Sorting Objects by Their Features: a week of ready-to-teach maths
Five days of lessons for Year 3 Space. Print this pack and the week is prepared: each day has a one-page plan and a student worksheet, plus solid cards, rule cards, a mini-check and every answer.
Start here: five minutes to Monday
- Skim the week at a glance on the next page.
- Print the five days. Each day is two A4 sheets: a plan and a worksheet.
- Cut out the solid cards and the rule cards once; they are reused all week.
- Open the free interactive unit on your board. Every plan tells you which picture to show and which buttons to press.
- Teach straight from the plan. Timings, talk prompts, misconceptions and answers are all on the one page.
No maths background needed
This pack is written for the busy generalist teacher. A solid (a 3D object) has faces, edges and corners. The faces are its surfaces, flat or curved; an edge is where two faces meet; a corner (also called a vertex) is where edges meet. As in the interactive unit, a curved surface counts as a face, so a cylinder has three faces: two flat circles and one curved face. The big idea of the week: features explain what an object can do. Curved faces roll and flat faces stack, which is why a wheel is a cylinder and a brick is a box shape.
One day, one lesson
The five lessons fill a week of maths, one lesson of about 50 minutes a day. Run them in order: each day stands on the one before. Every plan marks a split point if your timetable runs two shorter sessions.
The week at a glance
One lesson a day for a week. Each day stands on the day before, so run them in order.
| Day | Lesson | Children learn and do | On screen |
|---|---|---|---|
| 1 | Faces, edges and corners | Name the solids, count their faces, edges and corners, and make a skeleton model | Faces, edges and corners |
| 2 | Roll or stack? | Predict and test whether objects roll, stack or do both, and explain it with flat and curved faces | Roll or stack? |
| 3 | Sort by a feature | Sort the same solids by different features, and use two hoops at once | The sorting hoop |
| 4 | Best for the job | Choose the shape that suits a job, explain why, and design an object | Best tool for the job |
| 5 | Name it and compare it | Name a solid from clues, write a riddle, and compare two solids one feature at a time | Guess the solid; Same or different? |
How the week builds
Day 1 names the solids and counts their features. Day 2 links one feature, flat or curved faces, to what an object can do, and Day 3 sorts by features. Day 4 explains why everyday objects have the shapes they do, and Day 5 names and compares solids from their features. It leans on Classifying Shapes (AC9M2SP01) and Measuring with Metric Units (AC9M3M01).
Materials for the week (one trip)
- From the classroom: scissors, pencils, two hoops or loops of string per group, this pack printed.
- A set of solids (wooden or plastic), plus a box, a can, a ball and a cone brought from home.
- Straws or pipe cleaners and playdough, for skeleton models; a board or a big book for a ramp.
- Cut out once, use all week: the solid cards and the rule cards in this pack.
Words for the word wall
solid, face, flat, curved, edge, corner, point, cube, rectangular prism, triangular prism, pyramid, cylinder, cone, sphere, roll, stack, sort, feature, rule, same, different
Dear families
This week in maths, Year 3 is looking closely at solids (3D objects): counting their faces, edges and corners, sorting them, and explaining why everyday objects have the shapes they do.
Try this at home
- Go on a shape hunt in the kitchen: find a box, a can and a ball. Which ones roll? Which ones stack?
- Count the faces, edges and corners of a cereal box together.
- Ask why a wheel is round, or why bricks are box shapes.
- Play “What am I?”: describe a solid by its features and let your child guess it.
Our shapes this week
Fill one row a day: an object you found, its shape, and why that shape suits it.
| Day | Object | Its shape | Why that shape suits it |
|---|---|---|---|
| Monday | |||
| Tuesday | |||
| Wednesday | |||
| Thursday | |||
| Friday |
Printed from the free seegongsik Sorting Objects by Their Features teaching pack · seegongsik.com/au/y3/space/AC9M3SP01/pack
Faces, edges and corners
A solid has faces (its flat or curved surfaces), edges (where two faces meet) and corners (where edges meet). A cube has 6 faces, 12 edges and 8 corners. The back of a solid is hidden, so careful counting marks each face or edge as it is counted. A skeleton model, with straws for edges and balls of playdough for corners, shows every edge and corner at once.
We are learning to
- name the cube, prisms, pyramids, cylinder, cone and sphere,
- count the faces, edges and corners of a solid,
- make a skeleton model of a solid.
Success criteria
- I can count the faces, edges and corners of a solid.
- I can make a model and say how many edges and corners it has.
You need
A set of solids, one per pair, and a cloth bag. Sticky dots or chalk. Straws or pipe cleaners and playdough. The solid cards (cut-out sheet 1). The worksheet.
Lesson flow (about 50 minutes)
| 10 min | Feely bag A child feels a solid inside the bag and describes it without naming it; the class names it and finds its solid card. Ask: “What did you feel that told you it was a cylinder?” |
| 25 min | Count them Count on the board (see the box). Pairs count the faces, edges and corners of real solids, putting a sticky dot on each face as they count it, and fill in the worksheet table. Ask: “How can you be sure you counted the faces at the back?” |
| 15 min | Make a skeleton Pairs make a cube (12 straws, 8 balls of playdough) or a square pyramid (8 straws, 5 balls) and record it on the worksheet. Ask: “Your model has 12 straws. What does each straw show?” |
Two half-sessions instead? Split after the counting; start Session B with the skeleton models.
Watch for these ideas
- Missing the faces you cannot see. Turn the solid and mark each face as you count it.
- Counting an edge twice. Run a finger along each edge and start from a marked corner.
- Thinking a cylinder has no edges. Its two circle rims are edges, where the curved face meets a flat face.
Answers
- Table (faces, edges, corners): rectangular prism 6, 12, 8; triangular prism 5, 9, 6; square pyramid 5, 8, 5; triangular pyramid 4, 6, 4; cylinder 3, 2, 0; cone 2, 1, 1.
- Models: a cube has 12 edges and 8 corners; a square pyramid has 8 edges and 5 corners. The straws are the edges, and the balls of playdough are the corners.
Faces, edges and corners
Name each solid. Count its faces, edges and corners. Use a real solid to check the back.
| Solid | Name | Faces | Edges | Corners |
|---|---|---|---|---|
Dashed lines show the edges at the back.
My skeleton model
I made a ______________________ .
It has ______ straws. They are its ______________ .
It has ______ balls of playdough. They are its ______________ .
Roll or stack?
Whether an object rolls or stacks depends on its faces. A curved face lets it roll; flat faces let it sit still and stack. A can has both: its curved side rolls, and its flat ends let it stand and stack. A cone rolls too, but around in a circle, because its curved face narrows to a point.
We are learning to
- predict whether an object will roll, stack or do both,
- test it on a ramp and in a stack,
- explain the result using flat and curved faces.
Success criteria
- I can predict whether an object will roll or stack.
- I can explain why, using its faces.
You need
A ramp for each group (a board or a big book propped on a few books). A can, a cone, a block and a ball to test, or the set of solids. The worksheet.
Lesson flow (about 50 minutes)
| 10 min | Which will roll? Hold up a ball, a box and a can. Children vote for each: rolls, stacks or both. Ask: “What about the can makes it hard to decide?” |
| 25 min | Ramp and stack test Decide on the board (see the box). Children predict for the six pictures on the worksheet, then groups test real objects on the ramp and in a stack and record what happened. Ask: “The cone rolled in a circle. Why did it not roll straight down?” |
| 15 min | Explain it Pairs explain one result to another pair, using the words flat face and curved face. Ask: “Which face did the can roll on? Which face did the box sit on?” |
Two half-sessions instead? Split after the predictions; start Session B with the ramp test.
Watch for these ideas
- Thinking a can only rolls. Stood on a flat end, it stays still and stacks.
- Saying it rolls “because it is round”. Name the curved face that does the rolling.
- Thinking a cone cannot roll. It rolls on its curved face, around in a circle.
Answers
- Pictures: a ball rolls (curved all over, no flat face); a box stacks (flat faces all round); a drum both (a curved side rolls; the flat circle ends stand and stack); an orange rolls (curved all over); a book stacks (flat faces); an ice cube stacks (six flat faces, like a cube).
- Test: a can rolls on its side and stacks on its ends: both; a cone rolls around in a circle, and will not stack; a block slides or stays on the ramp, and stacks.
Roll or stack?
Predict
Will it roll, stack, or do both? Write which faces tell you.
| Object | Rolls, stacks or both? | The faces that tell me |
|---|---|---|
a ball | ||
a box | ||
a drum | ||
an orange | ||
a book | ||
an ice cube |
Test it
Try each real object on the ramp and in a stack. Write your guess first, then what happened.
| Object | I predict | What happened |
|---|---|---|
| a can | ||
| a cone | ||
| a block | ||
| my own: ________ |
Sort by a feature
To sort, choose one feature and ask the same yes-or-no question of every solid: does it have a curved face? The same solids sort differently when the feature changes. By curved face, the cone goes with the cylinder and the sphere; by coming to a point, it goes with the pyramids. Two overlapping hoops sort by two features at once, and the cone sits in the overlap.
We are learning to
- sort solids by one feature into yes and no,
- sort the same solids again by a different feature,
- sort by two features with overlapping hoops.
Success criteria
- I can sort solids by a feature and say my rule.
- I can sort the same solids in a new way.
You need
Two hoops or loops of string per group. The solid cards and the rule cards (cut-out sheets 1 and 2), or real solids. The worksheet.
Lesson flow (about 50 minutes)
| 10 min | Guess my rule Sort a few solids into two groups without saying the rule; the class works out the rule. Ask: “What is the same about every solid in this group?” |
| 25 min | Sort it two ways Sort on the board (see the box). Groups turn over a rule card and sort the solid cards into yes and no, then turn over another rule card and sort again. Children fill in the worksheet table. Ask: “The cylinder was a yes last time and a no now. What changed?” |
| 15 min | Two hoops at once Groups overlap two hoops for “has a curved face” and “comes to a point” and place the solid cards, then fill in the hoops on the worksheet. Ask: “The cone belongs in both hoops. Where can it go?” |
Two half-sessions instead? Split after the rule-card sorts; start Session B with two hoops.
Watch for these ideas
- Changing the rule partway through a sort. Say the rule aloud and check every solid against it.
- Thinking there is only one right way to sort. The groups depend on the feature you choose.
- Leaving out a solid that does not seem to fit. Every solid is a yes or a no.
Answers
- Table (curved face, only flat faces, comes to a point): cube no, yes, no; rectangular prism no, yes, no; triangular prism no, yes, no; square pyramid no, yes, yes; triangular pyramid no, yes, yes; cylinder yes, no, no; cone yes, no, yes; sphere yes, no, no.
- Hoops: in both, cone; curved face only, cylinder, sphere; comes to a point only, square pyramid, triangular pyramid; outside both, cube, rectangular prism, triangular prism.
Sort by a feature
Yes or no?
Write yes or no for each solid.
| Solid | Has a curved face? | Has only flat faces? | Comes to a point? |
|---|---|---|---|
cube | |||
rectangular prism | |||
triangular prism | |||
square pyramid | |||
triangular pyramid | |||
cylinder | |||
cone | |||
sphere |
Two hoops at once
Write the name of each solid in the right place. Solids that fit neither rule go outside the hoops.
Best for the job
Everyday objects have the shapes they do because of what their features let them do. A wheel is a cylinder because its curved face rolls; a brick is a rectangular prism because flat faces stack with no gaps; a ball is a sphere so it rolls any way. A good explanation names the feature and what it lets the object do.
We are learning to
- choose the solid that suits a job,
- explain the choice with a feature, using “because”,
- design an object for a job and explain its shape.
Success criteria
- I can choose the best shape for a job.
- I can explain my choice with a feature.
You need
A few everyday objects: a can, a box, a ball, a pencil. Playdough. The worksheet.
Lesson flow (about 50 minutes)
| 10 min | Why this shape? Hold up each object in turn; children say why it has its shape. Ask: “Why are cans not made as spheres?” |
| 25 min | Match the job Choose on the board (see the box). Children choose a solid for each job on the worksheet and finish the sentence with “because”. Ask: “Does this job need rolling, stacking or standing firm?” |
| 15 min | Design it Children design a pencil holder: choose a solid, draw it and explain why. Pairs make it from playdough. Ask: “What would go wrong if your pencil holder were a sphere?” |
Two half-sessions instead? Split after matching the jobs; start Session B with the design.
Watch for these ideas
- Choosing a favourite shape. Ask first what the job needs the object to do.
- A reason with no feature, such as “because it is good”. Name the face or point that helps.
- Thinking only one shape could work. Some jobs suit more than one; the reason is what counts.
Answers
- Jobs: a rolling pin, cylinder, because its curved face rolls along the dough; a brick for a wall, rectangular prism, because its flat faces sit flat and stack with no gaps; a marble, sphere, because it is curved all over, so it rolls any way; a funnel, cone, because its wide top narrows to a point, to pour into a small hole.
- Pencil holder: a cylinder or a rectangular prism, open at the top, because a flat base stands still on the desk. A sphere or a cone would roll or tip over.
Best for the job
Match the job
Choose a solid from the list for each job. Finish the sentence.
Solids: cube rectangular prism cylinder cone sphere square pyramid
| Job | Best solid | It suits the job because ... |
|---|---|---|
| a rolling pin | ||
| a brick for a wall | ||
| a marble | ||
| a funnel |
Design a pencil holder
Choose a solid for a pencil holder. Draw it, then explain why its features suit the job.
My pencil holder is a ______________________ because
Name it and compare it
A few features can name a solid: 6 square faces, 12 edges and 8 corners can only be a cube. Comparing works best one feature at a time. A cube and a rectangular prism have the same number of faces, edges and corners, so they are the same on those features, but a cube’s faces are all squares.
We are learning to
- name a solid from a list of its features,
- write clues that name a solid,
- compare two solids one feature at a time.
Success criteria
- I can name a solid from clues.
- I can say how two solids are the same and how they are different.
You need
The solid cards and the rule cards (cut-out sheets 1 and 2). The worksheet. The unit’s self-check quiz.
Lesson flow (about 50 minutes)
| 10 min | Riddles Solve riddles on the board (see the box), then children solve the four riddles on the worksheet. Ask: “Which clue told you it could not be a cube?” |
| 25 min | Same and different Compare pairs on the board. Children fill in the compare table; pairs then turn over two solid cards and a rule card and decide same or different, and write a riddle for each other. Ask: “A cube and a box both have 6 faces. How are they different?” |
| 15 min | Class quiz Run the self-check quiz as a team game: teams hold up one, two or three fingers for their choice. Ask: “Which picture from this week would prove that answer?” |
Two half-sessions instead? Split after the riddles; start Session B with same and different and the quiz.
Watch for these ideas
- Naming a solid from the first clue. Check every clue before deciding.
- Comparing two features at once. Name the one feature being compared.
- Thinking a cube and a rectangular prism are the same solid. A cube’s faces are all squares.
Answers
- Riddles: 1 triangular prism, 2 triangular pyramid, 3 rectangular prism, 4 square pyramid.
- Compare: cylinder and cone, number of flat faces: different (2 and 1); cube and square pyramid, has a square face: same (yes and yes); sphere and cylinder, can roll: same (yes and yes); rectangular prism and triangular prism, number of corners: different (8 and 6).
- A riddle: any clues that fit only one solid.
Name it and compare it
What am I?
- I have 5 faces: 2 triangles and 3 rectangles. I have 9 edges and 6 corners.
I am a ______________________ . - I have 4 faces, and they are all triangles. I have 6 edges and 4 corners.
I am a ______________________ . - I have 6 flat faces, 12 edges and 8 corners, and my faces are not all squares.
I am a ______________________ . - I have 5 faces: a square and 4 triangles. I come to a point.
I am a ______________________ .
Same or different?
Look only at the feature named. Write same or different.
| The two solids | The feature | Same or different? |
|---|---|---|
| cylinder and cone | number of flat faces | |
| cube and square pyramid | has a square face | |
| sphere and cylinder | can roll | |
| rectangular prism and triangular prism | number of corners |
Write a riddle
Choose a solid. Write three clues about its features, so that only that solid fits.
Solid cards
Cut out the eight cards, one set per group. They are used all week: to name the solids on Day 1, to sort in hoops on Day 3, and for riddles and comparing on Day 5. Dashed lines show the edges at the back.
Rule cards
Cut out the twelve cards. On Day 3, a group turns over a rule card and sorts the solid cards into yes and no. On Day 5, pairs turn over two solid cards and a rule card and decide whether the two solids are the same or different on that rule.
Teacher note, the yes solids: has a curved face: cylinder, cone, sphere; has only flat faces: cube, rectangular prism, triangular prism, square pyramid, triangular pyramid; comes to a point: square pyramid, triangular pyramid, cone; can roll: cylinder, cone, sphere; can stack: cube, rectangular prism, triangular prism, cylinder; has a square face: cube, square pyramid; has a triangle face: triangular prism, square pyramid, triangular pyramid; has a circle face: cylinder, cone; has 8 corners: cube, rectangular prism; has no corners: cylinder, sphere; has 12 edges: cube, rectangular prism; has 5 faces: triangular prism, square pyramid.
What we know: Sorting Objects by Their Features
Work on your own. You may use the real solids.
- Name the solid in the picture: ______________________
- How many corners does it have? ______
- Will a cylinder roll, stack, or do both? ______________ Why? ______________________________
- Circle the solids that have a curved face: cube · cone · sphere · rectangular prism · cylinder
- Sort by “comes to a point”. Which of these say yes? cone, cube, square pyramid, cylinder: ______________________
- Why is a ball made as a sphere? ______________________________________
- I have 8 edges and 5 corners, and one of my faces is a square. What am I? ______________________
- Compare a cube and a rectangular prism on the number of edges. Same or different? ______________
Answers and marking guide
Answers
- A triangular prism.
- 6.
- Both: its curved face rolls, and its flat circle faces let it stand and stack.
- cone, sphere, cylinder.
- cone and square pyramid.
- It is curved all over, so it rolls any way.
- A square pyramid.
- Same: both have 12 edges.
A quick three-level guide
| Idea | Working towards | At standard | Beyond |
|---|---|---|---|
| Features (Q1, Q2, Q7) | names some solids; counts features with gaps | names the solids and counts faces, edges and corners | names a solid from its features and writes clues for one |
| Sorting and comparing (Q4, Q5, Q8) | sorts by how a solid looks, or changes the rule | sorts by a stated feature and compares one feature at a time | sorts the same solids two ways and uses overlapping hoops |
| Features and uses (Q3, Q6) | says what an object does, without a reason | explains rolling and stacking with flat and curved faces | chooses and explains a shape for a new job |
Eight questions, three ideas. A child at standard explains what an object can do by naming its flat and curved faces, not just its shape name.
Weekly class record
Jot a tick as you move around the room; the mini-check fills any gaps. A tick a day is plenty.
| Name | Faces, edges, corners | Roll or stack | Sorts by a feature | Shape and use | Names, compares |
|---|---|---|---|---|---|
The five columns are the five days: faces, edges and corners, rolling and stacking, sorting by a feature, shape and use, and naming and comparing.