1. Units of Measure
Section 1.2 Metric Length

2. Pre-View 1.2 Meter – the standard SI unit for measuring length.
Ruler or meter stick – tool used to measure length in centimeters or millimeters

3. The smallest marks on a ruler or meter stick indicate millimeters (mm).
There are 1000 mm in one meter.
The longer marks on a ruler or meter stick show centimeters (cm) – 10 mm = 1 cm, and there are 100 cm in one meter.
Longer lengths are measured in kilometers (km), which are 1000 meters.

5. 10 mm or
1 cm

6. SI unit of Length: Kilometer (km)
When to use it…
Use kilometers for long distances.
Example:
The distance from Birmingham to Anniston is about 106 km

7. SI unit of Length: Meter (m)
When to use it…
Use meters instead of feet or yards.
Example:
The height of an average room from floor to ceiling is about 3 m

8. SI unit of Length: Centimeter (cm)
When to use it…
Use centimeters instead of inches.
Example:
One inch is 2.54 cm. The width of notebook paper is about 21.6 cm

9. SI unit of Length: Millimeter (mm)
When to use it…
Use millimeters for small but visible lengths.
Example:
The diameter of an average pencil is mm

10. SI unit of Length: Micrometer (μm)
When to use it…
Use micrometers to measure very small or microscopic dimensions.
Example:
The length of a paramecium is about 50 μm