They were pretty quick to tell me that the parabola opened up if a was positive and opened down if a was negative. I told them the correct vocabulary for this transformation and showed them the sinusoidal transformation activity I used for my grade 12 class. I think this helped them understand why we refer to the transformations the way we do. It was good for them to see that the transformations have the same effect on any type of graph. Then we looked at the effect of the value of a, really the absolute value of a, but since they haven't seen absolute values yet I omitted that part. We looked at everything in terms of patterns and they seemed to grasp how to graph parabolas with vertical stretches and compressions.
We stopped there today. I often ask them to show me thumbs up/to the side/down to gauge how they confident they feel about the material and the many thumbs down coming into class had moved to sideways if not up by the end of the class. They are definitely still shaky on a lot of this, but they are starting to put it together. I asked them if they would like a work period tomorrow to give them a chance to get a more solid grasp on all of this and they enthusiastically supported that idea.
Here is today's homework set.