Exploring Length

Lesson Overview

Duration: 40 minutes
Class Size: 19 students
Age Group: 7 years old (1st Class)
Curriculum: Curriculum Framework for Ireland (IE) - Mathematics
Theme: Length
Strand: Measures
Strand Unit: Length
Relevant Learning Outcomes:

• Measures: "Explore, compare and order lengths using non-standard and standard units."
• Use language related to length including longer, shorter, taller, smaller, and measurements in centimetres and metres.
• Develop estimation skills related to length.

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Learning Intentions and Success Criteria

WALT (We Are Learning To):

• Understand the concept of length and learn to measure using standard (centimetres) and non-standard units.
• Compare and order objects by length using accurate measurements.

WILF (What I am Looking For):

• Can identify longer, shorter, taller objects.
• Can estimate and measure the length of objects using centimetres (rulers) and non-standard units (hands, paper clips).
• Can explain reasoning when comparing lengths.
• Can work collaboratively in pairs to measure and record data accurately.

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Resources Needed

• A variety of classroom objects (pencils, books, rulers, erasers)
• Measuring tapes or rulers marked in centimetres
• Sets of identical objects (paper clips, cubes) for non-standard measurement
• Whiteboard and markers
• Worksheets with length comparison and measuring activities
• Large A3 paper for group recording
• Visual stimulus slide/image showing objects of different lengths (e.g., a giraffe vs a rabbit, pencil vs crayon)

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Lesson Structure

1. Introduction & Stimulus (5 minutes)

• Show a vivid image of different animals/objects with varying lengths (e.g., a giraffe, a rabbit, a pencil, and a crayon).
• Ask students, “Which is longer? Which is shorter? How do you know?”
• Highlight that today they will explore how to measure and compare these differences in length.
• Engage the class in a very quick oral brainstorm using higher-order questions like:
  • “Why do you think measuring length is important in everyday life?”
  • “Can an object be long but not tall? What might that mean?”

2. I DO (Teacher Modelling) (8 minutes)

• Model how to measure the length of a pencil using a ruler.
• Emphasise correct ruler use: placing at zero, reading centimetres carefully, noticing half centimetres and whole centimetres.
• Show non-standard measurement: measuring the same pencil with paper clips lined up.
• Demonstrate comparing lengths by placing two objects side by side.
• Use think-aloud: “I can see this pencil is longer than my eraser because the number on the ruler is higher.”
• Ask a lower-order question: “What number does the pencil end on?”
• Higher-order question: “If we use paper clips instead of a ruler, what might be some challenges?”

3. WE DO (Guided Class Activity) (10 minutes)

• Display 3 different objects on a table.
• Together as a class, measure each object using rulers and non-standard units (e.g., hands or paper clips).
• Ask students to discuss and decide which object is longest and which is shortest, and explain why.
• Record results on a chart visible to all students (e.g., Object - Length in cm - Length in paper clips).
• Questions to prompt thinking:
  • “Does measuring with paper clips give the same result as the ruler?”
  • “How can we be sure we place the ruler correctly?”
  • “Why might we choose one measuring tool over another?”

4. YOU DO (Independent or Pair Work) (15 minutes)

• Distribute objects and measuring tools to pairs. Each pair receives a worksheet with measuring tasks:

  1. Estimate the length of your object before measuring. Write down your estimate.
  2. Measure the object in centimetres using a ruler.
  3. Measure the same object using non-standard units from the kit.
  4. Draw a picture of your object and label its length.
  5. Compare your results with your partner and write one thing you learned about measuring length.

• Circulate and support with prompts and questioning:

  • Lower-order: “What number did you get when you measured?”
  • Higher-order: “How close was your estimate to your actual measurement? Why do you think that is?”
  • “Did both measuring methods give the same results? Why might differences occur?”

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Plenary (2 minutes)

• Gather class attention to recap:
  • Ask volunteers to explain how they measured an object.
  • Using an exit question, “Why do we need to measure length carefully?” or “What did you find tricky when measuring with paper clips?”
• Reinforce learning by highlighting good examples of description and measurement shared during the lesson.

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Assessment for Learning (AfL)

• Ongoing formative assessment during We Do and You Do stages, ensuring students' understanding of length comparison and measuring accuracy.
• Check worksheets for correct measurement, estimation skills, and reflective comments.
• Use oral questioning and observation to verify comprehension and reasoning skills.

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Differentiation and Inclusion

• Provide rulers with larger numbers or colour-coded units for students who need visual support.
• Pair lower-ability students with peers who can model measuring skills.
• Offer objects of varying complexity to measure, adapting the challenge based on the student’s ability level.
• For extension, challenge advanced students to order multiple objects by length or convert between centimetres and standard non-standard units used.

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Connection to Curriculum Framework for Ireland (IE)

This lesson directly supports the early stage of the strand “Measures,” focusing on length and incorporates key components:

• Recognition and use of vocabulary associated with length.
• Measuring using standard units (centimetres) and non-standard units in order to develop understanding of measurement concepts.
• Encouraging estimation skills enhances mathematical reasoning and numerical sense, aligned with Curriculum standards for 1st class.
• The focus on practical, hands-on measurement activities supports the Curriculum’s emphasis on active learning and developing concrete understanding before moving to abstract concepts.

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End of Lesson Plan