Practical examples
• As the Earth moves round the sun, the sun’ s energy is much more focused and direct at the equator.
• The sun’ s rays near the poles are far more spread-out on the Earth’ s surface.
• Therefore it is hotter near the equator as the intensity of the sun’ s rays are concentrated on a smaller surface area.
Figure 1 – A geographical example of how a teacher might read out information on a slide at the same time as students trying to process the diagram, which is ineffective( Johnstone, 2018).
Figure 1 demonstrates an ineffective teaching method, as spoken and written information is taken into the brain on the same channel, so doing this causes cognitive overload as working memory is limited and is struggling to follow the text. What would be far more effective is to have a large copy of the diagram on the board and to craft a careful explanation that you can verbally give the students, with the aid of the diagram.
Figure 2 portrays an example of an activity which causes cognitive overload, whilst figure 3 demonstrates how this information is easier to process and understand via utilising dual coding in a diagrammatic format.
Figure 3- An example of how the activity in figure 2 can be redesigned to reduce the burden on working memory( Caviglioli, 2019).( Reproduced with kind permission)
Figure 2- An example of an activity which overloads working memory( Caviglioli, 2019).( Reproduced with kind permission)
Considerations for using diagrams in lessons:
Hand drawing diagrams from scratch, step by step, in front of students, is more beneficial than showing a completed diagram on a slide as it reduces cognitive load. This is because the teacher can regulate the flow of information to the student and use explicit instruction to explain each step or component sequentially whilst they draw. They can therefore control the pace of the drawing and explanation, which add students’ focus and understanding as students are directed to look at the relevant part, rather than getting distracted or overwhelmed by the whole diagram. Via this, students can better understand sequences and interlinkages between concepts. Additionally, drawing diagrams from scratch enables teachers to pause and revisit steps of the diagram and explanation if students require, which enables clarity and greater scaffolding of explanations. Therefore, it is important for teachers to have preplanned diagrams they are going to draw in the lesson, which they can then use as an aide memoir to ensure sequencing and chunking of information is remembered and conveyed correctly, in a logical manner, to maximise benefit for students.
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