I use this lesson to introduce surface area to my 8th grade students. I have found that in the past, teaching surface area of prisms by using the formulas on the formula chart is not only unsuccessful, but incredibly frustrating for me and for the students alike. Big B versus little b? Capital P? Aren’t there 2 heights in this shape? Triangular prisms and rectangular prisms requiring different work, but using the same formula? It was my least favorite concept to teach, and I dreaded it every year. Finally, I decided to do away with the formulas altogether, and really have my students investigate what surface area is. In order to do this.
In the lesson Wrap it Up!, students are given a handout that contains rectangular and Triangulum prisms. They are tasked with determining the minimum amount of wrapping paper necessary to wrap the 3D figure they were given – I told them that I ONLY had enough wrapping paper to cover the surface of each shape without overlapping any paper. Students had to come up with a plan to determine exactly how much wrapping paper they needed, and let me know Students needed little to no guidance, and immediately began drawing out the faces of each shape and calculating the area.
From that point on, anytime they my students have been presented with a problem dealing with the surface area of a prism – lateral or total – they instinctively began to draw the pieces that make up the 3D figure given. No formulas. No confusion. Just a simple understanding that surface area is definitively the sum of the individual areas of a figure.
I hope you like it!