## It's a Ball, It's a Sphere … No, It's a Dodecahedron

### Cindy BeckhamSanta Rosa District Schools

#### Description

Students construct a dodecahedron that displays facts about two and three- dimensional figures.

#### Objectives

The student knows the properties of two- and three-dimensional figures.

#### Materials

-Patterns printed on cardstock (see attached file)
-Tape (cellophane tape works best)
-Colored pencils, crayons, or markers
-Math textbook or dictionary
-A classroom set of scissors

#### Preparations

1. Have patterns copied onto cardstock.
2. Collect scissors, colored pencils, and markers.
3. Construct a dodecahedron as an example for students.
4. Provide dictionaries for student use.

#### Procedures

1. Begin the class by tossing up and catching the teacher-made dodecahedron.

2. As the students watch, have them describe the dodecahedron.

3. Write the word -dodecahedron- on the board. Explain that the prefix, “dodeca,” means twelve and that “hedron” comes from the word polyhedron (a solid figure whose faces are polygons).

4. Explain to the students that they will be constructing dodecahedrons of their own using the patterns that are provided.

5. Before giving out the patterns, hold up a pattern and explain to the students that they will need to write a fact, in a complete sentence, about two and/or three-dimensional figures on eleven of the faces before cutting out the patterns. Have them write their names on the twelfth face. They may use pencils, colored pencils, or markers to write their facts. Inform the students that the success of the construction is determined by how carefully they cut along the solid lines and by how neatly they fold along the dotted lines.

6. Give out the patterns (two sheets per student).

7. Have the students begin the activity by first writing the facts about geometry on each of the faces. The teacher should check to see that facts are complete before allowing the students to begin cutting out the patterns.

8. Assist students with the construction of the dodecahedrons.

9. When complete, have the students show their dodecahedrons and share the facts that they have written on the faces.

#### Assessments

Assess student work in the following way. This is a formative assessment:

Call on a student to share one of the facts or properties of two and three dimensional figures that he recorded. Have another student write the fact on a chart or on the board. Ask students if the fact is correct. If so, call on another student and record his fact. If not, ask students how to correct the fact and then do so. Continue until all students have had a chance to offer a property of two or three dimensional figures. Allow a few minutes for students to correct any facts that need to be corrected. Collect the figures and formatively assess them. Students who do not show that they know the properties of two and three dimensional figures need to do additional work.

If students demonstrate adequate knowledge of two and three dimensional figures, have them copy and study the chart of properties. The teacher should also make a copy. As a review, add some false statements then duplicate and give to students as a true-false review prior to a quiz.

#### Attached Files

Dodecahedron Pattern     File Extension: pdf