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Standards of Measurement. Standard – exact quantity that people agree to use to compare measurements. 2. Each measurement must include a. Number b. Unit Ex: 5 centimeters 1 gallon. 3. Two common systems of measurement: A. English System (foot, inches)
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Standard – exact quantity that people agree to use to compare measurements. 2. Each measurement must include a. Number b. Unit Ex: 5 centimeters 1 gallon
3. Two common systems of measurement: A. English System (foot, inches) B. Metric system (meter, centimeter)
International System of Units (SI) • Abbreviated SI • Developed in 1960 • Le SystemeInternationaled’Unites(French) • Universally accepted and understood by scientists throughout the world
Is the SI system more accuratethan the English System because scientists use it?
5. In the US, the National Institute of Standards maintains standards and sets style conventions. Ex. 75 000 vs 75,000 http://www.nist.gov/index.html
original meter = 1/10,000,000 of the distance from the North Pole to the equator but was off 0.2millimeter due to miscalculation of flattening of earth from today a meter = distance light travels in 1/299,792,458 of a second
Metric System Base 10 – scaled on multiples of 10 A) MULTIPLY by 10 – move decimal to the RIGHT a) 7.23 x 10 = 72.3 b) 9,786 x 100 = 978,600 c) 0.0045 x 1000 = 4.5
B) DIVIDE by 10 – move decimal to the LEFT a) 6.0/10 = 0.6 b) 9,786 / 100 = 9.786 c) 0.45 / 1000 = 0.00045