BIOL 1406

PreLab 1.3

What are the SI units for measuring distance?

15 cm ruler


In lab, you will generally use a 15 cm ruler to measure distance.  The numbers on the metric scale of the ruler represent centimeters, and the smallest calibration marks represent millimeters.

The basic unit of distance is the meter (m). You should be able to rapidly convert measurements between meters, centimeters, millimeters, and micrometers.

One meter (m) = 100 centimeters (cm) = 1,000 millimeters (mm) = 1,000,000 micrometers (μm)
One centimeter (cm) = 10 millimeters (mm) = 0.01 meter (m)
 		 = 10,000 micrometers (μm)

GENERAL RULES FOR CONVERTING SI UNITS
1. If the units get smaller (e.g. meters to centimeters) then the number must get larger, meaning you must multiply (in this case by 100) or move the decimal point to the right (in this case by 2 places).

 
2.

If the units get larger (e.g. millimeters to centimeters) then the number must get smaller, meaning you must divide (in this case by 10) or move the decimal point to the left (in this case by 1 place).

 

For example:

To convert meters to centimeters, multiply by 100.

3 m x 100 cm/m = 300 cm

To convert centimeters to meters, divide by 100:

650 cm / 100 cm/m  = 6.50 m

To convert centimeters to millimeters, multiply by 10.

12 cm x 10 mm/cm = 120 mm

To convert millimeters to centimeters, divide by 10:

170 mm / 10 mm/cm = 17 cm

Your Turn
Express the following measurements in meters:
340 cm = Hint Check your answer.
23 cm = Hint Check your answer.
4,250 mm = Hint Check your answer.
Express the following measurements in centimeters:
8.54 m = Hint Check your answer.
0.0006 m = Hint Check your answer.
390 mm = Hint Check your answer.
Express the following measurements in millimeters:
0.0007 m = Hint Check your answer.
0.24 m = Hint Check your answer.
0.62 cm = Hint Check your answer.

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