Lesson · S.4.1
Scientific measurement and tools
SI units and metric prefixes, which tool measures volume, mass, or length, and why precision and accuracy are not the same thing.
ObjectiveS.4.1Read2 minExam weightScientific Reasoning ≈ 21% of Science
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- Convert between metric prefixes such as kilo, centi, and milli without a calculator.
- Match the correct measuring tool, a ruler, balance, or volumetric glassware, to what is being measured.
- Distinguish a precise measurement from an accurate one.
What the lesson concludes
- SI prefixes scale consistently: kilo multiplies by 1,000, centi divides by 100, milli divides by 1,000.
- Match the scale of the unit to the size of the object: kilometers for distance between towns, millimeters for an insect.
- Rulers measure length, balances measure mass, and volumetric flasks or pipettes beat a graduated cylinder for accuracy.
- Read a meniscus at eye level, at its centre, not at its upper or lower edge.
- Precision is repeatability; accuracy is closeness to the true value. A result can have one without the other.