Purpose

In this unit students describe and classify 2D and 3D shapes. They will use their own language in their descriptions, will be exploring similarities and differences, and will be informally considering sides, corners, curved and straight lines.

Achievement Objectives

GM1-2: Sort objects by their appearance.

Specific Learning Outcomes

- Sort, compare and classify 2D and 3D objects such as triangle, square, oblong, circle, box, cylinder and sphere.
- Describe shape attributes in their own language.

Description of Mathematics

Spatial understandings are necessary for interpreting and understanding our geometric environment. The emphasis in the early years of school should include: recognition and sorting of shapes, exploration of the shapes, and investigation of the properties of the shapes.

In the van Hiele model of geometric thinking there are five levels. The first (Visualisation) is an emergent one where students recognise shapes by their appearance rather than their characteristics or properties. The second level (Analysis) is where students differentiate specific properties of shapes, for example, the number of sides a triangle has or the number of corners in a square. Students recognise certain properties that make one shape different from others. This unit is focused on this second level of the van Hiele model.

Children meet 2D and 3D shapes within their environment and there is much discussion about which is easier to consider first. Both need to be explored extensively; and opportunities given for students to communicate their findings about 2D and 3D shapes.

This unit could usefully be followed by the unit Shape explorers.

Required Resource Materials

- Mosaic tiles
- Plastic attribute blocks
- Small blocks
- String
- Geoboards and rubber bands

Activity

In this activity we sort shapes according to attributes. Working with blocks in this exploration gives students a chance to construct their own understandings about shapes and how they are related.

- Gather the students on the mat around a supply of shape blocks, mosaic tiles and attribute blocks.
*Do you see any ways that these blocks are alike? How are they alike?*

Can you see any blocks that are different? How are they different? - Use one of the categories suggested by the students to sort the blocks.
*Let’s sort the shapes by size and see how many we have.* - Put three loops of string or make chalk circles or set rings/hula-hoops out for the students to sort the blocks in.
- Begin by putting a small shape in one of the string loops.
- Distribute the shapes and have the students sort them into the three loops.
- Look at and discuss the shapes in the loops.
*Which loop has the most? Check by counting.*

Do the shapes in this loop have other things in common? - Sort the blocks using another attribute. Some possibilities are:
- colour
- shapes with 3, 4, 5 or 6 sides
- shapes that are round and shapes that aren’t.

Let the students work in small groups to sort sets of shapes in a number of different ways. Circulate among the groups encouraging the students to describe the classification used.

In this session we play a version of ‘I spy’ that helps the students focus on the shapes around them and the number of sides the shapes have.

*I spy a shape with four sides. You walk through it when you come into the classroom. What is the object?*- Have the student who guesses correctly go to the door and count the number of sides. Record this on a chart.
*I spy another object with four sides. This one we look out of. What is the object?*- Once more get the guesser to count and check the number of sides.
- Let the students take turns giving clues about a shape in the class for others to guess. Each time get the guesser to check the number of sides.
- Encourage the students to give information about the relative length of the sides of the shape. For example, all sides are the same length; this side is longer.
- After the game has been played several times get the students to draw pictures of 3- or 4-sided shapes in the room. (Alternatively you could go for a walk outside to look for shapes and then get the students to draw these.) Glue the drawings onto charts according to the way that the students classify them.
- Discuss the charts
*What are some of the things you notice about the shapes you found?*

Which did you find more of? Why do you think this is?

Do you know what we call these shapes?

Which shape is in the bag? Today we reach into feely bags to see if we can work out the shape by touch alone.

- Gather the students together in a circle on the mat. Show them 5 shapes on the floor including 2D and 3D shapes. These could be small blocks, mosaic tiles or attribute blocks.
- Show the students the feely bag.
*One of these shapes is in the bag. I wonder if you can tell me which one just by feeling it?* - Pass the bag around the circle so that each student can feel the shape. Encourage them to think about the shape. Remind them that they shouldn’t point or call out which shape they think it is so that everyone gets a chance.
- As each student feels the shape in the bag, get them to say one thing they notice about it.
*Tell me something you notice about the block in the bag.* - Once each student has had a turn to feel in the bag, ask them to say which shape they thought it was. Then reveal the hidden shape.
*Is this the shape you were expecting?* - Secretly change the shape in the bag and play again as a whole class.
- In small groups or pairs students play the game again as the teacher circulates and questions.
*Can you describe what you can feel?*

Which shape do you think it is? Why?

In this session we use the mosaic shapes as dominoes for students to explore shapes and match side lengths as they form a trail of shapes.

- Gather the students in a circle on the mat. Tip the mosaic tiles onto the mat in the middle of the circle.
- Tell them that you are going to play a game of shape dominoes. They are going to match shape sides that are the same length to make a trail around the mat.
- Let the students informally explore sides of the same length by fitting two or more shapes together.
- Place a tile on the floor and get the student next to you to choose a shape that could go next.
*Are there other ways that you could place that tile?*

Are there any ways that tile wouldn’t work? - Continue around the circle until each student has had a turn.
- The students work with a small group or a partner and continue playing the game independently, with the teacher circulating and questioning.
*What can you tell me about the shape you have chosen to go next?*

Why did you choose that shape?

In this session we use loops of string to form shapes using ourselves as the corners. We extend the idea using geoboards and by forming string shapes and sticking them onto paper.

- Gather the students on the mat.
- Have a long piece of rope or thick string and talk about the shape of the string.
*Who can tell me about this piece of string? (Long, curly, wiggly, etc.)* - Hold the string in a long straight line and then let it fall onto the floor in a muddle and get the students to describe how the shape has changed.
*What was the string like when we held it tight?*

What was it like on the floor?

How else could we hold the string or put it on the floor to change its shape? - Encourage students to make suggestions about the form of the string and to use their own language to describe it.
- Get each student to hold part of the string and get them to move backwards to form a circle using the whole class and again encourage them to describe the shape in their own language.
- Using a shorter length of string get small groups of students to hold the string and to explore the shapes that can be made.
*What sort of shapes can you make with three people? (or 4 or 5 people etc.)*

How many sides will the shape have?

Do all the sides have to be the same length? - Get the students to continue exploring string shapes in small groups as the teacher circulates and questions.
- Using rubber bands and geoboards get the students to explore the same ideas.
- Using small pieces of string each student makes a shape that they stick onto paper and bring to the mat.
- The shapes are sorted into several sets (as with Loopy Shapes, Session 1) and the students talk about the similarities and differences between the shapes they have made including, number of sides, length of sides, type of sides: curves or straight lines.
- This can be used to make a chart for display.

Home Link

Dear family and whānau,

This week we looked at objects that had the same shapes. For instance doors and windows both have four sides. We found out the names for a number of these shapes, including oblongs (rectangles), triangles and circles.

We would like you to make a list of all things that you commonly use around the home that are that are oblongs (rectangles), triangles or circles. If possible, it would be nice to put things on the list that are not found in school. Five things on each list would be plenty.