One girl asked, “Which is hotter, C or F?” This question stumped me. I was trying to understand what misconception could she have to prompt her to ask this question.

 

The next day I took a ruler and measured a stapler. It was 6” or 150 cm long. I asked her which was longer. She said 150 cm. I said no, as it was the same stapler, just different measuring units.

 

Same with C and F. Just different units.

 

I then asked her, “Often thermometers have both C and F scales. Which scale has the units with the big separation, like the larger separation of the inch units vs. the cm units?”

 

To answer this, consider how many degrees there are between freezing and boiling of water. With C, it is 100. With F… She started calculating. I told her 180. Therefore the C has the larger spacing.

 

“Now I understand!” she exclaimed.

 

The lesson we learn from this is that when we use visual objects the abstract ideas become clearer. When she sees a ruler and a stapler the abstract concept of C-F scales becomes clear. We have to make use of concrete models, preferably relating to their own selves, as much as we can.