Physical Science / Unit 1: Science Skills and Measurement
1.2 SI Units and Measurement
Notes
Scientists use the International System of Units (SI) so everyone measures the same way.
- Length: meter (m). Mass: kilogram (kg). Time: second (s). Temperature: kelvin (K).
- Volume of a liquid is often measured in liters (L) or milliliters (mL) with a graduated cylinder. Volume of a solid in $\text{cm}^3$ or $\text{m}^3$.
- Common tools: meterstick (length), balance (mass), stopwatch (time), thermometer (temperature).
- Mass is the amount of matter in an object. Weight is the force of gravity on that mass.
- Read a graduated cylinder at the bottom of the curved surface (the meniscus), with your eye level with it.
Practice
What is the SI base unit of mass?
The kilogram is the SI base unit of mass; the gram is a smaller metric unit.
Which tool should you use to find the mass of a rock?
A balance measures mass.
A rectangular block measures 4 cm by 3 cm by 2 cm. What is its volume?
Volume = length times width times height: $4 \times 3 \times 2 = 24$.
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