The Rate of Things

Heather opened up her Grade 8 class to the PLC group for a great intro lesson on rate.  Her class has been looking at rate and ratio a little bit during their science class, but before she proceeded into the unit she decided to do a diagnostic lesson on what they already knew.  She started off with the following question as her minds on:

At first the discussion was going only based on observations about the numbers.  Then Heather moved the conversation into more about unit rates.  The students were able to share ideas freely, and as you can see in the picture made a mistake along the way, but quickly corrected themselves.  This was important to them so they could work on using justification skills and think about what makes sense.

For the action part of the lesson, she took a problem from the curriculum document and modified it to be more "2012" (substituting iTunes downloads for CDs).

When the students were done, three of them came and shared their work with the class.  The group of teachers in the lesson study chose the three groups because each of them used a different strategy to solve the problem, and all the strategies were different and unique in their own way.  Here were the three strategies:

This group made two charts (one for each type of download) and then found combinations that met the requirement of 130 downloads.

This group chose to find the rate in each package for one download.  They they went about finding what would be the best package to get for the 130 downloads.  They also did a bit of cross checking to make sure that they were on the right track.

This group chose to make a graph to visually show their findings.  The first picture shows how they came to their conclusions, but this second picture shows the graph. 

Here is a picture of what the board looked like at the end of the lesson:

After the students left the classroom to go to drama, the teachers de-briefed the lesson talking about what they noticed and where they would go next.  The group noticed that while the class is very good at figuring out the rate, they need some reminders to actually write the whole rate down (e.g, 33 cents per download).  This is a simple thing that can be reinforced when Heather co-creates her success criteria with the class for this unit. 

The teachers also practiced giving some descriptive feedback to the students.  Here is what they said: