The Metric System

The System of Measurement for

Science

Measurement History

The ancient standard unit of measurement was the cubit, or the length of a person’s forearm from their elbow to their fingertips.

Measurement History

The British Imperial System of Measurement was created because people realized that body parts were not a good standard for measurement.

The British System includes inches, feet, ounces, and pounds.

The United States Customary System is based on the British System.

The Metric System - Background

The British Imperial System of Measurement was the traditional system of measurement until the 18th century.

The Metric System - Background

Scientists realized that there were problems with the British System:

1. There is no logical relationship between measures.

ex – There are 16 ounces in a pound and 2000 pounds in a ton.

2. It is difficult to perform the calculations to convert from one measurement to another.

Measurement History

Gabriel Mouton - a French vicar Wrote Observationes diametrorum solis et

lunae apparentium in 1670 Described a measurement system based on

the measurements of the size of the Earth System became the basis of the Metric

System

The Metric System - Background

Following the French revolution in 1791, French scientists agreed to create a system of measurement that everyone in the world would find easy to use.

The Metric System

The scientists calculated the distance from the equator to the North Pole and divided the distance into 10 million equal parts.

The Metric System

One part of this measurement equals the meter, the basic unit of measurement for the Metric System.

The Metric System

All units of measurement in the Metric System are compared to the standard measurement, the meter.

The Metric System

The gram is the basic unit of measurement for mass in the Metric System.

One gram is the amount of matter in a cube of water that measures 1/100 of a meter in length, width, and height.

Benefits of the Metric System

1. All units of measurement in the Metric System can be compared to each other using calculations that are based on the number 10.

– Ex – There are 100 centimeters in 1 meter. There are 1000 meters in 1 kilometer.

Benefits of the Metric System

2. There is only one unit for each type of measurement, unlike the English system that has many possible units:

Type of Measurement

Metric Unit English Unit

Time Second Second, minute, hour, day

Length Meter Inch, foot, yard, furlong, mile

Mass Kilogram Ounce, pound, ton

Benefits of the Metric System

3. Today, the United States is the only industrialized nation in the world that does not use the Metric System as their official system of measurement.

Burma also uses the Customary System, but it is not industrialized.

The Metric System in the U.S.

1866 – The use of the Metric System was made legal in the U.S. by the Metric Act of 1866.

1975 – The Metric Conversion Act of 1975 was passed by Congress and established the U.S. Metric Board to coordinate and plan the increasing use and voluntary conversion to the Metric System.

The Metric System in the U.S.

1988 – the Omnibus Trade and Competitiveness Act of 1988 designated the Metric System as the preferred measurement system and required each federal agency to use the Metric System by the end of 1992.

1991 – President George Bush signed Executive Order 12770, Metric Usage in Federal Government Programs that directed all executive departments and federal agencies to implement the use of the Metric System.

The Metric System in the U.S.

1994 – The Fair Packaging and Labeling Act by the FDA requires the use of dual units (English and Metric) on all consumer products.

1996 – All surface temperature observations in National Weather Service reports are now transmitted in degrees Celsius.

Type of Measurement

Definition Standard Unit Notes/How is it

measured?

Length The distance from one point to another

Mass The amount of matter in an object

Time An interval that passes between one event and the

next

Temperature A measure of the hotness of an object, related to the

average kinetic energy per molecule in the object

Volume The amount of space an object occupies

Measurement Comparison Chart