007) also reported that the use of mental models, mental-modeling ability and content knowledge influence general chemistry students’ understanding of molecular polarity and related concepts. Using mixed-method design, it was found out that usually, students have misconceptions associated with electronegativity, chemical bonding, bond polarity and the like. Moreover, these misconceptions and apparently failure to learn about molecular geometry and polarity are a function of the students’ content knowledge and the construction and use of mental models. It was also argued that metacognitive ability played a significant role in the process of mental-modeling and this is barely discussed in researches on the use of mental models or model-based reasoning.

Supporting these claims, Chittleborough and Treagust (2007) provided that an improved modeling ability results to an improvement in non-major chemistry students’ understanding of relevant chemical concepts. The students’ background knowledge in chemistry, as in Wang’ (2007) study, proved to be a powerful determinant of their understanding of the submicroscopic level. It was however pointed out that modeling ability is not necessarily innate and as such, it is a skill to be learnt. Given this, they argued that while models are ever-present in explaining chemical concepts, the skills of modeling are not taught directly. This has implications in teaching chemistry as teachers may assume that modeling is an instinctive skill (Duit& Glynn, 1996 in Chittleborough&Treagust, 2007). Thus, they concluded, this modeling skill should be taught rather than be incidental to the teaching of chemical concepts through incorporation in instruction and through the provision of practice exercises in the application of multiple representations of chemicals and their interactions.

Chittleborough (2014) claimed as well that traditional chemical content and teaching approaches reinforce the lack of connectedness of chemistry with the real world. Because of this, the author calls for the development of chemical epistemology. Examining the interplay between Subject Matter Knowledge (SPK), the philosophy of chemistry and Pedagogical Content Knowledge, alongside the three levels of representations and its roles (Johnstone, 1991), opportunities for the chemistry teacher to be informed about ways students learn in chemistry were identified. Why students find learning chemistry so difficult is explained through the “expanding triangle” and “rising iceberg” theoretical frameworks. The former provides that as students learn more and more at each of the three levels (macroscopic, submicroscopic and symbolic) the triangle expands; however, there is no guarantee that they relate the three levels to each other. On the other hand, the latter explains that initially inexperienced students’ mental models are undeveloped corresponding to the small triangle; as they learn more chemistry, then their mental model expands as they focus on the sub-microscopic level.

Visual Conception Teaching Framework for Chemistry

Because of breakthroughs in technology, the use of visual models for teaching chemical concepts has aided educators to further appreciation of science by students. Several studies have noted the benefits of web-based learning and its potential to empower learning and teaching in terms of its visualization, accessibility and

3

dynamicity (Capri, 2001; Clark, 2004; Linn, Clark &Slotta, 2003; Mistler-Jackson, 2000 in Nahum, et al., 2007). For instance, Wu, Krajcik, &Soloway (2001) argued that eChem, a computer-based visualizing tool that allowed students to build molecular models and view multiple representations simultaneously has deepened their understanding of chemical representations and concepts. It was also noted that computerized models could serve as a vehicle for students to generate mental images.

Caution has been mentioned, however, in using information technology. In a study of multiple representations in web-based learning of chemistry concepts, Vermaat, Terlouw and Dijkstra (2003) reported that the effectiveness of animations must be enhanced. In their work, it appeared that the links between the real, molecular and symbolic world are not strengthened after usage of the instruction material that included animations of chemical processes at the molecular level. In the lessons students are supported and stimulated to make connections between the three chemical worlds and apparently, it appeared that the links between the real, molecular and symbolic worlds were not strengthened after the instruction. The students made more links between the real and symbolic world, but hardly connect these world to the molecular world or vice versa. Eilks, Witteck and Pietzner (2008) also argued that it could be very risky to use animations and visual aids, which have not been thoroughly considered and tested to identify any potential problematic interpretations from the students’ point of view. If these are constructed without sufficient reflection on the learners’ pre-knowledge, animations too often seem to foster misconceptions than promote scientific understanding.

Indeed, the effect of mental models cannot be overemphasized as it is crucial to the students’ understanding of chemical concepts as the preceding literature shows. In the light of the aforementioned problems in understanding chemical concepts, the scholarly literature point out on the need to formulate teaching frameworks to foster effective learning and teaching(Wu, Krajcik, &Soloway, 2001; Vermaat, Terlouw&Dijkstra, 2003; Nahum, et. al, 2007; Yakmaci-Guzel&Adadan, 2013; Chiu & Wu, 2013).

Yakmaci-Guzel and Adadan (2013) contended that the extent of teachers’ subject matter knowledge and the nature of their alternative conceptions might affect how their students understand concepts in chemistry. As a response to this problem, they designed a specific instruction to improve preservice chemistry teachers’ understandings of the structure of matter. While this instruction corrected scientifically inappropriate classifications made, it was found out that some of them reverted back to their initial status months after the introduction of this intervention. Nonetheless, the findings suggest that science teacher educators might consider using multiple representational tasks combined with discussion and collaborative work to offer preservice chemistry teachers opportunities for learning this particular content.

Nahum, Mamlol-Naamanand Hofstein (2008), on the other hand, suggested the use of a new “bottom-up” framework for teaching chemical bonding because of the problems with the traditional approach. Despite the centrality of chemical bonding theory in chemistry, they claim that the traditional curriculum for teaching this is insufficient and to some extent inaccurate. The framework they suggested was based on a collaborative work with chemistry teachers, chemical educators and research chemists. Under this approach the teacher starts with basic principles and ends with specific properties in bonding. Proposing a 5-stage frame where (1) a variety of bonds are introduced to the students from a continuum point of view and (2) a gradual exposure of the main concepts and ideas overcomes the dichotomous classification of bonds without falling into the trap of over-simplification and over-generalization are introduced, the authors argued for its practical benefits. As such, they contend that the framework enhances students’ understanding of bonding and fosters them to think scientifically.

Similarly, Chiu and Wu (2013) suggest formulation of effective learning and teaching materials from an epistemological approach taking into consideration the students’ evolving conceptual structures. The results of their study highlighted that students developed partial or incorrect concepts of microscopic particles before formal education. Apparently, the students’ microscopic views of matter led to different mental models along with many specific misconceptions. As such, they contend, an evidence-based representation of conceptual and evolutionary pathways present in the epistemological approach is needed. This can pinpoint what concepts should be taught before others and support the development of scientific-like models of science concepts. Highlighting the importance of Johnstone’s (1993, 2000) triangle approach and Chui’s (2012) cultural and language perspectives,

4

the researchers advocate the use of systematic methods to uncover teaching and learning sequences to further students’ understanding and appreciation of science in general, and chemistry in particular.

Conceptual Framework of the Study

In view of the literatures presented figure 1 below shows the conceptual framework of the study.

Figure 1. Conceptual Framework of the Study

The conceptual framework of the study shows that through identifying patterns on how students classify matter using models and their common errors in classifying matter through models, a teaching framework for particle nature of matter with the use of models can be formulated.

Research Design

The study utilized the case study qualitative research design to formulate a teaching framework of the particle nature of matter by identifying patterns on how students classify matter using models and their common errors in classifying matter through models.

Sample

The study involved thirty four (34) first year general education college students from a state university in Manila who are currently enrolled in a Physical Science course during the second semester of school year 2013-2014.

Visual Conception Questionnaire

The visual conception questionnaire was originally developed by Punzalan in 2010 and was revised by Espinosa, Marasigan and Datukan in 2013. The revised form was content and face validated by panel of experts coming from the fields of chemistry and chemistry education. Moreover, the revised form was pilot tested to first year general education college students from a state university in Manila who are currently enrolled in a Physical Science course during the second semester of school year 2013-2014. The pilot testing was conducted to determine the readability of the questionnaire and the approximate length of time the students need to answer it. On the average, students finish answering the survey in thirty (30) minutes. Figure 2 shows the final form of the visual conception models used in the questionnaire.

5

Development of a sample learning plan in teaching

particle nature of matter with the use of models

Formulation of a teaching

framework for particle nature of matter anchored

on the use of models

Identification of common errors of

students in classifying matter

using models

Identification of patterns on how

students classifymatter using

models

Figure 2. Visual ConceptionModels

The first page of the questionnaire describes the different states and classifications of matter. Based on the definition and/or description on page 1, students have to identify the boxes that correspond to the information being asked. They have to write the letter of the boxes on the space provided. The information being asked are the following: (1) boxes that are most likely to represent solid, liquid and gas; (2) boxes that are most likely to represent pure substance and mixture; (3) boxes that are most likely to represent element and compound; (4) boxes that are most likely to represent both an element and a molecule; and (5) boxes that are most likely to represent homogeneous and heterogeneous mixtures.

Data Collection Procedure and Analysis

Data were gathered during the midterm grading period of the second semester of school year 2013-2014 in a state university in Manila. The visual conception questionnaire was administered to students. After checking, an interview was conducted to each student who participated in the study. All interviews were digitally recorded and were fully transcribed in accordance with the guidelines presented by Bogdan and Biklen (2007) that interview lengths should range from 30 to 55 minutes, with 38 minutes being the suggested average. The protocols and the accompanying written explanations on the answer sheets served as sources of data for the study.

Results and Discussion

Patterns in Classifying Matter with the use of Visual Conception Models

Looking at table 1, it is noticeable that students find it easy to classify matter according to its state since in most correct options 50% of them or better got them correctly. However, the percentage of students who correctly identified the states of matter decreases from solid to gas to liquid. On the average, students identified 84.56% of the correct models for solid, 57.35% for gas and 42.44% for liquid.

Table 1.Percentage of correct response for states of matter

State of Matter Box Correct Percent

6

Response (%)

Solid

E 19 55.88F 31 91.18M 34 100.0P 31 91.18

Average 84.56

Liquid

B 14 41.18D 18 52.94I 19 55.88K 14 41.18L 16 47.06N 18 52.94O 2 5.882

Average 42.44

Gas

A 31 91.18C 21 61.76G 11 32.35H 28 82.35J 13 38.24O 13 38.24

Average 57.35

Below are selected unedited reposes of students on how they classified the states of matter correctly.

Solid:(a) “Because the molecules/particles are packed tightly with each other.”(b) “Magkakadikit, halos wala nang space at magkakaparehas ng identity.” (The particles are

very close, there’s almost no space in between, and they have similar identities.)(c) “Because these boxes have molecules/particles that are closely together.” (The boxes contain

molecules/particles that are close to each other.)(d) “Because the particles of F, M & P are tightly packed, vibrating about a fixed position.”(e) “Boxes F, M and P are solids because as you can see in the picture, their circles are

compressed and closed to each other leaving only a little space in between.”

In general, students selected models which show that the figures are very close with one another, has little spaces in between and has fixed position. This shows that their visual conception about solid is correct. Conceptually, particles of solids are tightly packed, vibrating about a fixed position. These properties give solids its definite shape and volume.

Liquid:(a) “The molecule has enough space that enables them (it) to slide over.”(b) “The molecules are close but are still able to move a bit. They are not tightly packed.”(c) “Medyo magkakahiwalay at may space sa pagitan ng isa’t-isa.” (The particles are slightly far

apart and there are spaces in between each one.)(d) “Tightly packed rin yung mga particles nila pero apart from each other sila kaya sila

nagfloflow. Pag nag move sila, mag-iislide yung mga particles.” (The particles are also tightly packed but they are slightly far apart, that is why they flow. When they move, the particles slide past one another.)

Checking out the responses of students on how they classify modelsas liquid, generally, they selected models which show that particles are tightly packed, but are far enough apart to slide over one another and has no fixed position. This shows that their visual conception about liquid is also correct because the aforementioned properties of liquids result to having indefinite shape but definite volume.

Gas:

7

(a) “Molecules/particles move free(ly). They are far apart from each other.”(b) “Boxes A, H, C can be classified as Gas because their particles are apart from each other.”(c) “The molecules have a space and they (are) far to (from) each other and move freely.”(d) “The molecules of gases are very far from each other. They can also move freely.”(e) “Very far apart yung mga particles nila at nagmomove sila freely. Pag mas malayo ang

particle, mas may space sila at mas magmomove.” (The particles are very far apart from each other and they move freely. When the particles are very far apart, they move freely.)

Gases, according to the students, in general, have particles which are very far apart and move freely. These properties give gases its indefinite shape and volume. This clearly illustrates that students’ visual conception of gas is also correct.

The ease of classifying the models decreases from solid to gas to liquid. Students find it easy to classify models for solid because of the spaces among particles as well as its position. They also find it easy to classify models for gas since it was just the counterpart of models for solid. However, for the models for liquid, some students find it hard to distinguish between a liquid and a gas due to the relative distances of their particles. Teachers should be very cautious in using models for liquids and gases. They should emphasize and explain fully the relative distances and other properties between the two.

Table 2 shows that students easily distinguished pure substance from mixture. 54.41% of the correct models for pure substance were identified by students and 52.10% for mixture.

Table 2.Percentage of correct response for classification of matter

Classification of Matter Box Correct

ResponsePercent

(%)

Pure Substance

A 21 61.76D 6 17.65E 17 50.00F 20 58.82G 20 58.82H 22 64.71I 22 64.71

M 20 58.82Average 54.41

Mixture

B 20 58.82C 5 14.71J 15 44.12K 26 76.47L 7 20.59N 27 79.41P 24 70.59

Average 52.10

Below are selected unedited reposes of students on how they classify matter as to pure substance and mixture correctly.

Pure Substance:(a) “Made up of one shade of circle. It is uniform in appearance.”(b) “Because these boxes have particles that having the same kind of characteristics.”(c) “Every one of them consist(s) of one size, shape and color particle that shows their

purity.”(d) “Ang pure substance ay one set of chemical and physical properties like nung mga

nasa box(es) na the same na color.” (A pure substance has one set of chemical and physical properties, just like those in the boxes having the same color.)

8

Pure substance is a type of matter that has only one set of chemical and physical properties.The definition suggests that models should have the same or uniform appearance all throughout from the size to the color of the figures. Apparently, students were able to correctly relate the definition of pure substance to its counterpart models.

Mixture:(a) “They are made up of (a) combination of colors.”(b) “Boxes D, P, N, B, (and) K can be classified as (a) Mixture because as you can see in

their boxes there are two or more types of substance(s).”(c) “Because these boxes have a combination of (contains) different particles.”(d) “They have indefinite forms and mixed with other.”(e) “They have different color(s) like in a mixture, they have two or more substances

mixed together.”(f) “They are mixture(s) because there have black circles and white circles, representing

2 substances.”

Mixture, on the other hand, is a type of matter where two or more pure substances are mixed together. Each substance in the mixture retains its own set of chemical and physical properties. This definition suggests that models of mixture should appear differently from each other in terms of the combination of colors and sizes. Seemingly, most students properly relate the abovementioned definition to the models of mixture.

Presented in table 3 arepercentage of response for correct models of pure substance classified as element, compound, molecule or both an element and a molecule. Students easily identified models for an element (65.88%). However for compound (45.10%), molecule (44.12%) and both an element and a molecule (41.18%), students have had a little difficulty identifying the models because the percentage is below 50.

Table 3.Percentage of correct response for pure substance

Classification of Pure

SubstanceBox Correct

ResponsePercent

(%)

Element

A 21 61.76F 26 76.47H 17 50.00I 22 64.71

M 26 76.47Average 65.88

Compound

D 20 58.82E 14 41.18O 12 35.29

Average 45.10

Molecule

D 17 50.00E 16 47.06G 8 23.53O 19 55.88

Average 44.12Element and

Molecule G 14 41.18

Below are selected unedited responses of students on how they classify pure substance as to element, compound and molecule correctly.

Element:(a) “Made up of one kind of particle.”

9

(b) “Magkakalayo pero magkakapareho ng identity.” (The particles are far apart but have similar identities.)

(c) “It is unique in its own way. Like a pure substance it consist(s) of only one size, shape and color of particle.”

(d) “Only one type of atom, they have the same size and color in (the) box.”(e) “Because they only have one kind of circle.”

By definition, elements are substances made up of only one type of atom which cannot be separated by any physical or chemical process. Models having the same size and color all throughout should therefore, represent it. By examining students’ responses, you can see that they easily identified models of elements corresponding to its definition

Compound or Molecule:(a) “Consist of two or more kinds of elements represented by the black and white

circles.”(b) “Combination of small and big circle(s) with combined (a combination of) color(s) as

well.”(c) “It is consist(s) of different variety(ies) of particles. It has different size, shape and

color.”(d) “They have two or more elements chemically bonded together. In a box, they have

the same color but different side/element (element connected to them).”(e) “They are molecules because they have two or more sizes and colors held together.”

Technically, compound and molecule are defined separately. Although a molecule is a compound but not all compound is a molecule. By definition, compound is composed of two or more elements chemically bonded together that has only one set of properties. They cannot be separated by any physical process and can only be separated by a chemical reaction. Molecule, on the other hand, pertains to an electrically neutral group of two or more atoms held together by covalently bond. Since the type of bonding cannot be recognized using the models, compound and molecule are treated as one referring only to the description that they are both composed of two or more atoms or elements. It is therefore expected that the way students classify models for compounds will be the same way as they classify molecules. Apparently, as observed in the responses of students, they classify models for molecules the same way as they did for compounds. From this observation, one can tell that the visual conception of students about compound and molecule is correct.

Element and Molecule:(a) “It is an element because it is made up of one type of particle. Since this one type of

particle is arranged in an orderly manner, it is also a molecule.”(b) “Only G dahil ang G lang ang molecule (attached particle) at pwede ring element

kasi same color and size.” (Only G because G (attached particle) is the only molecule; furthermore, it can also be an element because it has the same color and size.)

(c) “Because they have the same size and color as an element is (should be) and (they are) a molecule (molecules) too since they are bonded together.”

Some elements are not found in the elemental or monoatomic form in nature. They are usually bonded to another atom of the same element and exist in diatomic form. These diatomic molecules such as molecular oxygen (O2), molecular hydrogen (H2) and molecular nitrogen (N2) are considered to be an element and as well as a molecule since it satisfies the description of both - element because it is made of only one type of atom and compound because it is made of two atoms chemically bonded together. Although, this is one of the models where students find it difficult to classify, it is still interesting to know that some of them were able to select the correct model that will satisfy the definition of both element and molecule. In that case, their visual conception of both an element and a molecule is correct.

10

The percentage of correct response of students regarding mixture is shown in table 4. As shown in the table, students find it difficult to distinguish models of homogeneous (8.824%) as compared to heterogeneous mixtures (48.82%). Although students still has a little difficulty identifying models for heterogeneous because the percentage is below 50.

Table 4.Percentage of correct response for mixture

Classification of Mixture Box Correct

ResponsePercent

(%)Homogeneous C 3 8.824

Heterogeneous

B 18 52.94J 11 32.35K 15 44.12N 23 67.65P 16 47.06

Average 48.82

Below are selected unedited responses of students on how they classify mixture as to homogeneous and homogeneous correctly.

Homogeneous Mixture:(a) “Because the boxes has (have) only one phase.”(b) “Components are evenly mixed.”(c) “Because there is only one phase that can be identified.”(d) “It is consist(s) of one size, shape, and color (of the) particle. They can (either) be

close to each other or not.”

Although only a very little percentage of students got the correct model for homogeneous mixture, surprisingly, some students was able to formulate the correct way of classifying homogenous mixture model - components are evenly mixed and that you can only see one phase (represented by a single type of figure). This visual conception of homogeneous mixture is correct.

Heterogeneous Mixture:(a) “They are made up of different particles. Not uniform in appearance.”(b) “P, D, N are can be classified as Heterogeneous mixture(s) because it contains two

or more types of particles.”(c) “Mixture na uneven yung distribution like B, N, P na makikita yung mga

parts/particle.” (It is a mixture with uneven distribution of particles just like B, N, and P where the parts/particles can be observed).

(d) “They have uneven distribution of sizes and colors.”

Heterogeneous mixture is said to have uneven distribution of substances and that you can see the different parts. From the responses on students, one can observe that they were able to relate the definition of heterogeneous mixture with its corresponding model. Therefore, students’ visual conception of heterogeneous mixture is correct.

Looking at the responses of students, in general, one can say that at least half of the students have good modeling skills. They were able to visualize the description or even the definition of each term to visual conception models. During the interview, most of them would agree that it was quite easy for them to visualize models based from descriptions. This might be attributed to a good discussion of the topic during their physical science class. Moreover, based on how students feel towards using models in learning the states and classifications of matter, the class agrees that they better understand the topic when visual conception models were introduced. The result,

11

thus, supports the suggestion of Harrison and Treagust (1996, 1998, 2002) who repeatedly found out in their studies that the use of scientific models help better understand chemical concepts.

Thus, through the continued use and employment of visual conception models in chemistry instruction, students will be able to appreciate the use and importance of it and this might help them improve their conceptual understanding about different topics in chemistry. Therefore, the study might support the claim of Chittleborough and Treagust (2007) that an improved modeling ability will result to an improvement in students’ understanding of relevant chemical concepts. This might also support Wang’s (2007) study, which pointed out that modeling ability is not necessarily innate and as such, it is a skill to be learnt.

Misconceptions with the use of Visual Conception Models

Although in general most students were able to correctly identify models for the states of matter as well as the classifications of matter, there are still some students who incorrectly identify the models. These can be treated as misconceptions or partial understanding about the description and definition of each term. The percentage of incorrect responses, however, is very small as shown in the averages in table 5.

Table 5.Percentage of incorrect responses

12

13

State or Classification Box Incorrect

ResponsePercent

(%)

Solid

B 1 2.941D 3 8.820G 1 2.941J 1 2.941K 2 5.880L 1 2.941N 1 2.941O 1 2.941

Average 4.043

Liquid

A 1 2.941C 4 11.76E 5 14.71F 2 5.882G 7 20.59J 2 5.882

Average 10.29

GasF 1 2.941I 1 2.941

Average 2.941

Pure Substance

B 1 2.941C 6 2.941J 1 2.941K 2 5.882L 8 23.53O 5 14.70P 5 14.70

Average 9.662

Mixture

D 21 61.76E 3 8.824F 1 2.941G 1 2.941I 1 2.941

M 1 2.941O 16 47.06

Average 18.49

Element

B 1 2.941C 4 11.76E 7 20.59G 12 35.29J 1 2.941L 3 8.824N 1 2.941P 1 2.941

Average 7.029

Compound

A 2 5.882B 9 26.47C 7 20.59G 6 17.65H 2 5.882I 1 2.941J 5 14.71K 10 29.41L 5 14.71N 4 11.76P 10 29.41

Average 16.31

Molecule

A 6 17.65B 9 26.47C 3 8.824F 4 11.76H 4 11.76I 3 8.824J 11 32.35K 12 35.29L 7 20.59M 4 11.76N 8 23.53P 10 29.41

Average 19.18A 4 11.76B 6 17.65C 2 5.882D 6 17.65E 10 29.41F 6 17.65H 2 5.882

From the responses of students, in general, misconceptions and partial understanding about the states or classifications of matter are due to the following reasons:

(1) States of Matter:a. Failure to distinguish and compare spaces among figures in the model – which is most

especially evident between models of liquids and solids.(2) Pure Substance vs. Mixture:

a. Failure to recognize that different sizes of figures with the same color are also different. Students thought that they are the same; and

b. Failure to recognize that the different colors of figures with the same size is also different. Students thought that they are the same.

(3) Types of Pure Substancea. Failure to realize that what they should only classify under types of pure substance (e.g.

element, compound, molecule) are the models identified to be a pure substance. Students thought they still have to classify everything;

b. Failure to recognize that different sizes of figures with the same color are also different. Students thought that they are the same; and

c. Failure to recognize that the different colors of figures with the same size is also different. Students thought that they are the same.

(4) Types of Mixturea. Failure to realize that what they should only classify under types of mixture (e.g.

homogeneous and heterogeneous) are models identified to be a mixture. Students thought that they are the same;

b. Failure to recognize that different sizes of figures with the same color are also different. Students thought that they are the same; and

c. Failure to recognize that the different colors of figures with the same size is also different. Students thought that they are the same.

The study actually confirms the study done by Kurnaz and Emen (2013) that even thoughstudents’ perceptions about mental models of matter werescientific, in general, they still have misconceptions and partial understanding about the topic. Although noticeably, only a small percentage of misconceptions and partial understanding were noted. This result is the same with that ofJansoon, Coll and Somsook’s (2009) study about mental models of dilution chemistry where they found out thatstudent’s visual conception is generally in accord with scientific conceptualization and that they did not show many alternative conceptions or misconceptions.

However, the result of the study is in contrary with that of Wang (2007) about using mental models in understanding molecular polarity and related concepts. He found out that students have misconceptions associated with electronegativity, chemical bonding, bond polarity and the like but associated this with the students’ content knowledge and the construction and use of mental models.Chittleborough, Treagust and Mocerino (2002), also supported these findings. In their study about mental models, they found out that students’ concept understanding was scant and compartmentalized.

In different studies done by Harrison and Treagust in 1996, 1998 and 2002, they repeatedly found out that scientific models still give rise to misconceptions due to different factors but they also seen the importance of it in helping students understand different concepts. They just suggest that teachers should facilitate students in building models and visualizing ideas.

Implications to Teaching and Learning Chemistry

14

A skill in modeling is not innate to every studentand is therefore a skill to be learnt (Duit & Glynn, 1996 as cited in Chittleborough&Treagust, 2007). Thus, teachers should not assume that students already have the modeling skill as they enter the class. It is through practice and continued use of models in classroom instruction that they’ll be able to appreciate and grasp the importance of visual models in learning concepts in chemistry. Models help students understand topics in chemistry well but will still lead to misconceptions if not properly guided (Harrison &Treagust, 1996, 1998, 2002).

In this study, scientific models were used to represent ideas. However, scientific models can also be used to think about, explain and predict scientific phenomena, represent objects, systems or events, describe or predict the behavior of object, systems, or events and may be physical, mathematical or conceptual (DepEd-NISMED, 2013).

In particular, in the teaching of particle nature of matter, scientific models can be introduced in the form of a motivation that will also assess students’ prior knowledge about the topic and also their modeling skill. Teachers can also use the models (manipulatives and 3D-simulation) during instruction. He/she can show the models of each state and classification of matter and from that, students have to extract the definition and description of the each given term at the particulate level. Understanding matter at the particulate level develops deep understanding about the topic. The teacher can also do this in reverse, he/she can show the definition and description of each term and students have to visualize the model corresponding to each definition or description. Teachers should be very particular with the shifting of strategy. He/she should always try to reverse his/her teaching strategy to check student’s conceptual understanding. Moreover, the teacher can also provide tangible modeling activities wherein students have to build their own models of matter.

In view of the suggested integration of scientific models in classroom discourse, the following teaching framework is suggested.

Figure 3. Suggested Teaching Framework

The first step for teachers to do is to expose students to conflict situations by showing them scientific models. Then, let them decribe the models based on their own understanding by constructing, demonstrating and observing. After that, allow students to use manipulatives to apply their own understanding by giving them the opportunity to interpret, explain and reflect. From the models constructed and from their description, identify the conceptions and misconceptions of students. Allow students to correct their misconceptions by providing meaningful modeling activities. If done repeatedly in other topics, there is a possiblity that misconceptions will decrease and deep understanding will increase. Deep conceptual understanding will lead to strong holistic information that they can apply into practice to real life situations (Marasigan & Espinosa, 2013). And that is one of the recommendations of the study.

The suggested framework can be followed by chemistry teachers in teaching the particle nature of matter and related topics.

Conclusion and Recommendations

15

Expose students to conflict situations

Students describe their own understanding

Students apply their understanding

Identify student’s conceptions and misconceptions

Students construct new linkages between concepts

DemonstratingObservingConstructing

Interpreting ExplainingReflecting

Storing holistic information(theory and practice)

Scientific models are good to represent ideas and concepts. They help students better understand concepts in particle nature of matter. However, students develop misconceptions using scientific models. The role of teachers now is to guide students in using models. Since modeling skill is not innate to every student, teachers should continue employing scientific models to classroom instruction to develop the skill among students.

It is suggested that this study be conducted also to junior high school students to check their skill in using scientific models. Improvement and revision of the visual conception questionnaire is also suggested. Further, a parallel study should also be conducted to other topics in chemistry that needs visual learning. It is also suggested to check the effectiveness of the formulated teaching framework based from the study.

References:

Chittleborough, G. in I. Devetak and S. A. Glazˇar (eds.) (2014)Learning with Understanding in the Chemistry Classroom, Springer Science Business Media B.V. DOI: 10.1007/978-94-007-4366-3_2

Chittleborough, G. and D. Treagust (2007) Themodelling ability of non-major chemistry students and their understanding of the sub-microscopic level. Chemistry Education Research and Practice, Vol. 8, No. 3 274-292

Chittleborough, G., Treagust, D., and Mocerino, M (2002) Constraints to the development of first year university chemistry students’ mental models of chemical phenomena. Teaching and Learning Forum 2002: Focusing on the Student

Chiu, M. and W. Wu (2013) A novel approach for investigating students’ learning progression for the concept of phase transitions. Emergent Topics on Chemistry Education.Vol. 24, No. 4. 373-380

Coll, R. and N. Taylor (2002) Mental models in chemistry: Senior chemistry students’ mental models of chemical bonding. Chemistry Education: Research and Practice in Europe. Vol. 3, No. 2, 175-184

Department of Education-Instructional Materials Council (2013).Science-Grade 8 Learner’s Material 1st Ed.Eilks, I.,Witteck, T. and V. Pietzner (2009)A Critical Discussion of The Efficacy of Using Visual Learning Aids From The

Internet To Promote Understanding, Illustrated With Examples Explaining The Daniell Voltaic Cell.Eurasia Journal of Mathematics, Science & Technology Education, Vol. 5, No. 2, 145-152

Espinosa, A., Monterola, S, &Punzalan, A. (2013). Career-Oriented Performance Tasks in Chemistry: Effects on Students’ Critical Thinking Skills. Education Research international.Volume 2013, Article ID 834584, 10 pages. http://dx.doi.org/10.1155/2013/834584

Espinosa, A., Monterola, S. &Punzalan, A. (2013).Career-Oriented Performance Tasks in Chemistry: Effects on Students’ Integrated Science Process Skills. Cypriot Journal of Educational Sciences 8(2), 211-226.http://www.world-education-center.org/index.php/cjes/article/view/8.2.6

Espinosa, A., Monterola, S. &Punzalan, A. (2013). Career-oriented performance tasks: Effects on students’ interest in chemistry. Asia-Pacific Forum on Science Learning and Teaching 14(2).http://www.ied.edu.hk/apfslt/v14_issue2/espinosa/

Harrison, A.G. &Treagust, D.F. (2002). The particulate nature of matter: Challenges in Understanding the submicroscopic world. In J.K. Gilbert, O.D. Jong, D.F. Treagust& J.H. van Driel (Eds.) Chemical Education: Toward research-based practice (pp. 189-212). Dordretch, The Neatherlands: Kluwer.

Harrison, A.G. &Treagust, D.F. (1996). Secondary students’ mental models of atoms and molecules: Impplications for teaching chemistry. Science Education, 80(5), 509-534.

Haland, B. (2010) Student teacher conceptions of matter and substances—evaporation and dew formation.NorDiNa, Vol. 6, No. 2, 109-124

Jansoon, N., Coll, R. and E. Somsook (2009) Understanding mental models of dilution in Thai students. International Journal of Environmental & Science Education.Vol. 4, No. 2, 147-168

Johnstone, A.H. (1993). The development of chemistry teaching: A changing response to changing demand. Journal of Chemical Education, 70(9), 701-705.

Kurnaz, M. and A. Emen (2013) Mental models of the high school students related to the contraction of matter. International Journal of Educational Research and Technology.Vol. 4, No. 1, 1-5

Lapus, J. (2009). DepEd:NAT results show steady improvement. http://www.abs-cbnnews.com/nation/youth/09/03/09/depednat-results-show-steady-improvement.

16

Lee, O., Eichinger, D.C., Anderson, C.W., Berkheimer, G.D., &Bladeslee, T.D. (1993). Changing middle school students’ conceptions of matter and molecules. Journal of Research in Science Teaching, 42(5), 581-612.

Martin, M.O., Mullis, I. V.S., Gonzales, E.J., Gregory, K.D., Smith, T.A., &Chrostowski, S.J. (2004). TIMSS 2003: International science report; findings from IEA’s report of the Trends in International Mathematics and Science Study. Chestnut Hill, MA: The International Study Center, Lynch School of Education, Boston College.

Marasigan, A. & Espinosa, A. Modified-useful learning approach: Effects on students’ achievement and conceptual understanding in chemistry. Journal of Education Research and Behavioral Sciences 2(11), 206-228.www.apexjournal.org/pdf/Marasigan%20and%20Espinosa.pdf

Nahum, T., Mamlol-Naaman, R. and A. Hofstein.(2008) A new bottom-up framework for teaching chemical bonding.Journal of Chemical Education.Vol. 85, No. 12, 1680-1685

Nahum, T., Mamlol-Naaman, R. and Hofstein, A. and K. Taber (2007) Teaching and learning the concept of chemical bonding.The Weizmann Institute of Science, Rehovot, Israel

Nakhleh, M. (1992). Why some students don’t learn chemistry. Journal of Chemical Education, 69(3), 191-196.Nakleh, M., Samarapungavan, A., &Saglam, Y. (2005).Middle school students’ beliefs about matter. Journal of

Research in Science Teaching, 42(5), 581-612.Novick, S. & Nussbaum, J. (1978). Junior high school pupils’ understanding of the particulate nature of matter: A

cross-age study. Science Education, 65(2), 187-196.Vermaat, H., Terlouw, C. and S. Dijkstra (2003)Multiple representations in web-based learning of chemistry

concepts. Paper presented at the 84th Annual Meeting of the American Educational Research Association, Special Interest Group Technology, Instruction, Cognition and Learning; Chicago IL, USA

Wang, C. (2007) The role of mental-modeling ability. Content knowledge, and mental models in general chemistry students’ understanding about molecular polarity. Unpublished Dissertation. University of Missouri-Columbia

Wu, H., Krajcik, J. and E. Soloway (2001)Promoting understanding of chemical representations: Students’ use of a visualization tool in the classroom. Journal of Research in Science Teaching.Vol. 38, No. 7, 821-842

Yakmaci-Guzel, B. and E. Adadan (2013) Use of multiple representations in developing preservice chemistry teachers’ understanding of the structure of matter.International Journal of Environmental & Science Education.Vol. 8, No. 1, 109-130

Acknowledgement:

The researchers would like to express their deepest gratitude and appreciation to all those who in one way or another have extended generous support and assistance for the completion of this research study: Dr. Rebecca C. Nueva España, Dr. Amelia E. Punzalan, Dr. Marie Paz E. Morales, Prof. Prince Aian G. Villanueva, Prof. Anna Danica C. Tameta, Prof. Desiree B. Castillo and the Education Policy Research and Development Office (EPRDC) of the Philippine Normal University.

17