How tall are you? How heavy is your backpack? You can answer these questions and many more by using weight-and-measurement tools. Find out which instruments are best for the job. The tools we use today are very different from the ones used long ago.

Measuring over Time

People have always needed to measure things. Long ago, they used the body and the world around them as guides. A "foot" was about the length of a man's foot. The arm, hand and finger were also used to determine length. Seeds, grains and stones were used to measure weight and volume. The sun, moon and stars were used to mark the passing of time.

But there was a problem with these tools. The results were not always the same. Over time, people came up with standard forms of measurement that gave exact results.

Setting the Standard

Our country's Founding Fathers believed a standard system of weights and measurements was important. The U.S. Constitution gives the lawmakers in Congress the power to set the standards.

In the U.S., length and distance are measured in inches, feet, yards and miles. Weight is measured in ounces and pounds. The U.S. has used this system for many years. But almost all other countries use the metric system. If you have measured in centimeters, you have used the metric system.

In 1975, Congress said the metric system was best for businesses. Do you agree?