Grade 2: Measuring in Centimetres

Measuring in Centimetres

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Content

Expectations:

E2.2 explain the relationship between centimetres and metres as units of length, and use benchmarks for these units to estimate lengths

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

Measurement Principles

Sometimes you measure directly; sometimes you use indirect means.
Familiarity with certain measurements referents help you estimate.
In order to measure, a series of uniform units must be used or a single unit must be used repeatedly.
The unit chosen for a measurement affects the numerical value of the measurement; a bigger unit results in a smaller number of units. This is why a measurement without a unit is meaningless.

Learning Goal

We want students to

Understand/explain what a centimetre is (benchmark centimetre cube)
Understand/explain how to use a ruler to measure centimetres and metres
Know when to measure with centimetres and metres
Understand how to not measure from zero

Success Criteria

I can demonstrate how to measure with a centimetre ruler (from zero and not from zero)
I can estimate centimetres using non-standard units of measure

materials Math Language/Vocabulary

Centimetre cubes Centimetre
Primary rulers (centimeters only if possible)

Minds On

Source: Barrett, J., Cullen, C., Behnke, D., & Klanderman, D. (2017) A Pleasure to Measure” Tasks for teaching measurement in the elementary grades. Lesson: “Which is the shortest of all your toes?” (pg. 13)

Read the poem:

Which is Longer?

Which is longer,

A car or a block?

Which is longer,

A shoe or a sock?

Which is shorter,

A tree or a flower?

Which is shorter,

A minute or an hour?

Which is longer,

A bike or a frog?

Which is longer,

An ant or a dog?

Which is the shortest,

Of all your toes?

And who has the very

Shortest nose?

-Anonymous

Read the poem again and have students answer each question posed by it. Ask how they can tell which is longer or shorter.

Can students substitute other objects to compare in the poem? For example, they might replace “a tree or a flower” with a “bush or a dandelion”. Encourage them to stay in the same category of objects for each pairing, but do not stress the need for words to rhyme.

Teacher Notes:

Are students thinking and talking about length, or are they merely considering overall size?

Action!

Source: Barrett, J., Cullen, C., Behnke, D., & Klanderman, D. (2017) A Pleasure to Measure” Tasks for teaching measurement in the elementary grades.”Lesson: Activity 8: On the Other Hand…” Pg. 20-21

- Before we start: (Distance learning) Clear off the kitchen table. (At School) Clear off one table.

Show the drawing and explain how people have used the human hand as a measurement for horses. For this purpose, a hand is the standard unit of measurement of equine height and is equivalent to 4 inches (approximately 10 cm). A horse/pony is measured from the ground to the top of the shoulder. Ponies for example measure about 14.2 hands or 142 cm or 1.42 m.

Ask the students to measure the length of a table by using their hands and then measure the table’s height and width in the same way.

Record their findings about the length of a table in hands, and list the numbers on a poster without ordering them or graphing them at first.

Consolidation Ideas

Review the Poster and ask: “What do these numbers tell us about the table’s length?” Help students notice the range and frequency of some of the numbers.

Expect

Students will probably not get the same result. If they do not, can they explain why not? Do the differences mean that some did the activity correctly and others did not? Have several students demonstrate how they used their hands. Point out that using different features of their hands(palm width versus wrist-to-fingertip length) will produce different measures of the same object.
Are students consistent in using the same hand lengths, hand widths or hand spans when they measure? Are their fingers spread apart each time or kept together when using hand widths? Do they measure without overlaps or gaps?

Independent Task / Assessment Opportunities

Independent Task / Assessment Opportunities:

(Face to Face classroom) Repeat measuring the height and width of the desk using centimeter cubes. And then have them line up the centimetre ruler from the zero to measure in centimeters.

(Distance Learning) Using Explain Everything (You need to be on the iPad and to open the file it will initially say unsupported. Press the three dots at the top right and choose Explain Everything)to have students measure the desk using centimeter cubes in this project.

Student Self Assessment: (French and English)

Teacher Rubric: https://docs.google.com/document/d/1C28aCyHpZFAwz6C7AGxu_hAvPTSUKbHtNvH3R-d9yDM/edit?usp=sharing

Technology

Explain Everything

N.B: You need to be on the iPad and to open the Explain Everything file. It will initially say unsupported. Press the three dots at the top right and choose Explain Everything.