# Lesson 3

• Students will evaluate the surface area of the finished birdhouse by evaluating the area of each face, using geoboards, direct counting of squares, or any other strategy.  Each student will evaluate their own birdhouse but students will work in groups and share strategies.
• Within groups, students will report the surface area of their finished house and explain how their answer was obtained.
• Within groups, students will compare their calculated surface area to their "too big too small" estimates.
• Within groups, students will share anything they "noticed" or "discovered."

Set-up

• Students have their own birdhouse, including their final complete birdhouse and their patterns on dot paper.
• Students have pencil and paper, geoboards, (calculators), (metric rulers)
• Student works in groups (of about 4, two of the previous day's pairs).
• If done, students have their "too big too small" estimates from their initial build of their birdhouse.  If that was not done, it is done at this time as a warm-up.

Teacher (whole class)

• Review of the idea of square unit.
• Ask students for one shape, and to remind teacher of strategies to find area for that shape.
• With one birdhouse, model inventorying how many faces it has.
• (Coach students to begin by carefully inventorying their birdhouse faces and to keep track of them.)
• Students will take notes of strategies, calculations, and "discoveries."

Students work in groups.  Each student will evaluate the surface area of their own birdhouse.  Students will share strategies within groups. Students will "convince" each other that they have a reasonable evaluation of the surface area of their entire birdhouse.  Students will take notes of their strategies, calculations, and "discoveries." (Students may need to be prompted to look back at their “too big too little” estimates.)

Synthesis

One student from each group will report any "discoveries"