The Grade 9 Namibian Physical Science syllabus

The current Namibian Grade 9 Physical Science syllabus (Namibia. MoEAC, 2015) was developed from the broad national curriculum by the Ministry of Education, Arts and Culture (2015). It has a detailed description of the intended learning and assessment for Physical Science at the Junior Secondary phase (Namibia. MoEAC, 2015). According to this syllabus, Grade 9 Namibian learners are expected to have an understanding of only two types of chemical bonding: covalent bonding and ionic bonding, as discussed in Chapter 2. In this study, I analysed the general and specific objectives of the Physical Science syllabus related

75 to chemical bonding to access knowledge of the visual-verbal demands the syllabus makes on the topic. The results of this analysis will now be discussed.

5.2.1.1The consideration of visual and verbal semiotic modes by the Physical Science syllabus

Gilbert and Treagust (2009) highlight that the combined use of visual and verbal modes in chemistry teaching helps in depicting aspects of a given chemical model, which minimises the challenges of learning it. It was explicated that the visual language of chemistry helps students to understand the sub-microscopic and symbolic levels of representation, which are considered very challenging for students due to their abstractness (Pozzer & Roth, 2003;

Talanquer, 2011). Despite these ideas, and the suggestion by the Namibian curriculum document for teaching to include oral and visual modes (Namibia. MoEAC, 2015), the Physical Science syllabus has not indicated directly how these two semiotic modes should be used in teaching and learning the topic of chemical bonding. However, it suggests to teachers that learners should be able to use action verbs that relate to the verbal mode, such as

‘describe’, ‘define’, and ‘explain’. The specific objectives from this syllabus that suggest the use of action verbs by the learners on chemical bonding state that learners should be able to:

 “describe and distinguish between covalent and ionic bonding as different types of bonding and relate bonding to position (group) of elements in the periodic table;

 describe how non-metal atoms combine with other non-metal atoms by sharing electrons in their outershells with the results that both atoms achieve full outershells;

 describe how the reaction between a metal and a non-metal results in the transfer of electrons from metal atoms to non-metal atoms so that both achieve full outershell and form positive ions (cations) and negative ions (anions) respectively;

 predict the positive and negative charges of ions;

 define ions as atoms with a net electrical charge due to the loss or gain of one or more electrons;

 describe the lattice of an ionic compound as a regular arrangement of alternating positive and negative ions;

 and write the formulae of ionic compounds including polyatomic ions” (Namibia.

MoEAC, 2015, p. 31-32).

The syllabus also suggests to teachers that learners should use visual representations such as

‘drawing’ and ‘illustration’ for both ionic and covalent bonding. For instance, it emphasises

76 that learners should be able to “draw Bohr structures of ionic compounds” (Namibia.

MoEAC, 2015, p. 32). In contrast, the syllabus does not provide guidelines to teachers on how these modes can be used together in a coordinated form for teaching the topic. This revealed the need to consult literature on how these modes may be coordinated, and subsequently, intersemiotic complementarity was identified and built into the overall study.

Employing intersemiotic complementarity in pedagogy draws from the ideas of Gilbert and Treagust (2009). The idea states that coordinating visual and verbal semiotic modes for use as a pedagogic approach to chemical bonding has the potential to remedy the challenges of learning this topic. Hence, the information on the visual and verbal demands, accessed via analysing the Grade 9 Physical Science syllabus, has motivated the urge to plan and implement an intersemiotic complementarity teaching approach to chemical bonding.

5.2.1.2The use of physical models in the Physical Science syllabus

In addition to using diagrams, the Grade 9 Physical Science syllabus suggests that visible models of particles that made up substances may be used. It states that teachers should “build models of atoms, mixtures and compounds by using little spheres of various sizes and colours” (Namibia. MoEAC, 2015, p. 35), when teaching topics related to matter. Pallant and Tinker (2004) suggest that physical models of atoms and molecules are another form of the visual mode considered effective in helping students predict or explain chemical phenomena at different representational levels. They assert that physical models help students relate the difference in states of matter to their motion and behaviour. The physical models help students use atomic and molecular interactions for explaining chemical phenomena they observe at the macroscopic level of representation (Pallant & Tinker, 2004).

I found that the Namibian Physical Science syllabus is silent on how exactly the physical models of atoms and molecules may be used in explaining chemical phenomena taught under the topic of chemical bonding. The details related to using of different coloured and sized spheres to represent particles is helpful but it does not adequately equip teachers with the ability to coordinate visuals and spoken or written words. This leaves sense-making of chemical bonding by learners a challenge. Hence, there was a need to also consider physical models at a more advanced level, as the visual mode, together with the verbal mode, in order to explore the influences of a coordinated visual-verbal intersemiotic complementarity teaching approach on learners’ sense-making of chemical bonding. In this study, using physical models together with the spoken and written language was considered to contribute

77 to designing and implementing an intersemiotic complementarity teaching approach to chemical bonding.