In this unit students investigate the features of solid shapes and learn the names for them. They will be introduced to making nets for 3D shapes.
- Explore and describe faces, edges, and corners of 2D and 3D objects.
- Make, name and describe polygons and other plane shapes.
This unit explores basic solid objects by allowing the students to play with them in a structured way. The end product of the exploration is the construction of nets. All of the activities here will strengthen the students' concepts of 3D objects and their attributes, as well as their understanding and use of geometrical terms and language. This knowledge will be a foundation for work at Levels 3 and 4, where more sophisticated definitions of shape are used (Te Whanau Taparau - The Polygon Family).
- Solid shapes (cubes, rectangular prisms, triangular prisms, and cylinders)
Session 1: Packages
In this activity we investigate the features of 3D shapes using packaging as examples. You will need to collect a variety of packages to carry out these activities. If you have time, the packages could be covered in old wrapping paper or wrapped in plain paper and addressed to pairs or groups of three students. Unwrapped packages would work as well.
- Put a variety of cardboard packages into a pillowcase (this could be a pretend mailbag.) Gather the students on the mat and tell them that you have a variety of parcels in your bag. Ask a student to select a parcel from the pillowcase. As a class, ask the students to describe the parcel to you. Record their responses, focusing on key words that they give you. For example, the packet has 8 corners, it has a square face, and it has straight edges.
- Put the students into pairs and get one person from each pair to select a parcel from the pillowcase.
- In pairs the students draw their parcel and describe the features as above. These descriptions are recorded with the drawing and are shared with the class.
- Record all the mathematical words used to describe the packages.
- If the packages were wrapped ask the students to guess what might be in their package. Wrapped parcels could then be unwrapped.
Session 2: Solids
In this activity students will investigate the properties of 3D shapes further by considering the faces of the shapes. You will need solid 3D shapes for the students to explore i.e. cubes, rectangular prisms, triangular prisms, and cylinders.
- Revise the use of the packaging descriptions from Session 1 by modelling an example using the words from your vocabulary chart.
- Introduce the solid shapes e.g. the cubes, rectangular prisms, triangular prisms etc. Hand these out for students to feel and explore. Get students to describe their 3D shape to a buddy, encouraging them to use the vocabulary on the chart.
- Give students a 3D solid shape and ask them to trace around the faces to investigate the shapes of the faces of their shape.
- Ask students to write a description of the drawings using the maths vocabulary.
- Students could then create their own designs, e.g. Robots, by drawing around the faces of the 3D solid shapes.
- Work with the students to develop a chart with a picture of the 3D solid, names of the 3D solid, number of edges and faces.
Session 3: Solids’ Faces
In this activity students will try to identify 3D solid shapes from drawings of the faces of these solids. This involves pairs of students playing a game. Students will work in pairs to draw the faces of 3D solid shapes. They will then try to identify the solid shapes by matching the drawn faces to the solids.
- Hand out a collection of solid shapes to each pair, for example, a cube, a rectangular prism, a cylinder, etc.
- In pairs, students are to trace all of the faces of 1 solid shape onto a single sheet of paper.
- Partners swap sheets with another pair. The other pair has to match the solids with the drawings of the faces. Pairs then check guesses.
Session 4: Netting
In this activity students will be exploring making a net from solid shapes by drawing around 3D solid shapes as they roll it along a piece of paper.
- Working in pairs, students select a solid shape to "unwrap".
- Students unwrap the solid by rolling the shape and tracing the faces as they roll. Remember to roll the shapes sideways as well. Students could then investigate how many different nets they can make with their shape by rolling the shape in different ways. The result should resemble a net for the shape.
- Students cut out the nets for the shape and fold them together to establish which design makes their solid shape. They may need support to fold along the lines that they have made.
- Conclude the session by giving the students a package from Session 1 to carefully unpack to form a net. Look at the similarities and differences between the packages and the drawn nets.
- Display the packages that have been unpacked as nets.
Session 5: Foil covers
In this session students make a cover for their solid shape.
- Begin this session by sharing the nets drawn from the 3D solid shapes. Discuss the similarities and differences between the net designs. Use the vocabulary chart to support the discussion. Encourage students to use these words.
- Give students a piece of foil to wrap around their shape. Press the foil tightly around the shape. Put pressure onto the foil to ensure it tightly wraps around the shape.
- Carefully cut along the edges of one of the faces of the shape. Cut only as many edges as you need to, to be able to remove the solid from the inside of its foil cover.
- Reassemble the foil to make the original shape.
- Students may want to make more than one solid shape.
- Foil shapes could be stuffed with something to give them more structure.
- Make a display of the foil solids. Make sure the names of the solids are clearly labelled
Session 6: A Collection of Solids
In this session students will find practical examples of 3D shapes by making a display that categorises 3D shapes. Link this activity to the homework activity.
- Ask students to collect pictures of examples of 3D shapes from magazines, junk mail or websites.
- Stick these onto individual charts that have been labelled for each solid.
- Display this with the foil models.