LESSON PLAN

Linear Measurement: Centimetres and Metres

Apothem Team

Grade 2 · Measurement

LESSON AT A GLANCE

Warm-up

5 min

Explore

15 min

Consolidate

10 min

Practice

12 min

Exit ticket

3 min

Warm-up

How wide is your hand? How tall is your chair? Estimate first using personal referents, then measure to check. Track estimates vs. measurements. Whose estimate was closest? What referent did they use?

Explore

Measurement hunt: students measure 8 objects around the classroom, first estimating (using personal referents) then measuring. Record: estimate, actual measurement, difference. Identify the largest estimation error and discuss what referent would have helped.

Consolidate

Practice

Students measure 6 objects (3 in cm, 3 in m), recording estimates and measurements for each. Exit ticket: estimate the length of the classroom in metres. Write your personal referent and your estimate.

Exit ticket

TIP Always estimate before measuring. If a student skips estimation, ask: before you check, what do you think it will be? This builds the habit of having a predicted value, which is how all good measurements are made.

WORKED EXAMPLES

A student measures a book as 30 cm but the book is clearly about 20 cm long. What likely went wrong?

The most common error: starting from 1 on the ruler instead of 0. If the student started at 1, every measurement is 1 cm too large. Alternatively, the ruler was not straight. Check both. Ask: where did you put the start of the ruler?

What personal referent would you use to estimate 50 cm?

Half a metre: roughly from fingertips to elbow, or from a shoulder to an outstretched hand. Any known 50-cm reference works. The goal is having a mental image of 50 cm to compare against.

MATERIALS

•Rulers (cm) and metre sticks

•Objects of various lengths to measure

•Personal referent cards (fingernail, hand span, arm span)

•Estimation recording sheets

•Measuring tape

WATCH FOR

!Starting at 1 instead of 0 on the ruler is the most common measurement error in Grade 2. Explicitly show both the correct and incorrect starting positions.

!Students may confuse cm and m, estimating a classmate's height as 130 cm vs 130 m. Regular exposure to measured objects builds intuition for appropriate magnitudes.