3.4.6
Introduc#on Students will describe the features of three-­‐dimensional objects, and create three-­‐dimensional models. Resources •  3D objects: cone, cube, cylinder, sphere, prisms, pyramids. •  Whiteboards and washable pens. •  Polydrons •  Straws •  Srings •  Scissors Ac#vity Process-­‐Straw and String Construc#on 1.  Ask students to work in pairs. 2.  Ask each pair to make a triangle, rectangle or square. Straws can be cut to make triangles with sides of different lengths and to make different rectangles All shapes are make by threading the string down the centre of the straws and tying a knot to finish the shape. Only one straw is used on each edge. 3.  Ask students to look at the shapes make and discuss all the things that are the same and different about their shapes. Australian Curriculum Year Three ACMMG063 Make models of three-­‐dimensional objects and describe key features. Proficiency Strand: Problem Solving – making models of 3D objects Ac#vity Process – Nets 1.  Using the polydrons, ask students to create a 3D shape 2.  Ask students to carefully open up their shape and lay it flat to see what the net looks like. 3.  Discuss which shapes the faces are that are required to create the 3D object. 4.  Discuss the corners and edges of the 3D object and how they were created. For example: the edge is where two 2D shapes meet. 5.  Ask students to create a different net for the same 3D object. 7.  Repeat making other 3D objects. Source: Marj Horne, ACU.2010 Time / Classroom Organisa#on Each acKvity process may be introduced in a small or whole group context. Allow 20-­‐25 minutes for each part of this acKvity. Use every opportunity to idenKfy and describe the properKes of 3D objects in the environment. Word Wall: net, 3D objects, cone, cube, cylinder, sphere, prisms, pyramid, aQributes, same and different, parallel, sides, parallelogram, rhombuses, predict
4.  Students should noKce that triangles do not have parallel sides but that rectangles and squares do. 5.  Students should also noKce that rectangles and squares do not stay as rectangles and squares but can move dynamically to show a range of parallelograms and rhombuses. 6.  Ask students to look at the shapes that they have made: triangle, square, rectangle, parallelogram, rhombus and decide where each shape can be wriQen in the table below. Has parallel sides Does not have parallel sides Has perpendicular sides Does not have perpendicular sides Source: Marj Horne, ACU.2010
Ac#vity Process – Net Crea#on 1.  Provide students with a collecKon of 3D objects 2.  Ask students or groups to select a object and predict what the shapes net would fold out to be. 3.  Ask students to draw to scale the predicted net for the 3D object. 4.  Ask students to fold their net up to see create their predicted 3D object. 5.  Discuss with students the success of their 3D object, analysing the what correcKons may need to be made to their created net. 6.  Repeat with a different 3D object. Varia#ons & Extensions 1.  Pyramid Resources: square-­‐based pyramid model, paper Display a model of a square-­‐based pyramid. Ask students to draw all the possible nets for a square-­‐
based pyramid. Ask: How are they the same? How are they different? Source: First steps in MathemaDcs – Space, 2009. Rigby: Port Melbourne. p77 2.  Dice Resources: Dice, dice net Provide students with a dice and a net of a cub. Ask students to place the dots on the cube net so that when it is folded the dots will be in the exactly the same place as on the dice. Ensure that students focus on the posiKon of the dots in relaKon to each other in the dice. Ask: How can you be sure the dots are in the right spot on your net? Source: First steps in MathemaDcs – Space, 2009. Rigby: Port Melbourne. p78 3.  Coloured Cube Resources: CollecKon of different cube nets, cubes Give each student a cube with each face coloured a different colour and a collecKon of nets. Invite students to visualise where the colours would be on each face of the net and colour them accordingly. Encourage them to fold the net to check their predicKons. Ask: What part of the net did you colour first? Does the order in which you colour maKer? Why? Source: First steps in MathemaDcs – Space, 2009. Rigby: Port Melbourne.p79 Digital Resources hQp://www.sadlier-­‐oxford.com/math/enrichment/gr4/EN0411b/
EN0411b.htm hQp://au.ixl.com/math/year-­‐3/nets-­‐of-­‐3-­‐dimensional-­‐figures Contexts for Learning Play: Allow students Kme to play with and create polydron shapes. InvesKgaKon: Skeleton Cube: Using newspaper and masking tape ask students to build a skeleton cube the height of their school desks. Ask students: Would this support your weight? How can you modify the cube to make it stronger? Source: First steps in MathemaDcs – Space, 2009. Rigby: Port Melbourne. P 179 Real life experience: When students are playing or creaKng board games ask them to create their own dice. This may be a standard 6 sided cube or they may invent an 8 sided dice! RouKnes and TransiKons: 3D shape flash cards – When transiKoning hold up flash cards and ask students to tell you the number of faces/edges/
corners etc. Assessment As the students are building the shapes take the opportunity to ask them specifically about the shape that they are making (or have made). Does it have any parallel edges? Does it have any parallel faces? How do you know? Does it have any perpendicular edges? Use the opportunity in the discussion to note the language the students are using. Source: Marj Horne, ACU 2010. Achievement Standard: make models of 3D objects Background Reading IdenKfying an object by using the sense of touch rather than sight can assist children to visualise the shape through its properKes. This task also requires the use of language to connect the visual picture with properKes of shapes. A cube has 6 flat square faces. All faces are the same size; 8 corners (verKces); 12 edges. A sphere has one curved round surface. It is a perfectly round 3D shape like a ball. A cylinder has two ends which are parallel to each other. Each end is exactly the same size circular shape; no corners (verKces); 2 flat faces; 2 edges. A cone has a flat circular base; sides are curved; 1 edge; top is pointed and is called an apex. A rectangular prism has 6 flat rectangular faces; 8 corners (verKces); 12 edges. A square pyramid is a space figure with a square base and 4 triangle-­‐shaped sides. A triangle pyramid (or tetrahedron) is a 4-­‐sided space figure. Each face of a tetrahedron is a triangle. Year three NAPLAN Numeracy test links •  3D objects – properKes •  3D objects – view, flip, slide, turn, nets Links to Related MAGs 3.2.8 – 3D Objects 1 2.3.9 – 3D Objects 1.3.9 – 3D Objects