**3.2 Procedure**

A pre-test was assigned to learners prior to their exposure to the intervention programme to assess their conceptual knowledge. The pre-test results are illustrated in the form of a table and graph in **Table 3** and **Figure 1**, respectively. The terms on quantitative aspects of chemical change were reviewed with Grade 11 Physical Sciences learners. The learners were then assigned a pre-test to assess their understanding of the quantitative aspects of chemical change from previous grades.

The pre-test results are shown in **Table 3** and **Figure 1**.

As indicated in the diagram, 90% of the learners scored less than 40% and none scored 60% or higher. According to the pre-test results, the majority of Grade 11 Physical Sciences learners were unable to answer questions about the quantitative aspects of chemical change. If this issue is not addressed, it may lead to additional difficulties in this section of Grade 12. As a result, the study proposed a conceptual change approach to solving the problem.


### **Table 3.**

*Pre-test scores in the form of percentages.*

**Figure 1.** *Pre-test scores graph.*

*Implementation of Conceptual Change Approach to Improve Learners' Understanding… DOI: http://dx.doi.org/10.5772/intechopen.114094*

### **4. Intervention**

Instruction on using the conceptual change approach was imparted on learners, which included the application of various tactics such as appropriate comprehension addressing demonstrations and misconceptions. Teaching and learning processes focused on enlightenments to maximise the plausibility and intelligibility of scientific concepts. The researchers prepared conceptual change texts in the quantitative aspects of chemical change.

Instruction was aimed to cover the mole concept, molar mass and stoichiometry, all of which are aspects of quantitative chemical change. When developing the three lessons, the conceptual change stages were holistically considered.

### **5. Conceptual change approach**

Learners were taught through the conceptual change approach, which had the main focus on considering the extent to which scientific conceptions' plausibility and intelligibility could be maximised as alluded to by the four conditions put forward by Posner et al. [9] were used to implement conceptual change, namely dissatisfaction, intelligibility, plausibility and fruitfulness. These four conditions suggest that there are several important conditions that must be fulfilled before the conceptual change is likely to occur.

### **6. Dissatisfaction**

Swafiyah et al. [4] declare that it is a necessary juncture for learners to be efficient at defining and relating terms for a particular concept. By so doing, they would be regarded to have mastered the concept of quantitative aspects of chemical change. The pre-test results revealed that the concept was poorly understood. As a result, the teacher felt it imperative to impose learners in a video lesson before engaging in discussion. The teacher entered the Grade 11 Physical Sciences class. On the chalkboard, the topic for discussion was posed by the teacher, with indications of quantitative aspects versus chemical change. The approach used by the teacher to familiarise learners with the emerging topic was through the review of Grade 10 work. It began with a revision of the mole concept, wherein a mole was defined as equivalent to the volume of a substance.

Following video viewing, the teacher posed a series of questions to the learners. As an example: What is a substance? Learners responded as follows:

What is the scientific name for anything that takes up space?

Learners began to recall work from Grades 8–10.

It is a single atom. [Learner No. 3].

A proton is what it is. [Learner No. 5].

It is a single electron. [Learner No. 6].

Material. [Learner No. 7].

I believe it is matter. [learner].

They were giving various answers, both correct and incorrect and their responses were written on the board. Bloom's taxonomy denotes that the point of departure when teaching is by introducing learners to what they are already familiar with before embarking on imposing abstract or unfamiliar aspects. This type of discussion assisted the teacher in getting closer to the concept from what they knew. Although some of the answers were incorrect, they were throwing related terms together.

The teacher divided the learners into five groups of ten and used the learners' responses to generate activity. Substances, material, matter, atoms, protons and electrons were the terms used. During the presentations, the teacher dispatched learning resources like Prestik and Koki pens to learners grouped according to learner abilities. Thereafter, learners were expected to design personal concept maps, which were later pasted for visibility and accessibility to all. During presentations, learners directed questions to the group that was presented at that particular time.

In the end, learners who had a different understanding of the scientific viewpoint concurred with the outcomes emanating from class engagements. As a result, they retracted how they initially perceived things. Upon further probing, the mole concept was introduced (as this concept had been previously unpacked) and defined as an amount of a substance. Learners understood the word substance but struggled with the word 'amount'? The teacher instructed the learners to look up the word 'amount' in their dictionaries. They came up with various answers that all had the same meaning. They came up with various answers that all had the same meaning as 'many' or 'quantity'.

As engagements were ongoing, learners provided examples of substances for which they were familiar with the quantities. Responses included items like 10 kg of sugar, 12.5 kg of mealie meal and dozens of eggs.

What is the number of eggs in a dozen? [Teacher].

One dozen eggs contain 12 eggs. [B Group].

How many sugar grains are there in 10 kg of sugar? MH! [Teacher] They are too numerous to count. [D Group].

In your opinion, how are granular substances packed?

Learners responded with eagerness, indicating that weighting of objects is used for packaging. [A Group].

The mole was defined by the teacher as a scientific quantity of substances. Periodic tables were circulated to learners to interact with and asked to examine the elements on the table. Explanations were uttered with indications that sometimes it is necessary to know how many particles (atoms or molecules) are in a sample of a substance or how much of a substance is required for a chemical reaction to occur in a single mole of any substance or how much of a substance is required for a chemical reaction to occur. There are 6.023 × 1023 particles in one mole of any substance. It denotes the presence of numerous particles. This is referred to as Avogadro's number. The teacher attempted to persuade the learners about scientific concepts by referring to their discussions, such as how sugar grains could be weighed 1 kg, 5 kg or 10 kg but had many particles inside each pocket.

Learners indicated that they now understood what the term 'mole' meant. Learners indicated that they initially misunderstood the term. After establishing dissatisfaction with learners' the teacher felt implied to further clarify the scientific viewpoint by using worksheets and explanations. Exercises were used to present discussion questions. The teacher went on to explain that if you weighed out samples of several elements, the mass of the sample would be the same as the relative atomic mass of that element.

### **7. Intelligibility**

People need to comprehend the structuring of emergent concepts adequately to investigate the likelihood of inheriting [9]. The teacher introduced the apparatus

*Implementation of Conceptual Change Approach to Improve Learners' Understanding… DOI: http://dx.doi.org/10.5772/intechopen.114094*

into the classroom for learners to accommodate factors that promote new ideas that appeared abstract. The balance scale and filter paper were distributed by the teacher to each group and chemical. Iron fillings were given to Group A, magnesium powder to Group B, sulphur powder to Group C, zinc powder to Group D and copper fillings to Group E. When learners use their senses, they learn more effectively. The teacher gave the learners a worksheet to fill out and a periodic table as support material.

All group members were given equal opportunities to partake in the experiment. During this investigation, the teacher was also hands-on in mentoring and supporting all activities pioneered by each group. When learners experience challenges, they easily interact with the teacher as the classroom environment caters to learner diversity and learner-centred collaborations [E Group].

The teacher explained to the entire class that the number at the top of the periodic table represents the element's atomic number, and the number at the bottom represents the element's atomic mass. Until this point, the teacher had been attempting to share experiences and, at the same time, imparting knowledge by filling in the gaps in what learners already know. Learners felt very proud of the scientific knowledge attained.

### **8. Plausibility**

Plausibility is stage number 3 of conceptual change theory. Posner [9] asserts that emerging knowledge needs to be revealed by learners. At this point, learners are supposed to mentally picture the new concepts they have learned. At this point, the new hypothesis appears plausible.

The learners were exposed to new scientific knowledge, and the teacher was responsible for directing the learning towards cognitive reformation. As the teacher diversified teaching-learning strategies, conceptual change theory was adopted to introduce chemical concepts by engaging in problem-solving tactics.

The teacher provided analogous problem-solving examples. The examples assisted learners in developing problem-solving skills that would allow them to solve higher-order cognitive level questions such as quantitative or conceptual problems. The examples were created using the steps outlined above. The learners were able to conceptualise the problems that need to be solved. The teacher began to delve deeper into calculations involving chemical equations, which had already been introduced in Grade 10. The teacher reminded learners of the chemical change that occurs during the chemical reactions that result in the formation of a new substance. The teacher made an example by sharing that mixing ingredients that have undergone measuring is an important strategy when preparing for baking, explaining that flour has to be in its maximum quantities. As a result, the product was dependent on ingredients that were lesser than others. That is known as a limiting reactant or limiting reagent in a chemical reaction.

Learners responded to the following questions:

Question No. 1.

From the tabled example above, what is the number of tentative sandwiches to be produced?

It is likely possible that one can produce approximately 10 slices of bread and cheese, meaning each slice of cheese is catered for two slices of bread [C Group].

Question 2:

Classify the limiting ingredient in the scenario above.

The group's limiting ingredient is slices of bread. [A Group].

Question 3: Which of the following ingredients is in excess?

There is an excess of cheese because some slices of cheese remain. [D Group].

For students to have a clearer understanding, the teacher felt it imperative to use figures and diagrams to explain the chemical equation, beginning with the reactants, which can be molecules or atoms. To functionally use diagrams together with balanced equations when chemical reactions are being modelled, it is important to note that when equations are balanced, it is then ensured that each element applied on the reactant side produces an equal amount when equated to the product side. The figure demonstrated therefore was intended to indicate that in a case where three carbon molecules were on the reactant side, automatically so the product side correspondingly contains three carbon molecules. As the law of conservation of matter stipulates, reactants can either be solid or liquid and can be described in terms of mass or volume.
