Measure with Informal Units

Overview

Today you will measure everyday objects using informal units (like hands, paper clips, or blocks) and compare which unit gives a shorter or longer measurement.

Learning intentions

WALT: We are learning to measure length using different informal units.

• Students will choose an informal unit and use it to measure an object.
• Students will record measurements with a clear mark system.
• Students will compare measurements made with different informal units.

Success criteria

• I can measure a line-length object using one informal unit correctly.
• I can record my measurement (for example, by counting marks or writing the number with a unit).
• I can explain why different measurements happen when different units are used.

Curriculum links

• Measure and estimate lengths using informal units for familiar objects.
• Use simple measurement strategies (such as lining up units with no gaps or overlaps).
• Describe and compare measurements made using different units.

Lesson structure (30 minutes)

1. 3 minutes – Hook (object demo)

• Teacher displays two strips of paper (or a ruler-like card) and asks: “How can we tell which is longer without a ruler?”
• Students discuss quick ideas (hands, blocks, paper clips). Teacher confirms we will use informal units.

2. 7 minutes – Mini-teach: measuring like a scientist

• Teacher models measuring a short object with one informal unit (e.g., a linking cube).
• Key instructions: start at one end, place units end-to-end (no gaps/overlaps), count carefully, and record.
• Students practise as a class on a large “measurement mat” with visible end points.

3. 10 minutes – Hands-on stations: measure and record

• In groups of 2–3, students rotate through 2 quick stations (teacher chooses, or set up in corners).
• Station A: Measure a “string of objects” (e.g., pencils, erasers, craft sticks) using a provided unit (hand, paper clip, cube).
• Station B: Measure a longer strip using longer informal units (blocks) and/or shorter units (paper clips) to compare.
• Students record: a number and the unit they used (e.g., “7 cubes” or “10 paper clips”), using sentence starters if needed.

4. 5 minutes – Compare and explain (whole class share)

• Teacher brings out one object measured by two different groups (short unit vs long unit).
• Prompt: “Why did one group get a bigger number? Which unit was smaller?”
• Students use stems: “We got ___ because we used ___.”

5. 5 minutes – Quick check (exit ticket)

• Each student measures one item on an individual mat using a chosen informal unit and records the result.
• Exit ticket question: “My unit was (hand/cubes/paper clips). My measurement was ___.”

Resources

• Object set: pencils/erasers/craft sticks or measuring strips (2–3 sets)
• Informal units (pre-sorted):
• linking cubes, paper clips, small craft sticks
• optional “hand measure” cards (with teacher guidance)
• Measurement mats with clear starting and stopping ends
• Recording sheets with number line/boxes for counting marks
• Sentence starters (e.g., “I used ___ to measure.” “My object is ___ ___ long.”)
• Coloured pencils/markers for recording
• Group labels and timer for station rotation
• Visual cue chart: start-end, no gaps, count, record

Assessment

• Teacher observation checklist during stations:
• correct end-to-end placement
• accurate counting and recording
• Exit ticket review for:
• number recorded matches the student’s counting
• students identify the unit used
• Listening during the compare discussion to confirm understanding of why measurements differ.

Differentiation

• Support (for EALD and neurodivergent students)
• Provide a measuring mat with highlighted start/end points.
• Pre-allocate a unit per student for the first station (reduce decision overload).
• Use visual steps: start, line up, count, write.
• Offer sentence starters and allow pointing/counting marks instead of full sentences.
• Provide extra adult/group support at the first station until students demonstrate end-to-end placement.
• Targeted scaffolds
• Give a “no gaps” reminder card next to the unit container.
• Use one object for whole-class modelling, then only introduce one new object at a time.
• Extension (advanced learners)
• Challenge: measure the same object using two different informal units and then write both measurements and a comparison statement (e.g., “When we used smaller units we got a larger number.”).
• Additional challenge tied to the lesson description: choose a rectangular classroom object (e.g., book cover) and find its area using proper dimensions by measuring length and width with a ruler or standard units if available, then calculate area (length × width).
• EALD considerations
• Focus on key language: longer/shorter, more/fewer, smaller/bigger units, end-to-end, count, measure.
• Allow students to demonstrate understanding with gestures or diagrams if writing is limited.

Extension (optional)

• If time allows: “Unit swap” game—groups swap the measuring unit and predict whether the number will get bigger or smaller before re-measuring.