Monday, November 14, 2016

Exploring Polygon Relationships in Scratch

My grade nine class is currently investigating relationships between two variables. I wanted to find some interesting data to look at but also wanted it to be connected to other parts of the course. It occurred to me one day that the geometry portion of the course has students making connections between the number of sides in polygons and the sum of the interior and exterior angles of polygons. This seemed like a good relationship to look at.

I figured this would be a good opportunity to do some coding. I had students visit the Scratch website. A couple of students had used it before, but for most of them this was a new experience. We talked about how you might give somebody clear instructions to walk in a square then we coded those instructions in Scratch and before long everybody had a square. I then instructed students to create a regular triangle, pentagon, hexagon and heptagon. Upon completing each figure they completed the table on the handout.

After collecting the data they proceeded to investigate the relationship between the number of sides and the sum of the interior/exterior angles.

It was fun to watch them. Some started working by trial and error, others were able to make some connections right away. Many who found a solution quickly helped others make the same connections. This was a great way to integrate coding with the relationships and the geometry section of the course.

This activity had me thinking about how I might use a similar activity to have students draw triangles that were not equilateral. It seems like it could be a good application of the sine & cosine laws.

Here's the handout: