Today, most of the world does its measuring in the metric system, a simple system based on ten. One kilometer is one thousand meters. One meter is one hundred centimeters. And one centimeter is ten millimeters. The United States uses the imperial system created by the British. One mile equals 1,760 yards. One yard is three feet and one foot is 12 inches. While Britain switched to the metric system, people in the United States have stubbornly resisted moves to change our way of measuring things.
Class discussion: Does a system of meters, centimeters and millimeters make more sense to you than yards, inches and fractions of inches? Why or why not? Most other nations measure temperature using the Celsius system, where water freezes at 0 degrees and boils at 100 degrees. What is our Fahrenheit system based on? While base-ten systems may be used for many of the world’s measurements, how is time measured? Why are there 60 seconds in a minute, 60 minutes in an hour, 24 hours in a day or seven days in a week?