Introduction

Learning About®... GeoSolidsTM is a resource providing hands-on activities and ideas that allow you, the teacher, to lead students in an active exploration of the world of mathematics. The activities presented involve students in the process of exploring abstract concepts through the use of manipulatives. Students are encouraged to think critically, plan strategy, and share conclusions. Learning About ... GeoSolids emphasizes— n communication n exploration n problem solving n analysis The Basic GeoSolids Set consists of the following six shapes: , , sphere, cone, triangular , and pyramid. The twelve-piece GeoSolids Set consists of a cube, a cone, two rectangular prisms (one square), two , a hemisphere, a sphere, a pyramid, a , a , and an octagonal prism. GeoSolids can be used to— n explore which flat shapes are part of the solid figures n identify attributes such as the number of faces, corners, and edges n discover which shapes can slide, roll, or stack Exploring with GeoSolids Students at all grade levels should be allowed time to freely explore and experiment with GeoSolids before guided activities begin.

Introducing geosolids

Group Size: Whole Class Procedure: Display the set of GeoSolids. Note: Teachers of kindergarten through grade 2 may wish to initially display only two or three geometric solids–cube, cylinder, and sphere. The prism, cone, and pyramid may be introduced at a later date. Hold up the sphere. Describe and name the shape. Use clues about its attributes.

n This shape is a sphere. (Primary students may identify this shape as a ball.) n The sphere is round and it can roll.

2 Invite students to identify classroom objects that have the same shape. [ball, globe, etc.] Hold up the cube. Describe and name the shape. Use clues about its attributes. n This shape is a cube. (Primary students may identify this shape as a box.) n The cube has flat sides and corners. It cannot roll. Challenge students to identify classroom or household objects that have the same shape. Hold up the cylinder. Describe and name the shape. Use clues about its attributes. n This shape is a cylinder. (Primary students may identify this shape as a can.) n The cylinder has 2 flat sides. It has no corners. The cylinder can roll. Challenge students to identify classroom or household objects that have the same shape. Continue this activity for the cone, pyramid, and triangular prism. Additional information regarding the set of twelve GeoSolids: Hold up the sphere and hemisphere. Name the shapes and describe them, using clues about their attributes. n This shape is a sphere. The sphere is round and it can roll. n This shape is a hemisphere. The hemisphere has one flat side. Write the prefix “hemi” on the chalkboard. Explain that this prefix indicates half of something. n How are the sphere and hemisphere alike or related? [Answers will vary. The hemisphere is half of the whole sphere.] Hold up the two cylinders. Name and describe the shape. Use clues about their attributes. n These shapes are cylinders. n Each cylinder has two flat sides. The cylinder has no corners. The top and bottom of the cylinder are circles. A cylinder can roll. n How are the cylinders alike? Different? [Answers will vary. Both have the same shape. One cylinder is tall and narrow. The other cylinder is short and wide.] Continue this activity for the cube, cone, and pyramid. Describe and name the shapes. Use clues about their attributes. Hold up the two rectangular prisms. Name and describe the shapes. n These shapes are rectangular prisms. Each prism has flat sides. The sides meet to form corners. A rectangular prism cannot roll. n How are the rectangular prisms alike? different? [Answers will vary. Both have the same shape. One prism is tall and narrow. The other prism is short and wide.] Hold up the triangular prism. Name and describe the shape. Use clues about its attributes.

3 n This shape is a triangular prism. It has flat sides. The sides meet to form corners. It cannot roll. Write the prefix “tri” on the chalkboard. Challenge students to define the prefix. “Tri” means three. n Why is the prefix “tri” meaningful in identifying this prism? [The two flat ends of this prism are in the form of a three-sided shape or triangle.] Hold up the hexagonal prism. Name and describe the shape. n This shape is a hexagonal prism. It has flat sides. It does not roll smoothly. Write the prefix “hexa” on the chalkboard. Explain that this prefix means six. n Why is the prefix “hexa” meaningful in identifying this prism? [The two ends of this prism are in the form of a six-sided shape or hexagon.] Hold up the octagonal prism. Name and describe the shape. n This shape is an octagonal prism. It has flat sides. The sides meet to form corners. This prism does not roll smoothly. Write the prefix “octa” on the chalkboard. Explain that this prefix means eight. n Why is this prefix meaningful in identifying this prism? [The two ends of this prism are in the form of an eight-sided shape or .]

Shape match

Challenge students to identify classroom or household objects that have the same shape as the GeoSolids.

Group Size: Whole Class or Small Groups Materials: GeoSolids; classroom or household objects in the shapes of the GeoSolids — cans, chalk, paper towel tubes, boxes, number , paper cones, etc; large paper bag Procedure: Hold up each GeoSolids shape. Identify the solid by name. Invite students to describe the shape and attributes of the solid. After each solid is identified and described, place it in the paper bag. Hold up a cardboard tube (paper towel type). Ask a student volunteer to describe the attributes of the tube. [It can roll. It is round and long.] Invite another student to reach into the paper bag containing the GeoSolids. Using only the sense of touch, the student is to find the matching solid. [cylinder] Have students take turns matching common objects to the GeoSolids in the paper bag. Encourage students to describe the attributes of the common object and the GeoSolids shape that make a match.

4 corners and sides

Group Size: Small Groups Procedure: Provide a set of GeoSolids for each group of students.

n What do you think of when you hear the words corner and side? [Answers will vary.] Provide an opportunity for each group of students to closely examine the GeoSolids. Encourage students to group the solids according to similarities. Invite a volunteer from each group to present the findings of the group.

n How are the GeoSolids shapes alike and how are they different? [Answers will vary.]

n Which shapes have flat sides? [For the set of six — cube, triangular prism, cylinder, cone, and pyramid. For the set of twelve — cube, rectangular prism, cylinder, cone, pyramid, hemisphere, hexagonal prism, octagonal prism, and triangular prism.]

n Which shapes have corners? [For the set of six — cube, triangular prism, and pyramid. For the set of twelve — cube, rectangular prism, pyramid, hexagonal prism, octagonal prism, triangular prism.] Create the following chart on the chalkboard. List the solids contained in your set.

Solid Corners Flat Sides cube [8] [6] triangular prism [6] [5] cylinder [0] [2] cone [0] [1] pyramid [5] [5] sphere [0] [0] hemisphere [0] [1] rectangular prism [8] [6] hexagonal prism [12] [8] octagonal prism [16] [10]

Hold up each GeoSolids shape individually. Ask students to describe the solid, making note of the number of corners and flat sides. Fill in the chalkboard chart. Encourage students to name a classroom or everyday object that is an example of each solid.

5 roll and stack

Group Size: Small Groups Procedure: Provide a set of six GeoSolids shapes for each group of students– cube, sphere, triangular prism, cylinder, cone, and pyramid. Allow students a few minutes to freely explore the solids. Encourage students to move the shapes, feel them, and discover how the shapes are alike and different.

n How can we tell if a solid can be stacked? [Students may employ various strategies. A solid needs to have at least two parallel flat sides in order to stack.]

n Which of the GeoSolids can be stacked? [cube, triangular prism, cylinder]

n Which of the GeoSolids can roll? [cylinder, sphere, cone]

n Why do these solids roll? [They have curved surfaces.] Create the following chart on the chalkboard. Call on student volunteers to demonstrate the stacking and rolling attributes of each GeoSolids shape. Solid Stack Roll cube [yes] [no] triangular prism [yes] [no] cylinder [yes] [yes] cone [no] [yes] pyramid [no] [no] sphere [no] [yes]

Solids riddles

Group Size: Whole Class or Small Groups Procedure: Provide a set of six GeoSolids shapes to be placed on classroom display or provide a set of solids – cube, cylinder, sphere, cone, triangular prism, and pyramid – for each group of students. Hold up each solid and challenge students to name an everyday or classroom object that matches the shape of the solid.

n sphere [globe, ball...] n cube [box, carton...] n cylinder [oatmeal box, 35-mm film canister...] n cone [ice cream cone, coffee filter...] n triangular prism [napkin holder, gift box...] n pyramid [tent, pyramid structure...] Challenge your students to name the solids from the following descriptions.

6 n I am a solid that cannot roll. All my sides are the same size. I am the _____. [cube]

n I am a solid that can roll. I have no corners and no flat sides. I am the _____. [sphere]

n I am a solid that can roll. I have two flat sides. I have no corners. I am the _____. [cylinder]

n I am a solid that can be stacked. I cannot roll. I have eight corners and six sides. My sides are not all the same size. I am the ____. [rectangular prism]

n I am a solid that cannot be stacked or rolled. I have five corners and five flat sides. I am the ____. [pyramid]

n I am a solid that cannot be stacked. I have only one flat side. I am the _____. [cone] Challenge students to create their own riddles. The riddles can be presented either to small groups or to the whole class. Encourage students to incorporate Flat shapes information about stacking, rolling, sides, and corners in the clues they create. When appropriate, encourage students to create riddles using all twelve GeoSolids. Direct students to be very specific in creating clues. Group Size: Small Groups Materials: Set of GeoSolids, paper, and pencils for each group of students Procedure: Allow students a few minutes to freely explore the GeoSolids. Review the name of each GeoSolids shape. Draw the following flat shapes on the board. square rectangle circle triangle If you are using twelve GeoSolids, add the following flat shapes. hexagon octagon Review the attributes of the flat shapes. square [4 sides, all equal] rectangle [4 sides–2 long sides, 2 short sides] circle [0 sides, round] triangle [3 sides] hexagon [6 sides] octagon [8 sides] Direct students to place the flat side of each GeoSolids shape on a sheet of paper.

7 Instruct students to trace around the solid to make an outline of the flat side. Have students identify the flat shape created by each solid. n Which solids have a flat side that is a circle? [Set of six — cone and cylinder. Set of twelve — cone, cylinder, and hemisphere.]

n Which solids have a flat side that is a square? [cube, pyramid, and short rectangular prism]

n Which solids have a flat side that is a rectangle? [rectangular prism, octagonal prism, hexagonal prism, and triangular prism]

n Which solids have a flat side that is a triangle? [pyramid and triangular prism]

n Which solid has a flat side that is a hexagon? [hexagonal prism]

n Which solid has a flat side that is an octagon? [octagonal prism]

n How are the GeoSolids and flat shapes alike? [Answers will vary. The flat side of a GeoSolid is a flat shape. GeoSolids and flat shapes both have corners. The sphere is the only solid with no corresponding flat shape or corners.]

n How are the GeoSolids and flat shapes different? [Answers will vary. GeoSolids can stack and roll. The flat shapes cannot roll.]

Group Size: Whole Class FEEl a solid

Materials: Geometric Solids, scarf or blindfold, and paper or cloth bag Procedure: Hold up each solid individually. Call on students to name the particular solid and identify the attributes of each solid. (For example: the cube has six flat sides, eight corners, can be stacked, cannot roll.) Blindfold student volunteers. Ask the students to identify a solid using only the sense of touch. Direct the students to describe what they feel. They should explain how they know which figure they are touching. Place four solids into a paper or cloth bag. Name a particular solid. Call on students to reach into the bag. Using only the sense of touch and their knowledge of a particular solid’s shape and attributes, students are to pick the named solid out of the bag. Emphasize that students are to use identifying attributes to distinguish each particular GeoSolid. Group Size: Pairs

8 volume

Materials: Cube, Rectangular Prism, Base Ten Unit Blocks Procedure: Provide a Cube, Rectangular Prism, and 20–30 Base Ten Unit Blocks for each student pair. Write the following on the chalkboard: The volume of a cube or rectangular prism is the number of cubic units that fit inside the solid. Volume is often stated using the cubic inch (in3) or the cubic foot (ft3). One student in each pair is to build a cube or rectangular prism using the Base Ten Unit Blocks. The other student is to count the blocks used and state the volume. Each student should have at least two opportunities to build and two opportunities to calculate volume. Write the following on the chalkboard: To find the volume of a cube or rectangular prism, multiply the length, the width, and the height. V = l x w x h Direct students to once again build cubes and rectangular prisms using the Base Ten Unit Blocks. One student is to build a solid. The other student in the pair is to calculate the volume, using the algorithm V = l x w x h. Both students are to count the actual unit blocks to check the correct volume.

Note: A rectangular prism whose faces are all congruent squares is a cube. Group Size: Small Groups FAce, edge, and vertex

Procedure: Provide a set of GeoSolids for every group of students. Allow students a few minutes to freely explore the solids. Review the name of each GeoSolids shape. Write the following on the board: A flat side of a solid is called a face. A corner of a solid is called a vertex. Two faces of a solid meet at an edge. The edge forms a line segment. Create the following chalkboard chart. List only the solids contained in your set. Direct students to use the GeoSolids as aids in filling in the chart. Solid Faces Edges Vertices

9 cube [6] [12] [8] triangular prism [5] [9] [6] pyramid [5] [8] [5] cylinder [2] [0] [0] cone [1] [0] [1] sphere [0] [0] [0] hemisphere [1] [0] [0] rectangular prism [6] [12] [8] hexagonal prism [8] [18] [12] octagonal prism [10] [24] [16]

n What geometric shape are the six faces of a cube? [square] n What geometric shape are the two faces of a cylinder? [circle] n What geometric shape are the six faces of the short rectangular prism? [rectangle] n What geometric shape are the two end faces of the tall rectangular prism? [square]

Note: A square is a rectangle with four congruent sides.

n What geometric shape is the one base face of a pyramid? [square] n What geometric shape are the four other faces of a pyramid? [triangle] n What geometric shape are the end faces of the triangular prism? [triangle] n What geometric shape are the other faces of the triangular prism? [rectangle] n What geometric shape is the face of the hemisphere? [circle] n What geometric shape are the two end faces of an octagonal prism? [octagon] n What is the geometric shape of the other eight faces of an octagonal prism? [rectangle] n What geometric shape are the two end faces of a hexagonal prism? [hexagon] n What is the geometric shape of the other six faces of a hexagonal prism? [rectangle] n The flat side of a geometric solid is called a _____ . [face] n Two faces meet at an _____ . [edge] n Three edges meet at a _____ . [vertex]

Ask a volunteer to choose a GeoSolids shape. The student is then to locate an object in the room that has the same shape as the solid. The faces, vertices, and edges of the object identified are to be highlighted.

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