http://www.ck12.org Chapter 1. What Is Science?
1.3 Unit Conversions
Objectives
- Perform unit conversions.
- Properly use scientific notation.
Vocabulary
- conversion factor:A mathematical expression equating two different units, such as 1 m = 100 cm.
- scientific notation:A number expressed in scientific notation is written as a number between 1 and 10
multiplied by a power of ten.
Introduction
Just as there are many spoken languages, there are many ways of expressing the same quantities in science. All
scientists throughout the world measure length using centimeters, meters, and kilometers rather than inches, feet,
and miles. Even within this single system of measurement, it is still necessary to reinterpret, or convert, quantities.
For example, it is more efficient to express 1,000 meters as 1 kilometer, or to express 150 centimeters as 1.5 meters
(Table1.1).
TABLE1.1: A Few Select Unit Equivalencies
Unit Equivalent Unit
LENGTH
1 kilometer (km) 1000 meters (m)
1 m 100 centimeters (cm)
1 cm 10 millimeters (mm)
MASS
1 kilogram (kg) 1000 grams (g)
1 g 1000 milligrams (mg)FIGURE 1.
A United States five cent piece has a mass of five grams.