I.  Preparing  (To plan for instruction)

Alabama Course of Study:  Mathematics, pages 30 – 31, numbers 29, 30, and 34.

Cardboard cutouts of polygons, pompons, glue.

Children’s literature:  The Greedy Triangle by Marilyn Burns.

Overhead projector, transparencies of polygons, straw pieces.

Polygon outlines on cardstock (laminated), straw pieces.

Posterboard (laminated), dry-erase pen.

(Analysis)  Identify whether a measurement situation calls for area or perimeter.

(Application)  Calculate perimeter using iteration with nonstandard units of measurement.

(Synthesis)  List real world uses for perimeter.

II.  Orienting    To establish purpose, build background sustain motivation, and provide directions  

The teacher will express to the students that they will be learning new use for measuring.  The teacher will say, “This new way can make measuring objects very easy.”

The teacher will say, “The purpose of this lesson is to give you a new way to use what you already know about measurement.  After today’s lesson you will be able not only to measure the length of something, but also to find the measurement around an object.

The teacher will say, “You have already learned how to measure length.  Today we will learn how to measure perimeter, the distance around an object.”

III.  Presenting    To use sequential direct instruction  

The teacher will define “perimeter”.  The teacher will say, “Perimeter is simply the distance around a figure.”  The teacher will write the word “perimeter” on the board.  

The teacher will define “area”.  The teacher will say, “Area is the total number of square units that a surface has.”  

The teacher will have the students feel the difference between perimeter and area by having the students close their eyes and use their touch to examine two cardboard polygons, one of which has pompons glued around the edge (perimeter) and the other which has pompons glued all over its surface (area).  

The teacher will say, “We find the perimeter of a polygon by measuring each of its sides, then adding the measurements up.  

The teacher read the book The Greedy Triangle.  To review the polygon shapes, the teacher will ask the class the name of each polygon as it appears.  The teacher will ask the class how many side they would have to measure to find each polygon’s perimeter.  

The teacher will say, “We can measure perimeter using many different things.  We can use pompons, toy cars, inches, centimeters, even our hands.”  

The teacher will have the students measure the perimeter of their desks, using their hands.  

IV.  Practicing and summarizing  To reinforce and extend ideas  

(Application)  The teacher will call on volunteers to point out the perimeter of several items in the classroom (board, window, floor, etc.)  

(Analysis)  The teacher will ask students to identify whether different situations call for a perimeter or an area measurement using a show of hands.  

     Situation 1:  measuring to put woodchips on a playground

     Situation 2:  measuring to put a Pokemon wall border on your bedroom

     Situation 3: measuring to put carpet on the floor  

     Situation 4: measuring to frame a picture you drew with stickers

(Synthesis)  The teacher will call on volunteers to offer ideas of when to use perimeter.  The teacher will allow students to record answers on a class idea chart.  

The teacher will give everyone a polygon practice sheet and a straw piece.  The teacher will use the overhead and transparencies so everyone can see.  

The teacher will measure the perimeter of a square using a piece of straw.  

With the teacher modeling and guiding each measurement, the students will participate using their straws to measure a right triangle and a rectangle.  

The students will get in groups of two.  The teacher will give each group a new sheet, consisting of four polygons to measure:  a parallelogram, an octagon, an isosceles triangle, and an L-shape.  

Working together, one student will measure two of the polygons, while the other records the results.  The students will then trade tasks.

The teacher will say, “Today we learned what perimeter is, how to measure it, and when we need to use perimeter.  I want everyone at home tonight to measure the perimeter of one thing and be prepared to share it with the class tomorrow.  

V.  Assessment:  (To check for attainment of objectives)

The teacher will use a checklist to assess the class discussion, guided and independent practice.  The checklist will have the objectives listed as column headings.  Checks and minuses will be used to determine attainment.

For enrichment, those students will be asked to construct polygons using the geoboards, then calculate each polygon's perimeter.

For remediation, those students will be given a sheet with a simple polygon on both sides and a number of straw pieces.  The student will cover the lines of the polygon with the straw pieces, then simply count the number of straw pieces to determine perimeter.

http://www.athens.edu/pt3/vinson/area.ppt