In this clip the teacher is having a discussion with a small group about what proportionality is and allows them to use the context of constant speed to explain.
Proportionality and Constant Speed, Clip 3, 2:07
The teacher (on the left) is having a discussion with a small group about proportionality.
Notice the teacher requires justification saying, “what do you mean by same amount?”, to which the student corrects herself and says same percentage.
The teacher then asks if it works in their situation and since the student’s definition was in percentage, the teacher requests the change in time in percentage. The situation is linear but not proportional and the teacher leads them to check via percent changes. It may be necessary to give such guidance, especially early on in the module.
