E2.5 Use various units of different sizes to measure the same attribute of a given item, and demonstrate that even though using different-sized units produces a different count, the size of the attribute remains the same.

Activity 1: Use Different Sized Units to Measure Capacity


Here are two boxes.

A box "A" that is wide, but not very thick. A Box "B" is a  a cube. Equal  width and height.

Ask students to check the capacity of each of the boxes using the two paper cups filled with rice as a unit of measurement.

Ask the following questions.

  • What do you notice?
  • Does the capacity of the two boxes change when a different non-standard unit of measurement is used to measure it?
One large paper cup and one small paper cup.

Source: adapted and translated from En avant, les maths! 3e année, CM, Sens de l'espace, p. 3-4.

Extension

Have students repeat the activity by measuring another measurable attribute such as the height or area of a surface of each box.

Activity 2: Demonstrate That the Size of an Attribute Remains Unchanged


Present students with the following situation.

Marko measured the length of a table and a book, and this is what he found.

The Length

Objects

Non-Standard Units 

Counters

Cubes

Paper Clips

Table

41

34

about 20

Book

about 16

13

about 7

He also measured the mass and the area of two other objects.

The Mass Measured With a Pan Balance Scale

Objects

Non-Standard Units

Cubes

Counters

Cork Stoppers

Pencil sharpener

about 21

43

31

Eraser

about 19

39

about 28

The Area 

Objects

Non-Standard Units

Sticky Notes

Cubes

Pattern Blocks

Desk

about 64

186

165

Book

about 9

32

28

Ask the following questions.

  • What do you notice?
  • Does the size of the attributes (length, mass, and area) change when different non-standard units are used to measure it? Why?

Ask students to compare the number of units counted for each of the objects. Establish relationships between the number of units required to determine the measurement of an attribute and the length, area, or mass of the non-standard unit of measurement used.