The Metric System

1. The Metric System

2. Metric System • System used by scientists to measure length, mass, volume, density and temperature • Used in nearly every country in the world the metric system was devised by French scientists in the late 18th century. • A standard is an exact quantity that people agree to use for comparison. Measurements using the same standard can be compared to each other.

3. The SI System (The Metric System)

4. Metric System Metric system – Known as the international system of units (SI). All SI standards are accepted and used by scientists all over the world. (Standards are kept at the International Bureau of Weights and Measures in Sevres France) • A decimal system • Based on number 10 and multiples of 10 • Base unit is made larger or smaller by adding prefixes

5. Metric System Base Unit • Meter (m) – used to measure length • Liter (L) – used to measure volume • Gram (g) – used to measure mass

6. Metric System • Length – The distance between two points. • One meter is the distance light travels in a vacuum in 1/299 792 458 second (3.37 inches longer than a yard). • The speed of light, a universal constant, is almost exactly 300 megameters per second (3.0 x 108 m/s). • Length is measured using a meter stick or metric ruler.

7. Metric System Volume – The amount of space an object takes up. One liter is slightly more than one quart. The volume of a rectangular prism is L x W x H Volume can also be measured using a graduated cylinder.

8. Metric Volume: Cubic Meter (m3) 10 cm x 10 cm x 10 cm = Liter

9. Metric System • Mass – The amount of matter in an object. • 1 kg = 2.2 pounds • The mass of the earth is 5983 Yg (yottagrams), and it gains another 40 Gg (gigagrams) (40,000,000 kg = 88,000,000 lbs) every year from captured meteorites and cosmic dust. • The mass of a proton is about 1.67 yg (yoctograms), and that of an electron about 0.000 91 yg (yoctograms). • Mass is measured using a triple beam balance or a scale.

10. Metric System Metric Conversions • Numbers in the metric system are made larger or smaller by adding prefixes to the base unit. The base unit determines whether the measurement involves mass, volume or length. • m L g - if only one letter, it is a base unit

11. The Stair-step Kilo- k King Hecto- h Henry Deka- da died base units- by Deci- d drinking Centi- c chocolate Milli- m milk Grams, liters, meters

12. How Do I Use This? • The first letter of the prefix in the unit of measurement tells you which step to start on. The first letter in the second unit of measurement tells you which step to stop on. • Find which step to start on, and count the number of steps it takes to get to the step that you need to stop on.

13. How Do I Use This? • If you went to the right (downstairs) the decimal in the first measurement moves that many places to the right. • If you went to the left (upstairs) then the decimal moves to the left. Fill any empty places with zeros.

14. 525568 mm = ? hm To make the conversion, we start on the milli- step and go five steps to the left to get to the hecto- step. Therefore, the decimal in 525568 mm moves five places to the left, becoming . . . . . . . 5.25568 m

15. .00654 kg = ? g We would start on the Kilo- step and move three steps to the right this time, ending on the gram (base unit) step. Therefore, .00654 kg becomes . . . . 6.54 g

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