Skip Navigation
Share Share
The Metric System

The Metric System More correctly known as the International System of Units (abbreviated SI from the French language name Système International d'Unités), the metric system is the standardized method of measurements used by scientists world-wide. Designed during the French Revolution of the 1790's, it is now the official measurement standard used in most countries. In the United States, industrial use of SI is increasing, but popular use is still limited. In the United Kingdom, conversion to metric units is official policy but not yet complete.

(Source: http://en.wikipedia.org/wiki/International_System_of_Units)

What is the SI?

The metric system brought order out of the conflicting and confusing traditional systems of weights and measures being used in Europe.

  1. Why was the metric system designed?
  2. List the three conditions that units in the metric system (except for time and angular measure) must satisfy?
  3. What was selected as the original measuring stick?
  4. The metric system is easy to use because the units are based on what?

 

History

Important dates in the history of the modern metric system.

  1. When was a decimal system first proposed?
  2. What did Thomas Jefferson propose?
  3. Who authorized scientific investigations aimed at reforming French weights and measures?
  4. What organization produced the world's first decimal currency?
  5. When did France officially adopt the metric system?
  6. When was the International System of Units begun?
  7. What did Executive Order 12770 direct?
  8. When did the U. S. Stock Exchange begin decimal trading?
  9. On what date will dual labeling not be permitted in Europe?

 

What are the units?

Since implementation of the metric system, only two units have not been changed: time and angular measurement. Both were designed by the Babylonians with 60 as the base.

  1. There are seven SI base units for the seven base quantities. List the seven base quantities and their base units.

 

SI derived units

From the seven base quantities, other quantities were defined. These derived quantities were given derived units.

  1. List eight derived units and what they represent.

 

SI derived units with special names and symbols

For ease of understanding and convenience, 22 other derived units have been given special names and symbols.

  1. List the derived units for frequency, force, pressure, energy, power, and temperature.

 

SI derived units based on other derived units

Going even further: there are derived units where special names and symbols may themselves be included in the names and symbols of other derived units.

  1. List the derived units for moment of force, surface tension, angular velocity, heat capacity, and electric field strength.

 

Prefixes

Because all basic units equal one of those units, prefixes are added to the basic unit to show a change in size either larger or smaller.

  1. What is a metric prefix?
  2. What are the prefixes for the following numericals: mega- kilo- hecto- deka- deci- centi- milli- micro-

 

Common questions asked about the metric system

This site contains a series of frequently asked questions concerning the metric system.

  1. Is the metric system hard to learn or use?
  2. As stated in the amended Metric Conversion Act, what is still permitted "in nonbusiness activities" in the United States?
  3. Why should the United States convert to the metric system?

 

Toward a metric America

Even though the United States is the only major industrialized country in the world that does not use the metric system as its predominant system of measurement, its economy is based heavily on foreign trade.

  1. When did the United States sign the Treaty of the Meter?
  2. When did the United States adopt metric standards for length and mass?
  3. When will the United States eventually join the rest of the world in the use of the metric system of measurement?

 

Traveling outside the United States?

The hardest part of traveling outside of the US is knowing how the measurements compare to what we use. This site is an excellent one to help you understand those road signs, store quantities, and what the temperature really is when traveling in Europe or any where else.

  1. A road sign shows 150 km to Paris. How far would that be on your car's odometer?
  2. The speed limit is 120 km per hour. How fast should you be going?
  3. Your hostel is at an altitude of 1100 meters. How many feet above sea level is it?
  4. You can take 25 kg on the airplane as carry on. How many pounds can you take?
  5. The temperature in Munich is 23. Do you need a coat?

 

Although initially a thought change will be in order, the conversion of the United States from its presently used English system to the more widely metric system, will result in easier measurement and conversion, as well as increased participation in the world economy.

Author: DUANE DYER - Email duane.dyer@jordan.k12.ut.us