Scientists use many skills as they investigate the world around them. They make observations by gathering information with
their senses. Some observations are simple. For example, a simple observation would be figuring out the color or texture of
an object. However, if scientists want to know more about a substance, they may need to take measurements.
Measurement is perhaps one of the most fundamental concepts in science. Without the ability to measure, it would be
difficult for scientists to conduct experiments or form theories. Not only is measurement important in science and the
chemical industry, it is also essential in farming, engineering, construction, manufacturing, commerce, and numerous
other occupations and activities.
The word “measurement” comes from the Greek word “metron,” which means “limited proportion.” Measurement is a
technique in which properties of an object are determined by comparing them to a standard.
Measurements require tools and provide scientists with a quantity. A quantity describes how much of something there is or
how many there are. A good example of measurement is using a ruler to find the length of an object. The object is
whatever you are measuring, the property you are trying to determine is the object’s length, and the standard you are
comparing the object’s length to is the ruler.
In general, scientists use a system of measurement still commonly referred to as the “metric system.” The metric system
was developed in France in the 1790s and was the first standardized system of measurement. Before that time, people
used a variety of measurement systems.
In 1960, the metric system was revised, simplified, and renamed the Système International d’Unites (International
System of Units) or SI system (meters, kilograms, etc.). This system is the standard form of measurement in almost
every country around the world, except for the United States, which uses the U.S. customary units system (inches,
quarts, etc.). The SI system is, however, the standard system used by scientists worldwide, including those in the
United States.
There are several properties of matter that scientists need to measure, but the most common properties are length and mass.
Length is a measure of how long an object is, and mass is a measure of how much matter is in an object. Mass and length
are classified as base units, meaning that they are independent of all other units. In the SI system, each unit of measure has
a base unit.
Explanation:
Some things scientists want to measure may be very large or very small. The SI, or metric, system is based on the
principle that all quantities of a measured property have the same units, allowing scientists to easily convert large and
small numbers. To work with such large or small numbers, scientists use metric prefixes. Prefixes can be added to base
units and make the value of the unit larger or smaller. For example, all masses are measured in grams, but adding
prefixes, such as milli- or kilo-, alters the amount. Measuring a human’s mass in grams would not make much sense
because the measurement would be such a large number. Instead, scientists use kilograms because it is easier to write
and say that a human has a mass of 90 kilograms than a mass of 90,000 grams. Likewise, one kilometer is 1,000 meters,
while one millimeter is 0.001 meters. The table below lists some common prefixes and the quantities they represent.
