"Heaviest Pencil Case"

Let's investigate - Who has the Heaviest Pencil Case?

This inquiry based activity continues on from the emerging learning stage. Students are now not just comparing, they are working with informal units to quantify mass. This open task demonstrates how engaging learning to measure mass with informal units can be. In small groups, Children will practice measuring with informal units (cubes) to find out how many cubes each pencil case weighs using a balance scale.  

Most children have a pencil case, and children are very familiar with them using them every day. By posing a challenge to learn who has the heaviest pencil case, the students are interested and curious to investigate. This hands-on activity challenges the children’s mathematical thinking and improves their reasoning and key understanding around measuring and quantifying mass.

• Activity inspired by article - Beach Towels and Pencil Cases: Interesting, Inquiry-based Mathematical Investigations (Attard, 2017).

Materials

• Balance scales one for each group

• Tub of unifix cubes one for each group

• A pencil case for each child

• Paper and pens to record findings and Post it notes& marker for each group 

Activity

(1) In groups of 4-5, children will first be asked to estimate the mass of their pencil cases by holding and comparing them.  What do you think? How many cubes will it take to balance your pencil case? Building on this knowledge they now have the opportunity to test these estimations.

(2) Children will use the balance scale to learn how many cubes are needed to balance the scale.  The number of cubes needed to balance each pencil case will be recorded next to their names and estimation. Once completed, groups can write the mass of each pencil case clearly on a post it note and placed on the pencil case.  Groups will then be invited to the front of the classroom to order their pencil cases from heaviest to lightest.

(3)  Once all groups have done this, as a class we will sort the pencil cases in order of mass from lightest (smallest number of cubes) to the heaviest (largest number of cubes).The heaviest and the lightest pencil case will be announced. Group discussion.

Questions to ask:

-        How close were you to your estimation?  Did you need many more cubes or less?

-        Who had the heaviest pencil case in the group?

-        Who had the lightest pencil case in the group?

-        “Bigger is heavier” discuss and consider the truth to this statement relating to the size of the pencil cases, and their mass.  Does a larger size mean less mass – less cubes?

Enabling prompts

-       Ensure there is a simple visual cue available for students to assist them. Eg;  Clear diagrams of a balance scale when balanced and   when an item is heavier and lighter with a set of simple instructions.

-       Children needing more support can be given cubes of the same colour. Working with just the one colour may keep them focussed and    assist them to count correctly.

-       Groups with Children who may need a little more assistance, can be given extra time to weigh their case and record their findings.

Extension

-        Children can be challenged with additional questions to answer, eg; How many more cubes did the heaviest pencil case have than the lightest?

-       Were there any pencil cases close in mass – how many cubes?

-       Mystery challenge - Calculate the teacher's pencil case mass and place it with the class pencil cases in its correct position according to its mass.