Direct instruction

The aim of this lesson was to improve on the previous experiment and to introduce the concept of extraneous variables.

The class participated in a discussion about what could be improved from the last lesson and then this moved on to a discussion about extraneous variables.

The students then completed the improved experiment before graphing their data, using Google Sheets.

Link to detailed plan


In the last experiment, students found it very hard to see if the Kahoot was asking for numbers to be divided or added. This is because the addition sign + and the division sign ÷ look very similar, especially from the back of the classroom! This provided a great context to discuss what extraneous variables are and how we can attempt to mitigate them (in this case changing ÷ to /).

The lesson could have been improved by giving the students more agency - instead of providing the problem and plan, the students could have created their own from the discussion that we had as a class. Also, students need to be given more of an opportunity to analyse the data. This will happen for our next experiment.

Learning Site Content

Instructions on Google+

The lesson started with a discussion, following this slide.

We talked about previous experiment and then linked the division sign confusion (between ÷ and +) to the new concept of extraneous variables.

Students then completed the improved Number Kahoot - using / instead of ÷. This was the test for the experiment.

The intervention was changing the numbers to words and then retesting using the Word Kahoot.

The information was collated, using Google Sheets, and students were sent a video of how to create a Paired Experiment Arrow Graph.

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