E2.4 Use units of time, including seconds, minutes, hours, and non-standard units, to describe the duration of various events.
Skill: Describing Time Using Seconds, Minutes, Hours, and Non-standard Units
The concepts of measuring time and time benchmarks are very abstract for young children.
In the primary grades, students learn to estimate and measure the length of different periods of time, and to establish relationships between different periods of time. It is therefore important to address these concepts through learning situations in authentic contexts.
The concept of duration is difficult for students to grasp because of the emotional component they associate with it. This concept can only be developed through activities related to their experiences. At the beginning of the primary grades, students have difficulty realizing that a minute is always the same length of time. For example, a 15-minute recess seems shorter to them than a class session of the same length. Students could measure a duration in terms of a period of time that they are familiar with; for example, students often associate a period of time with the number of sleeps that it takes: “There are four sleeps left before we leave.”
Source: translated from Guide d’enseignement efficace des mathématiques, de la maternelle à la 3e année, Mesure, p. 66.
The passage of time is measured by counting units of time that repeat in a regular and predictable manner: the beats of a metronome; the dripping of a faucet; the natural cycles of a day; the swing of a pendulum; the seconds, minutes, and hours of a clock.
Similar to measuring physical length, a length of time can be measured using different units of different sizes. The smaller the unit of time used, the more precise the measurement. Similar to all continuous attributes, the measurement of time is always approximate.
Around the world, standard units of time – seconds, minutes, hours – are used to communicate the length of time of an event. Measuring tools, such as stopwatches, keep track of the unit count.
Source: The Ontario Curriculum, Mathematics, Grades 1-8, Ontario Ministry of Education, 2020.
Steps in the Act of Measuring
The act of measuring involves a series of reflections, decisions, and actions that lead to obtaining and communicating an accurate and contextually appropriate measurement. This involves a number of steps that are the same for all the attributes studied in the primary grades: length, area, capacity, mass, and time. Although the number and identification of these steps vary somewhat among researchers, they can generally be articulated sequentially as follows:
- determine the attribute to be measured;
- choose the unit;
- determine the measurement;
- communicate the result.
Source: translated from Guide d’enseignement efficace des mathématiques, de la 4e à la 6e année, Mesure, p. 83.
Example of the steps of the act of measuring time
|
Steps |
Questioning |
|---|---|
|
Determine the attribute to be measured |
“Jacob reads quickly. He can read two pages in his book in one minute. If the book has 20 pages, can he read it in five minutes?” (He determines the length of time it takes to read 20 pages.) |
|
Choose the unit of measurement |
“What units does he use?” (He uses minutes.) |
|
Determine the measurement |
“What will his approach be?” (He uses a 5-minute timer. He synchronizes the start of reading page 1 with the start of the timer. When the timer goes off, he notes which page of the book he is reading.) |
|
Communicate the result |
“How do we communicate the outcome?” (Jacob has read 11 pages in 5 minutes so he can't read the whole 20 page book in 5 minutes.) |
Source: translated from Fiche de la maternelle à la 3e année Attribut temps, p. 3.
Skill: Use Units of Time
In the primary grades, it is important that students learn to use some of the common measuring tools, taking into account the degree of precision required and the importance of accuracy of measurement.
To measure time, students can use non-standard units such as hand or foot claps or standard units, such as seconds, minutes, and hours using tools such as a stopwatch.
Source: translated from Guide d’enseignement efficace des mathématiques, de la maternelle à la 3e année, Mesure, p. 93.
Knowledge: Time
Time is an attribute that can be used to designate two different characteristics of a situation or an event: a precise moment or a duration.
Time as a precise instant refers to the time it is when an event takes place. It is an attribute that can be read, for example, on a watch or a clock (Grade 3).
Time as duration refers to the interval of time that elapses between two moments of an event, such as the beginning and end. It is an attribute that can be measured, for example, with a stopwatch.
Inverse Relationship
The smaller (or larger) the unit of time used, the greater (or smaller) the number of units required to determine the duration.
Relationship between conventional units of measurement
- seconds and minutes
- minutes and hour
Source: translated from Fiche de la maternelle à la 3e année Attribut temps, p. 2-3.