(for full lesson see links or attachments)
Students will build and label a piece of elastic in increments of 10% and use the elastic to measure and record pictures demonstrating an understanding of the concept of percent in relation to real objects.
In this unit, percent will be understood as the number of boxes colored out of 100. Percent will be understood as an “elastic” number, meaning that the actual amount of a percent changes depending upon what the whole is.
Note: this is a very challenging activity, as it is dealing with the concept that “1” changes. This goes against intuition, as students have come to see 1 as always being 1 object, and now 1 changes depending upon what the whole is.
Lesson guidelines
Elastic percent rulers