T1-L09: Measurement & Estimation

Name:

Class:

Date:

Folio: pp. 32–39

Outcomes: TE4-PPM-01 TE4-MSC-01 Folio pp. 32–39

Learning Intention

We are learning to measure accurately using millimetres and to estimate lengths before measuring.

Success Criteria

I can read a ruler to the nearest millimetre
I can measure objects accurately
I can estimate lengths before measuring
I can explain why measurement is important in engineering

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Do Now

Estimate the length of your pencil in millimetres. Write it down — no rulers yet!

Your estimate (mm)	Actual measurement (mm)	Difference

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Key Vocabulary

Standard: Fill in the definition. | Support: Definitions shown in grey — read and copy into your folio. | Extension: Use each term in a sentence.

Term	Definition	Use in a sentence (Extension)
Millimetre (mm)	One thousandth of a metre; the smallest unit on a standard ruler
Centimetre (cm)	One hundredth of a metre; equals 10 mm
Metre (m)	The base unit of length in the metric system; equals 100 cm
Estimation	An educated guess of a measurement before using a tool
Accuracy	How close a measurement is to the true (actual) value
Precision	How consistent repeated measurements are (close to each other)
Ruler	A measuring tool with marked units (mm and cm) used to find length
Measurement	The process of finding the size, length or amount of something using a tool

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How to Read a Ruler — 4 Steps

Step	Rule	Why it matters
1	Start at 0, not the edge
2	Read at eye level (look straight down)
3	Count spaces between marks, not lines
4	Record to the nearest mm

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Body Measurement References

Measure each body part and record YOUR personal references. These help you estimate!

Body part	Standard reference	Your measurement (mm)
Fingernail width	≈ 10 mm (1 cm)	mm
Hand span (thumb to pinky, spread)	≈ 200 mm (20 cm)	mm
Forearm (elbow to fingertip)	≈ 500 mm (50 cm)	mm
One big stride (step length)	≈ 1,000 mm (1 m)	mm

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Estimate & Measure Classroom Objects (Folio pp. 38–39)

Estimate FIRST (no rulers!), then measure. Use your body references to help estimate.

Object	Estimate (mm)	Actual (mm)	Difference (mm)

Which object was your closest estimate? Which was furthest? Why?

🔵 Support — Measurement Checklist

Before EVERY measurement, check these steps:

Find the 0 mark on your ruler (not the edge!)
Place the 0 at one end of the object
Look straight down (no angle!)
Count the spaces (not lines) past the last cm mark
Write your answer in mm

Conversion Reminder

1 cm = 10 mm1 m = 100 cm1 m = 1,000 mm

🟠 Extension — Measurement Mastery

Convert ALL your measurements between mm, cm, and m.

Object	mm	cm	m

Challenge: Calculate the percentage error of each estimate:

% Error = (|Estimate − Actual| ÷ Actual) × 100

Research: What tools do engineers use for measurements smaller than 1 mm?

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Exit Ticket — Reflection

1. Which classroom object was HARDEST to estimate accurately? Why?

2. What is one thing you will do differently next time you measure?

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Self-Assessment

Success Criteria	Got it 🟢	Nearly there 🟠	Need help 🔴
I can read a ruler to the nearest millimetre	●	●	●
I can measure objects accurately	●	●	●
I can estimate lengths before measuring	●	●	●
I can explain why measurement is important in engineering	●	●	●