290 Essential Skills for Health Careers Success
Measurement in Healthcare
When asked to measure something in the United States, most people
use the English system of measurement. Today, the United States is one of
the very few countries that have not converted to the metric system. The
rest of the world has adopted the metric system of measurement.
The main differences between the metric and English systems of mea-
surement can be found in the measurement units. The metric system uses
units organized by factors of ten. This allows the various types of units to
be related. Units of measurement in the English system are not related or
consistent. While the English system uses several different units, the metric
system has only three basic units: the gram, liter, and meter. In the metric
system, temperature is measured in degrees Celsius.
Calculations performed using the metric system are much easier than
calculations using the English system. For example, 1,000 meters are found
in 1 kilometer; however, there are 5,280 feet in a mile. In the English sys-
tem, there is no common base, which makes it challenging to use. The rela-
tionship between the different units of measure can be confusing because
English system units are not based in the powers of 10, as in the metric
system. For example, in the English system, the length of a yard was based
on the distance from King Henry I’s nose to his thumb.
For these reasons, the metric system is universally used in science and
medicine. Those who wish to have a career in the health sciences must
become comfortable using the metric system by understanding its termi-
nology, including its basic units and its prefi xes.
Metric Units
There are three basic units of measurement in the metric system—
grams, liters, and meters (Figure 10.16). The gram (g) is the basic metric
unit of measurement for weight. Weight is the physical measurement of an
English system of
measurement
a system of measurement
commonly used in the
United States; measure-
ments are based on the
inch, pound, gallon, and
Fahrenheit degrees
metric system of
measurement
a system of measurement
using units related by fac-
tors of ten; measurements
based on the gram, liter,
meter, and temperature
measured in Celsius
The History of Measurement
The English system of measurement was originally based on the
human body, nature, and everyday activities. For example, an acre
originally was a measure of land based on the amount of land that could be
plowed in a day. An inch was the width of a thumb. Such natural measures
were fi ne for a simple, agricultural society. However, as trade and commerce
grew, there was a need for more exact measures.
The metric system was developed by the French to create a system that
uses units related by factors of ten and only three basic measurements for
weight, volume, and length. When moving from one unit to another when
using the decimal system, simply move the decimal point to the appropriate
power of 10.