The Metric System

1. The Metric System Length

2. The metric system is an international system of measurement. • All sciences use the metric system. • The United States is the only industrialized nation in the world that does not use the metric system as their official measurement. • Even though it is not our official system of measurement, we still use the metric system in various aspects of our lives.

3. Metric System • The three prefixes that we will use the most are: • kilo • centi • milli

4. Metric System • These prefixes are based on powers of 10. What does this mean? • From each prefix every “step” is either: • 10 times larger or • 10 times smaller • For example • Centimeters are 10 times larger than millimeters • 1 centimeter = 10 millimeters

5. Metric System • Centimeters are 10 times larger than millimeters so it takes more millimeters for the same length 1 centimeter = 10 millimeters Example not to scale 40 41 40 41 1 cm

6. Move right : multiply by a power of 10 for each step Move left: divide by a power of 10 for each step. Convert 4cm to mm You are moving right 1 step so you multiply by 10 4 x 10 = 40 4cm = 40mm Convert 5m to cm You are moving right 2 steps so you multiply by 100 5 x 100 = 500 5 meters – 500 cm Convert 34 mm to cm You are moving left 1 step So you divide by 10 34 ÷ 10 = 3.4 34 mm = 3.4 cm Convert 34 mm to m You are moving left 3 steps So you divide by 1000 34 ÷ 1000 -= .034 34 mm - .034 meters

7. Metric System • Now let’s start from centimeters and convert to kilometers 400000 centimeters = 4 kilometers 400000 centimeters = 4.00000 kilometers

8. Metric System • Now let’s start from meters and convert to centimeters 5 meters = 500 centimeters • Now let’s start from kilometers and convert to meters • .3 kilometers = 300 meters

9. Move right : multiply by a power of 10 for each step Move left: divide by a power of 10 for each step. You Try: 8 m = _____cm 92 cm = _____mm 120 cm = _____m 150 m =______km 44 mm = _____mm 7 km = ______m

10. Metric System • Summary • Base units in the metric system are meter, liter, gram • Metric system is based on powers of 10 • For conversions within the metric system, each “step” is 1 decimal place to the right or left • Using the diagram below, converting to the right, moves the decimal to the right and vice versa

11. Reading a Metric Ruler All metric rulers are numbered with centimeters (although they may show mm, cm, or metric)

12. The longer lines on the metric ruler are called… • centimeters

13. The shorter lines on the metric ruler are called… • millimeters

14. A B To read in centimeters write down how many whole centimeters and then each line after is .1 of a centimeter. Arrow A above is one line past 12 centimeters therefore it is 12. 1 cm. Arrow B is four lines past 15 centimeters therefore it is 15.4 cm

15. A B If you needed to measure in millimeters it is easier to measure in centimeters first and then convert to millimeters by multiplying by 10. Arrow A is 10.7 cm = 107 mm Arrow B is 14.1 cm = 141 mm

18. ______cm ______mm ______cm ______mm ______cm ______mm