## Monday, April 2, 2012

### Hands-on Surface Area of Prisms

Last week we were learning about surface area in my three regular math classes (we did this earlier in my accelerated class).  I had my accelerated students (in groups of three) make a net of a rectangular prism.  They had to measure in inches or centimeters and label each edge of their net, they also labeled each face with the letters A-F).  On a piece of looseleaf they had to give the area of each face and then give the surface area of the whole prism.
 Completed nets from my accelerated math class

I had my regular math students work in their table groups (4 or 5 students per group) to figure out the surface area of the nets that my other students had made.  Now this group did not do any measuring, but they got practice finding the surface area.  I think the hands-on experience of finding the surface area of multiple rectangular prisms helped them to understand the process of needing to find the area of each face and then add them together to get the total surface area.  They were much more enthused and engaged with this activity than they would have been just solving a worksheet with surface area problems.

 Perfect for Easter!  :)

After each group had found the surface area of four different nets (there were 10 different nets total) they then had to find the surface area of a rectangular and triangular prism that I had traced onto centimeter grid paper.  Students had to label each edge with a measurement.  They had to option to put the area of each face on the net, or to label each face with a letter and then write the area off to the side.
 They found the surface area of a rectangular and triangular prism

 Triangular prism

 Rectangular prism

Students had to option to cut the net out and fold it up, but most chose not to cut it out.  If I had math notebooks I may have had them cut it out and then paste it into the notebook.  Students have had lots of exposure to nets as I have the following Geoshapes nets from Nasco.  It is really comical to me how much 7th graders love to play with the nets.  They still love anything they can get their hands on.  I do with that they had a triangular prism that was not equilateral.
I was really pleased with how this lesson went.  In the past students really struggled with surface area.  I even heard one girl who is in my math core plus intervention group say how easy this was!  That's a new one.