Picture Perimeters

Why measure accurately?  In this lesson first we practiced measuring the length and width of a 4 x 6 photograph.  We discussed how pictures are framed and how we know what size frame to buy.  During the work period, we measured different pieces of artwork that students in our class produced in the art lab to measure the dimensions (length and width) and then calculated the perimeter of the picture.

We recorded our thinking on our student sheet.  We all used inches so we could discuss our results with our table groups.

We brainstormed times you would use measurement (when you want to know how tall something is, the distance between two points - how far away something is), how long or how wide an object it...

Then we practiced....  We found the more we measured the more accurate we became and the easier it was to measure.

One of the misconceptions was with a piece that was 18 " wide.  When we measured 12" we were accurate.  A boy put his finger down to mark his place and then proceeded to measure 5" on the other side of his finger.  In our closing meeting, he told us he knows his finger is one inch and learned to mark his spot with the tip of the pencil instead so he would get an accurate 18" instead of the 17" he recorded.

The two most important questions students answered, discussed, revised and answered again were written on the bottom of the student sheet:  Why is it so important to measure accurately? and What did you notice about the actual length and width compared to the perimeter?  Made for an interesting closing meeting.

The first time I saw this lesson was when my mentor Suzanne Shall taught it for a demonstration lesson a few years ago.  She developed it and we "borrowed" it.
Post by Mrs. Morris