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Table 4; Examples of ‘concept driven’, ‘skills development’ and ‘understanding’ problems Furthermore, the problems are sequenced in such an order so that there is progress development of key concepts and techniques. This is to maximise the potential for cognitive gain and develop with a simple problem to support deve in a non-chemis understanding of acids and bases an Case of the Unlabelled Bot ive ment of process skills. For example, in the first week the students engage try environment and moles and molarity. | op ment of group working skills and problem-solvi with some simple practical tasks to develop th Following on from this, they do a problem based d ways of testing for/ and techniques. The titration technique simple, less accu appreciation fori learning by putti rate ways of determi ts use in quantitative a measuring these. In the third week, the students do is only introduced when they have encountered so ning concentrations and therefore, have more of ng eir on the ttles problem (see below) which further builds on these concepts me an (ce nalysis. Additionally, every effort is made to reinfo ng things in other con knowledge and un derstanding. texts to challenge the students to transfer their ski ls, — Table 4 ; Examples of ‘concept driven’, ‘skills development’ and ‘understanding’ problems Furthermore, the problems are sequenced in such an order so that there is progress development of key concepts and techniques. This is to maximise the potential for cognitive gain and develop with a simple problem to support deve in a non-chemis understanding of acids and bases an Case of the Unlabelled Bot ive ment of process skills. For example, in the first week the students engage try environment and moles and molarity. | op ment of group working skills and problem-solvi with some simple practical tasks to develop th Following on from this, they do a problem based d ways of testing for/ and techniques. The titration technique simple, less accu appreciation fori learning by putti rate ways of determi ts use in quantitative a measuring these. In the third week, the students do is only introduced when they have encountered so ning concentrations and therefore, have more of ng eir on the ttles problem (see below) which further builds on these concepts me an (ce nalysis. Additionally, every effort is made to reinfo ng things in other con knowledge and un derstanding. texts to challenge the students to transfer their ski ls,

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Narelle’s responses to a worksheet on the nature of ions and solutions indicated a fair understanding of nature of ions with some lack of confidence in the reality of the sub- microscopic level. Narelle was confident with the macroscopic and familiar qualities of solutions. In a worksheet about the mole concept, students were asked to show how confident they were about twenty-two statements concerning moles. Narelle recorded “Don’t Know” to six out of twenty-two questions, and indicated a lack of confidence with four other questions conceming A vogadro’s number. Figure 2. Concept map drawn by Narelle in the initial questionnaire MEM] aaa | RARE SER AAU, SAE BE a SR ee Serene ee MALS £4414, 0UL UU In tl he initial questionnaire students were asked to draw a concept map starting with a list of chemical terms. Narelle’s map (Figure 2) indicated that she did not really know what a concept map was, nor did she understand the concepts. Initially, the status of Narelle’s conceptions of the sub-microscopic level was rudimentary; however, she worked hard and improved and her responses to the worksheets during the semester, and the final interview demons trated this growth.

At the beginning of tl t al.’s scheme. Her ini nded to a lack of became orrespo nd she nders al f che surpris models al was practicin ndin nd performed calcu more g of the che ts is often d results conf: ility to unde lations when odelling sk g her m interviews th H modeller. to the equilibriu tial lack of unders comfortable with mical concepts also lependent on rstand chemi completing ills. Towards at she was developi er responses however, because of some incon ng a mental irm that a stu m worksheet improved. Consideri symbols and repre cal concepts. Narel aboratory reports a picture of the sub- he semester, Narelle was a Level 1 modeller according tanding of the various chemical represe f understanding of the concepts. As her modelli chemical symbols and sentations, thi dents’ modelling ability does aff e repeatedly nd preparing microscopic ng abili representatio ring that the co to Grossligh ntations ty improvec ns, hel mmunicatior result is no’ ect their use of used equations for tests, and sc 1S the end of the semester, she conceded during the evel of matter indicated that she was worki sistencies in her responses she was assessed as a Level 2-: ng at Level 3; Figure 3. Narelle’s diagram of the equilibrium situation.

Figure 4. Alistair’s responses to the concept mapping question in the initial questionnaire.

Figure 5. The links that Leanne demonstrated between the three levels of chemical representation of matter. The research has shown how students’ ability to model plays a significant an in learning chemistry. However, while models are ever-present as tools in explaini chemical concepts, the nature of the explanatory tool itself and the skills of modelling are n usually taught directly, but rather indirectly as needed to explain content. Teachers m Duit and Glynn, 1996), though the data from the the case when learning chemistry. Practi evels of representations did improve studen with models and consideration of di modelling ability which in turn was i assume that modelling is an instinctive skill ( three students in this study show that this is fferent nstrume Also, work with these three students h misconceptions that can arise in using mode These secetece shen TBs nature of the sub-microscopic level of [.eanne who began the unit with little or no chemi ntal as matter. S al Pe re ey ee ey es a eee OF i. eran not in students learning the che stry knowledge. mistry concep highlighted a range of difficulties a nd representations to understan This was particularly the case with Narelle a d the abstract d unique role Ce nd i ny Ss Ser fy Sn: cy cee

jtage 1 - Defining the content area of the study an ! Se a Ne Seri GLAS LAR eR OUND T RENE ARRON Based on inspection of the chemistry syllabus, seven types of chemical reactions that were frequently encountered by Y ears 9 and 10 students (15 to 16 years old) were identified. All seven types were introduced to the students in the chemistry scheme of work for Y ear 9 and were included in three major topics, namely, the properties of acids and bases, the metal reactivity series and qualitative inorganic analysis. These seven types of chemical reactions were: combustion of metals, reactions between dilute acids and reactive metals, neutralisation reactions between strong acids and strong alkalis, neutralisation reactions between dilute acids and metal oxides, chemical reactions between dilute acids and metal carbonates, ionic Figure 1. Scheme of development of the Representational Systems and Chemical Reactions Diagnostic Instrument (RSCRDI) based on Treagust (1988, 1995)

Figure 2. Concept map of representational systems for describing chemical reactions

Note: The abbreviations mac, sub and sym denote the macroscopic, submicroscopic and symbolic representations Table 1. Several non-scientific conceptions held by students (N = 65) when using multiple levels of representation to describe and explain chemical reactions.

er Se 4 This interface allows the DVD to contain video of the scientists explaining and showing their research, as well as textual explanations of background theory, equations and a glossary of terms. Multiple formats of graphical information can be included either embedded as part of the videos, or in the HTML-based files, including high-quality three dimensional animations of molecular-level visualizations or simulations of the internal working of instruments. Each module also contains problems for students to work on that are related to the content of the video. In some cases, they are asked to analyze authentic data from the research. A text transcription (script) of each video is also provided. The sections of the DVD are summarized in Table 1. Chemistry Education Research and Practice, 2007, 8 (3), 308-326.

Figure 2. The module menu, showing the main components of the module (on the left) and a list of individual chapters within this module (on the right). Figure 1. Main menu of the DVD interface, showing a link to each module. In this image, the user has rolled over the menu button for the SERS module, which becomes enlarged and outlined.

The PCIP DVD was designed using several of Mayer’s multimedia design principles. Both the multimedia principle, which encourages the use both words and images, and the contiguity principle which suggests they should be present simultaneously (Mayer and Anderson, 1991; 1992), are evident in the design of the main chapter viewing area in which words (in both audible and written form) are present with images (either video or animations). The modality principle states that animations are more effective with narrated rather than written text (Mayer and Moreno, 1998; Moreno and Mayer, 1999). Since the PCIP DVD animations are integrated into the video, the video narration is used in explaining them. The interactivity principle suggests that students should be able to control the pace and order in which material is received in order to maximize learning (Mayer and Chandler, 2001). In the PCIP DVD, students can access any part of the material in any order that they choose. They can watch videos as often as they would like, and can scan through them using the slider bar. Figure 3. The main viewing screen for a module chapter. The video can be viewed here in a split- screen fashion that also simultaneously displays the theory, script, or definitions in separate tabs. The video can also be expanded to full screen view.

Table 2. Demographics of student participants; total number of students is 58.

Table 4. Scoring scheme for pre- and post-tests. Results and discussion Connections between the laboratory course and other areas ea a Throughout all three surveys, several trends became apparent about what students want from this laboratory course. Students’ belief that there should be an explicit connection between laboratory and lecture material was very evident. Even though the laboratory course is designed to be a stand-alone course that students with varied physical chemistry backgrounds take, students seem to want parallels drawn for them between the hermodynamics or quantum mechanical concepts taught in their physical chemistry lecture courses. Most of these students are in their third or fourth year of undergraduate study and are beginning to consider a position in industry or attending graduate or professional school. Having a chance to see how theory applies to problem-solving situations they may be faced with in their career is important to them.

Table 5. Results for question “would you pursue a career in physical chemistry?”

The most common explanation for the large number of “definitely not’ responses was that the students had no interest in physical chemistry. Definitely not. Subject matter does not interest me at all (Student 674).

Figure 4. Graph of pre- and post-test average scores for each question and overall. Regions separated by the thick horizontal lines denote a rough demarcation from lower levels of understanding (bottom) to higher levels of understanding. Statistical analysis aa Sie In order to determine if any of the gains on these questions were statistically significant, the Wilcoxon Matched-Pairs Signed Ranks Test was performed on the data. The Wilcoxon test is designed as a nonparametric alternative to a repeated measures t-test. The data presented here is considered nonparametric because the 0-5 values do not represent an even interval scale. For example, a score of 4 on this scale does not mean the response is twice as correct as a response scored as a 2. Instead of comparing means, scores are converted to ranks and compared at two different times (Pallant, 2001). All Z-scores are greater in

Figure A1. Main menu of the PCIP DVD. Appendix brings the user to the module menu, as show in Each module contains five main components, which are accessible through the module menu: video chapters, animations, problems, theory and script. When the ‘chapters’ link is selected, the screen gives a list of the chapters for that module on the right side of the screen (see Figure A2). Each chapter will open with a ‘tabbed’ view that shows the DVD video in a small window, along with the theory, script, definitions and links available as tabs next to it (Figure A3). The video can also be viewed full screen, and has all of the capabilities of standard DVD video with respect to resolution, flexibility in

Figure A3. Chapter window with tabbed view.

Figure A2. A typical module menu. The DVD can be used either in a computer that has a DVD player, or in a set-top DVD player connected to a television monitor. If used in a computer, the DVD will launch automatically using the NetBlender player. This is a file that is resident on the DVD and does not require any software to be loaded onto the computer. The player is designed to incorporate both HTML content and DVD video into the same interface. The opening screen is a graphical menu of the available modules, as well as links to the help pages and animations index (discussed below). Selecting and item from the main menu oure AJ? sizing, and random access to different time points in the program.

Figure 1. Comparison of Hungarian and American students’ distribution in each category or combination of categories Chemistry Education Research and Practice, 2007, 8 (3), 327-336.

U: Units of matter; C: Constituents of atoms; M: Model of atoms. Table 1. Students’ distribution in each category or combination of categories.

Figure 2. Theoretically possible schemas for connection between three categories (Number of variations in schemes: A =1; B =6; C =3; D =3; E =6).

Table 2. A set of response states of Hungarian 7" graders.

In the output file (Figure 4) we can see the two input files (‘Response states’ and ‘Knowledge states’) and the knowledge states in the assumed knowledge structure, the calculated probabilities of these knowledge states (‘Prob’), the predicted populations (‘Pred Pop’), the original populations (‘Pop’) and the y” value (‘Chi Sq’) for each knowledge state, and finally the total y”? (‘ChiSqT’). This total ? together with the degree of freedom characterise the degree to which the assumed knowledge structure fits to the original response structure. The degree of freedom (d. f.) can be calculated as follows: d. f. = the number of knowledge states in the knowledge structure + the number of estimated parameters (lucky-

Figure 4. A typical output of KST analysis using Potter’s software. Hungarian students’ knowledge structure

Figure 6. The best models for representation of American students’ knowledge structure.

Table 1: Summary of CHEM 217 student surveys of the Home- Study Experiments. was also slightly higher, but essentially the same (5 and 6%). However, the average time since a student has done a laboratory course (4.7 years) was slightly lower than the other groups (5.7 and 6.3 years). There were two major differences observed in the profile of students who did the laboratories entirely at home. First, the proportion of female students (65%) had grown significantly from earlier surveys (41 and 48%). Secondly, there were substantially fewer students with completed university degrees (39%) or college diplomas (22%) than those who had university deg rees (50 and 48%) or college diplomas (45 and 45%) in former survey groups. The increase in the number of female students parallels the trend seen at other Canadian universities and has been generally attributed to a strong economy and employment Opportunities decreasing male participation in post-secondary education. We cannot interpret the observation of the decrease in proportion of previous degrees or diplomas held by chid ante

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