Tricky Bags

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This unit comprises 5 stations, which involve ākonga developing an awareness of the attributes of volume and mass. The focus is on development of the language of measurement.

Achievement Objectives
GM1-1: Order and compare objects or events by length, area, volume and capacity, weight (mass), turn (angle), temperature, and time by direct comparison and/or counting whole numbers of units.
Specific Learning Outcomes
  • Push, pull, lift and handle objects in order to become aware of mass.
  • Compare masses by pushing and lifting.
  • Pack materials and fill containers.
  • Pour liquids from and into containers.
Description of Mathematics

Early experiences must develop an awareness of what mass is, and of the range of words that can be used to describe it. A mass needs to be brought to the attention of many ākonga attention as it is not an attribute that can be seen. They should learn to pick up and pull objects to feel their heaviness. Initially, young ākonga might describe objects as heavy or not heavy. They should gradually learn to compare and use more meaningful terms (e.g. lighter and heavier).

As with other measures, ākonga require practical experience to begin forming the concept of an object taking up space. This can be developed through lots of experience with filling and emptying containers with sand and water. Pouring experiences that make use of containers of similar shapes and different capacities (and vice versa), are also important at this stage. They also need to fill containers with objects and build structures with blocks. The use of language such as: it’s full it’s empty! There’s no space left! It can hold more! focus attention on the attribute of volume. The awareness of the attribute of volume is extended as comparisons of volume are made at the next stage.

The stations may be taken as whole class activities (fostering mahi tahi - collaboration) or they may be set up as group stations for ākonga to explore (fostering tuakana-teina - peer learning). We expect that many young ākonga will already be aware of the attributes of volume and mass. For them, these may be useful learning-through-play activities.

Opportunities for Adaptation and Differentiation

The learning opportunities in this unit can be differentiated by providing more support or challenge to ākonga. For example:

  • consider stations that would work best as whole class lessons and which stations could be more suitable for ākonga to explore in small groups or pairs - both of these models could support and/or challenge ākonga
  • in station 1 and 2 increasing the challenge by asking ākonga to order three of more bags/cartons by mass
  • providing recording material (paper, whiteboards, photo-taking or voice recording devices) for ākonga to record their thinking as they complete these stations
  • displaying some measuring tools around the classroom that ākonga could explore and use to help measure volume and mass (for example, scales, rulers, balance scales and suitcase scales - these could be digital or analogue).

The measuring activities in this unit can be adapted to use objects that are part of your ākonga everyday life.  For example:

  • in session 1 compare the mass of ākonga backpacks, lunchboxes or book bags  
  • in session 3 replace The Three Bears with another story that has characters with different sized 'appetites', that is popular with your ākonga (e.g. Peppa, George and Daddy Pig).
  • where possible, discuss experiences of volume and mass that your ākonga may have experienced, for example, building construction of a new marae, filling the kura swimming pool or sandpit, or carrying heavy pukapuka back to the library.

Te reo Māori vocabulary terms such as papatipu (mass), kahaoro (volume), taumaha (heavy) and taimāmā (light) could be introduced in this unit and used throughout other mathematical learning.

Required Resource Materials
  • Session 1: Reusable supermarket bags, books
  • Session 2: cartons or boxes filled with blocks (varying masses), chart paper
  • Session 3: Paper or light card, popcorn
  • Session 4: Paper cups, beans, containers (varying sizes and shapes), water tray
  • Session 5: Book corner

Session 1: Tricky bags

In this activity we investigate bags that look the same, but one is empty and the others are filled with books.

  1. Display the bags for ākonga to see.
    Are these bags the same or different?
    How do you know?
    Are you sure?
  2. If no one suggests looking in the bags or lifting them, ask for two ākonga to lift a bag each and describe what they feel. List the words that they use on the board.
  3. Let other ākonga lift the bags and give their description.
  4. Give pairs of ākonga two supermarket bags and ask them to make up their own 'tricky bags'.
  5. Let ākonga share their tricky bags with other pairs of ākonga. Remind them to describe what the bag feels like when they lift it.
    Can you guess by just looking, which is heavy?

Session 2: Push and Pull

In this activity we push and pull objects to see which feels heavier.

  1. Show ākonga two large cartons. Each carton should be filled with heavy blocks or books that ākonga can't lift easily - they should all vary in mass. 
    Are these cartons the same or different?
    How do you know?
    Are you sure?
    How could you find out?
  2. If this activity has followed from the tricky bags activity you would expect ākonga to suggest that they lift the cartons. Tell ākonga that the cartons are too large to lift, and ask if they could think of another way of comparing them.
    The cartons are too large for you to lift safely. Can you think of another way of finding out how heavy they are?
  3. Let ākonga take turns pushing or pulling the cartons.
    Do you think they are the same?
    Why? Why not?
    Which carton is heavier? How do you know?
  4. Discuss objects that ākonga have seen being pushed or pulled rather than lifted. For example: beds, tables, couches, pianos, vehicles that have broken down, objects at construction sites.
  5. Ask ākonga to draw a picture of one of these objects. Attach them to a chart of 'Pushing and Pulling'.

Session 3: Popcorn containers

In this activity we make popcorn containers for the Three Bears. Any other picture book that describes a quantity of something (e.g. an amount of food) could be used in this session. 

  1. Read or tell the story "Goldilocks and Three Bears" to ākonga. When you have finished, tell ākonga that the bears are going to the movies and want to buy some popcorn.
    What size popcorn would Father Bear want?
    What size popcorn would Mother Bear want?
    What size popcorn would Baby Bear want?
  2. Tell ākonga that they are going to make popcorn containers for the bears' popcorn. Show ākonga how to make popcorn cones by rolling a piece of paper or light card. Ākonga could decorate the paper before rolling it up to make a container.
  3. Ask ākonga to make containers for the three bears' popcorn.
  4. As a class, look at the popcorn cones made.
    How could we check if Father Bear's cone holds the most?
  5. Give ākonga popcorn to pour between the containers to check.

Session 4: Fill it up

In this activity we pour water (or beans) between containers and guess how high up the water or beans will go.

  1. Show the class a cup full of beans or water and an empty ice-cream container.
    What do you think will happen if I pour the beans into the ice-cream container?
    How far will it fill up?
  2. Check and discuss.
    Did you guess correctly?
    Is the container full?
    Is it empty?
  3. Give each ākonga a cup full of beans. Put several containers of varying sizes around the room. Ask the ākonga to pour their beans into the containers, first guessing how high up they think the beans will go. Alternatively this station could be set up outside on a water tray with various containers for ākonga to guess and fill. 

Session 5: Book corner

In this activity we look at some picture books that could be read to ākonga or enjoyed independently by ākonga, to reinforce measuring language associated with volume and mass.

  1. Who Sank the Boat? Pamela Allen. (1996). This is also available in te reo Māori - Nā Wai Te Waka I Totohu?
  2. Goldilocks and the Three Bears
  3. Mr Archimedes' Bath.  Allen, P. (2020).
  4. Watch Out! Big Bros Coming! Alborough, J. (1997).
  5. The Bad Tempered Ladybird. Carl, Eric. (1977).

More titles and measurement specific activities are available on the Level 1 Measurement Picture Books page.

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Level One