Discriminating chemical structures

A Kelly's triads simulator

This page offers a simple simulation of the technique known as the construct repertory test, or Kelly's triads. This can be used as data collection technique in research, or as a formative assessment activity in teaching.

Try the technique

Below you will see representations of three different*chemical structures. (* As the images have been 'chosen' by a computer, it may offer you duplicates¹ – if so, refresh the screen to get a different selection).

Can you see a way in which two of the structures pictured are similar to each other, but different to the third?
[If so:] Which two belong together in this way (and which is the odd one out?)
Can you describe the way in which the two structures you have grouped together are similar? Can you explain why the other structure is different?
Is there any other way those two structures belong together, but not with the third?
Is there a way you might consider a different pair of the structures to be more similar in some way, compared with the third?
[If so, ask yourself the same questions about that discrimination]
…

If you would like to see different triad, refresh the screen.

Notes:

¹ When a researcher or teacher uses the technique they select three cards from a deck of unique cards, to present to the learner, so the three selected 'elements' (as they are called in the method) will always be different. My simulation is limited!

This example is based on my own use of the technique, using a range of representations I found in chemistry text books.

Here the 'elements' are representations of chemical structures, but the technique has been applied in a wide range of contexts.

Try a version with the names of chemical elements

Try a version of the activity with photographs of a range of animals

Try a version with circuit diagrams

Try a version with photographs as triad elements

Try a version with branches of science

My teaching example with a group with mixed disciplinary backgrounds was a sorting of albums (records/c.d.s)

To read about this research technique, go to this link:

Construct repertory test (The method of triads)

To read a report of how English A level chemistry students construed this particular task, and the range of responses they gave:

Can Kelly's triads be used to elicit aspects of chemistry students' conceptual frameworks?