## Saturday, April 21, 2012

### 2D and 3D Shapes: Week Two

Day 1: Perimeter and Area

Draw a rectangular field on the whiteboard with animals in it. (Draw dotted lines in a grid through the field.) Introduce the concepts of area (how much room the horses have in their corral) and perimeter (how much fence the farmer had to build to make the corral.)

Teach students how to calculate the perimeter by adding up all four sides of the rectangle. Pass out geo boards and geo bands and ask them to make a rectangle that is four spaces long and three spaces wide. What is the perimeter of this rectangle? Repeat for other perimeters, and consider giving the students a perimeter and making them figure out the length and width.

Teach students how to calculate an area by multiplying the length of the rectangle by
the width. Ask students to make their 3 by 4 rectangle again. What is the area of this rectangle? 3 x 4 = 12. Is there another way we can make a rectangle with an area of 12 on our geo boards? What if we had bigger boards? What would the perimeter of that rectangle be?

Give students a copy of the Farm Area worksheet and allow them to start working with
any remaining time. Encourage students to find both the area and the perimeter for each question, and to bring it back completed (areas and perimeters) for a treat. (This will definitely require some parent help, which is good!)

Day 2: Tangrams

Make a set of magnetic tangram shapes. As a review, have the students name each of the shapes and tell which shapes have parallel and perpendicular lines. Tell the students a tangram story, using your shapes on a magnetic board to make the animals and objects in the story.

Print and cut out a tangram for each student on cardstock. Give each student a set of tangram shapes, a piece of paper, and a pencil.  Have students make a picture using their tangram shapes (and trace it onto the page), then write a short story about their picture.  (Encourage students to use all seven tangram shapes to make their picture.)  Tell students that if they take their page home and finish it, they can share their picture and story with the class tomorrow.

Day 3: 3D Shapes

Invite any students who finished their tangram stories and brought them back to share them with the group.

Introduce the following 3D shapes: sphere, cube, cone, cylinder, pyramid, rectangular prism, triangular prism.  Give the students a few Wikki Stix and have them make the best representation of each shape that they can, either alone or in groups.  With each shape, ask students to think of real-life examples of objects that are that 3D shape.  If possible, bring one example of each shape.

If enough time remains, take the students on a quick shape field trip around the school and look for spheres, pyramids, cubes, rectangular prisms, cylinders, cones, etc.