RADMASTE molecular stencil

The RADMASTE Molecular Stencil is a rigid, transparent stencil which allows two-dimensional drawing of a number of microscopic entities (Fig. 1), all to the same scale. 

Teachers had to use the RADMASTE Molecular Stencil to answer the following questions ... 

Question 1 - Use a RADMASTE Molecular Stencil to represent the molecular changes corresponding to... 

Whether students had used the RADMASTE Molecular Stencil... 

A total of 84.2%, or 16 of the 19 students, used the RADMASTE Molecular Stencil to create their drawings. In the case of the remaining 3 students, the stencil could possibly have been misplaced at the time, since the particular students completed subsequent questions with the stencil. 

As many as 81.2% of students used the RADMASTE Molecular Stencil in question 1.2, compared to 84.2% in question 1.1. Three students did not use the stencil. Only one student did not use the stencil in both questions 1.1 and 1.2. Two students, who used the stencil in question 1.1, did not do so for question 1.2. The reason for the change in these students approach to molecular drawings is not clear. 

Table lb Results of molecular drawings representing the electrolysis of liquid water, using the RADMASTE Molecular Stencil... 

Question 2 - Use a RADMASTE Molecular Stencil to show the reaction of nitrogen and oxygen to form nitrogen monoxide in the air. Remember that there are approximately 4 molecules of nitrogen for every one molecule of oxygen. Draw a diagram to show the initial mixture (no reaction) and the final mixture (reaction complete). 

Table 2 Using the RADMASTE Molecular Stencil to represent the formation of nitrogen monoxide in the presence of a nitrogen oxygen molecular ratio of 4 1...

Table 3 Using the RADMASTE Molecular Stencil to represent the reaction of 3 molecttles of methane with excess oxygen at extent (i) 0.00, (ii) 0.33, (rii) 0.67, and (iv) 1.00...

When smdents make mistakes in a particular representational system, it could mean that they have not mastered the rules and semantic meanings associated with the representation or that they have not discovered the connection between a familiar and unfamiliar representational system [10]. This was possibly a contributing factor when teachers started to use the RADMASTE Molecular Stencil at the start of the course. 

We are nevertheless optimistic that the experience students had in the present study to use the RADMASTE Molecular Stencil not only provided them with hands-on experience in creating molecular representations, but also developed skills in molecular visualization that they can introduce to their learners once they return to their classrooms. 

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