Use Johnstone’s triangle to understand calculations relating to the number of moles of gold in a gold ring

With this resource, learners connect moles and mass at the macroscopic, sub-microscopic and symbolic level. They use the macroscopic measurement of the mass of a gold ring to calculate the number of moles of gold, before then calculating the number of gold atoms forming the ring.

  • Student and teacher moles of gold sheets on orange-red background index image

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    Use this student worksheet to introduce calculating the moles of gold and link to learners' understanding at three different conceptual levels.

 Learning objectives 

  1. Recognise element symbols based on Latin names. 
  2. Calculate the number of moles of gold from the mass and relative atomic mass. 
  3. Calculate the number of atoms of gold in a ring. 

How to use Johnstone’s triangle

Use Johnstone’s triangle to develop learners’ thinking about scientific concepts at three different conceptual levels:

  • Macroscopic: what we can see. Think about the properties that we can observe, measure and record.
  • Sub-microscopic: smaller than we can see. Think about the particle or atomic level.
  • Symbolic representations: Think about how we represent chemical ideas including symbols and diagrams. 

For learners to gain a deeper awareness of a topic, they need to understand it at all three levels.

When introducing a topic, do not try to introduce all of the levels of thinking at once. This will overload working memory. Instead complete the triangle over a series of lessons, beginning with the macroscopic level and introducing other levels, in turn, once secure.

All of the levels are interrelated, for example, learners need visual representation of the sub-microscopic in order to develop mental models of the particle or atomic level.

Further reading 

Read more about how to use Johnstone’s triangle in your teaching with these articles:

Norman Reid’s book The Johnstone triangle: the key to understanding chemistry provides a more in-depth overview, the first chapter is available to read online.

Scaffolding 

Share the structure of the triangle with learners prior to use. Tell them why you are using it and how it will help them to develop their understanding. Use an ‘I try, we try, you try’ approach when introducing Johnstone’s triangle for the first time. 

Next steps

To further develop learners’ thinking in all areas of Johnstone’s triangle, try our Developing understanding of moles and mass worksheet. This includes icons in the margin referring to the conceptual level of thinking needed to answer the questions.