This activity will help students understand that most shapes are made up of other shapes.
This activity provides students with the opportunity to construct geometric shapes in a small group, exploratory setting. Students use pattern blocks to create two different 3-sided, 4-sided, 5-sided, 6-sided, 7- sided, 8-sided, 9-sided, and 10-sided polygons. Each polygon construction should be made up of at least two pattern blocks pieces (although the pattern blocks do not need to be different). In addition, sides of the pattern blocks should match up (as will be demonstrated in the session). Students record their constructions, utilizing a choice of methods that will be introduced (cutouts, stamping, tracing).
This particular activity allows students to realize that shapes are made up of other shapes. Once the constructions are complete, the activity serves as a knowledge base that the students will refer to in later activities to learn about the following concepts: convex polygon, concave polygon, symmetry, interior angles of a polygon, sum of the interior angles of a polygon, number of vertices (sides, angles) of specific polygons.
2. Become mathematical problem solvers.
6. Represent mathematical situations.
Invitation to Learn:
Prepare a set of words with the same prefix as several of the polygons
the students will construct, (e.g., trio, and triplets for triangle, octave,
octopus, and octet for octagon, etc.) Prepare sets for at least: triangle,
quadrilateral, pentagon, hexagon, octagon, and decagon. Divide the class
into 6 groups. Have them use a dictionary to look up each word and
write down a brief definition. Then have them observe what all of the
words in their list have in common. Have groups share findings to
reinforce the names of the polygons.
Instructional Procedures:
Once the polygons have been constructed, they serve as a rich knowledge base from which the students can explore other geometry concepts. For example, after the teacher introduces the concepts of convex polygons and concave polygons, students can go back and label each of the polygons they constructed as either convex or concave. Similarly, the students can use a mirror to test for line symmetry. If they find symmetry, they can draw dashed lines to indicate where the line of symmetry is.
Ask students about the strategies that they discovered when they constructed the polygons. For example, some students might come up with a strategy for certain polygons to get one more side by putting a triangle where there was a straight side before.
Homework & Family Connections:
Students can repeat or continue the activity at home with help from
family members. They might be challenged to construct shapes using the
fewest possible number of pattern block pieces.
Observation and questioning are good informal strategies for this activity. The teacher can observe and ask individual questions while the students are working in their groups, as well as when the students share their findings at the end of the lesson. The completed record of the polygon constructions is a good formal assessment.
A possible journaling prompt is "In your journals, write about the experience you had building the shapes. Include thoughts about which ones were more difficult for you (e.g., ones with an odd number of sides or an even number of sides) and any strategies you used."