E2.3 Measure and draw lengths in centimetres and metres, using a measuring tool, and recognize the impact of starting at points other than zero.
Activity 1: Making a Measuring Instrument
A large number of measuring tools (for example, a ruler) have been designed to determine the measurement of various attributes based on standard units of measurement. Even if this strategy makes it possible to obtain a measurement quickly, it nevertheless requires, on the part of the person who uses it, a good sense of measurement and a good ability for abstraction. To help students understand the importance of these tools and how to use them correctly, the teacher can suggest that they make one. For example, build a measuring tape with 100 one-centimetre interlocking cubes. Ask students to compare their tool with a tape measure. Have them use their measuring tool to measure various lengths, then measure the same lengths using a flexible plastic or flexible metal tape measure, or a trundle wheel. Ask the students to compare their results and their observations on the use of each of these tools.
Source: translated from Guide d’enseignement efficace des mathématiques, de la maternelle à la 3e année, Mesure, p. 92.
Activity 2: Measuring Length with Standard Units - Traditional Ruler
Goal
In this activity, students use of a 30 cm ruler as a measuring tool.
Material
- 30 cm ruler per student (with 1 cm intervals between each line up to 30 cm)
- 30 cm ruler for the teacher
Present the traditional ruler (with intervals of 1 cm between each line up to 30 cm).
Give each student a ruler.
Ask the following questions:
- How does this ruler differ from the one constructed in the “Making a Measuring Instrument” activity? (There are lines and numbers on the ruler.)
- How does this ruler differ from the metre? (It is much shorter and easier to handle)
- What unit is represented by the space between two large lines? (The space between two large lines represents 1 cm.)
- What does the number under a line mean? (The number under a line represents the amount of centimetres from the first large line on the left of the ruler)
- How many centimetres is the last large line on the right side of the ruler? (It is 30 cm)
- What unit is represented by the space between two small lines? (The space between two small lines represents 1 mm.)
Source: translated from L'@telier - Ressources pédagogiques en ligne (atelier.on.ca).
Activity 3: Measuring Length with Standard Units - the Metre
Goal
In this activity, students determine the length of various objects using a “broken ruler”.
Material
- one metre stick per student
- one metre stick for the teacher
Present students with a tape measure (rigid if possible).
Ask the following questions:
- What unit does the space between two large lines represent? (The space between two large lines represents 1 cm.)
- What does the number under a line mean? (The number under a line represents the amount of centimetres from the left end of the metre.)
- How many centimetres does the right end of the metre represent? (The right end of the metre represents 100 cm.)
- What does the space between the smaller lines represent? (The space between two smaller lines represents 1 mm.)
- Are there any other units of the metre that are not shown? Which ones? (On some metres, the decimetres [dm] are indicated.)
Source: translated from L'@telier - Ressources pédagogiques en ligne (atelier.on.ca).
Activity 4: Measuring Length with Standard Units - Piece of Ruler
Goal
This activity facilitates the understanding that measuring with a ruler is counting a number of spaces, not reading a number under a line.
Note: Using a ruler that does not have the first units helps the student understand that measuring with a broken ruler is equivalent to finding the amount of units, not reading a number under a line.
Material
Cardboard strips 40 cm long and 3 cm wide.
Instructions
- Using a strip of cardboard, create a broken ruler similar to the illustration below, with approximately 25 strokes (25 centimetres from 21 cm to 46 cm).
- Invite students to use the constructed ruler to determine the length of various common objects and complete the following table.
Name of the Object
What is Measured: Length, Width, Height, Distance
From ... to ...
Quantity of Units
My red pencil Length 21 to 25 4
Source: translated from L'@telier - Ressources pédagogiques en ligne (atelier.on.ca).
Activity 5: Measuring Length with Standard Units - Other Measuring Tools
Goal
In this activity, students use a variety of tools to measure the side lengths of different two-dimensional shapes found in the classroom or drawn by students.
Material
- tape measure
- trundle wheel
- ultrasonic distance estimator
- straws
- wooden sticks
- coffee sticks
- toothpicks
- paper clips
- dominoes
Make a list of two-dimensional shapes that are present in the classroom or that students can construct (for example, a domino, the door, the width of a desk, pattern blocks, two-dimensional shape constructed with straws).
Ask students to estimate the length of the sides of the objects on the list.
Ask them to measure the sides of the objects using the measuring tools provided.
Encourage students to express lengths with different units (for example, the shelf is 120 cm or 1 m and 20 cm).
Source: translated from L'@telier - Ressources pédagogiques en ligne (atelier.on.ca).