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Measurement

Measurement. Scientific Notation and the Metric System. Reliability in Measurement . Precision same results again and again under the same conditions Accuracy Close to the accepted value Accepted Value = the correct answer. The Metric System.

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Measurement

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  1. Measurement Scientific Notation and the Metric System

  2. Reliability in Measurement • Precision • same results again and again under the same conditions • Accuracy • Close to the accepted value • Accepted Value = the correct answer

  3. The Metric System • The United States uses the States Customary system (USCS), but most other countries use the International System of Units or the metric system. • The metric system uses a decimal system where all units are related by a factor of 10.

  4. Mass Length Time Count, quantity Temperature Electric current Luminous intensity Kilogram (kg) Meter (m) Second (s) Mole (mol) Kelvin (K) Ampere (A) Candela (cd) International System of Unit (SI Base Units)

  5. Area Volume Force Pressure Energy Power Voltage Frequency Electric charge m2 m3 Newton Pascal Joule Watt Volt Hertz coulomb Derived SI Units

  6. Giga Mega Kilo Hecto Deka Base Unit (m, g, L, sec, etc) deci centi milli micro nano pico G 109 M 106 k 103 h 102 da 101 100 d 10-1 c 10-2 m 10-3 u 10-6 n 10-9 p 10-12 Metric Prefixes

  7. Measurement to Scale

  8. Zeros appearing between nonzero digits are significant Zeros that appear in front of nonzero digits are not significant 2002_____ 1.00005 _____ 0.00006 _____ 00021 _____ Rules for Determining whether Zeros are significant

  9. Zero at the end of a number and to the right of a decimal are significant Zeros at the end of a number but to the left of a decimal are significant. Zeros at the end of a number with no decimal are not significant 5.00000 _____ 2.5000 _____ 5000. _____ 20 _____ 300 _____ Rules for Determining whether Zeros are significant Continued

  10. Rules for Multiplication and Division • The measurement with the smallest number of significant figures determines how many figures are allowed in the final answer. • 5.0 x 2.00 = ________ • 200.0 / 10.0 = ________

  11. Rules for Addition and Subtraction The number of significant figures allowed depends on the number with the least amount of digits after the decimal. • 100.00 + 3.2 = ______ • 5.3777 - .1 = ______ • 2500.00 +1.2 = ______

  12. Scientific Notation • A number written as the product of two numbers. • A coefficient • 10 raised to a power • Useful for large numbers. • For example 1g of hydrogen contains 602,000,000,000,000,000,000,000 atoms. • That is 6.02 x 1023 atoms.

  13. Converting to Scientific Notation • Moving the decimal to the left gives a positive exponent. • Example: 36,000= 3.6 x 104 • Moving the decimal to the right gives a negative exponent. • Example: 0.0081= 8.1 x 10-3

  14. 0.000137 = 3.2 x 105 = 1.72 x 10-3 = 1.37 x 10-4 320,000 0.00172 Try these on your own:

  15. Rules for Multiplication • Multiply the coefficients and add the exponents. • Example 1: (3.0 x 104) x (2.0 x 102) = 6.0 x 106 • Example 2: (4.0 x 10-7) x (1.0 x 102)= 4.0 x 10-5

  16. Rules for Division • Divide the coefficients and subtract the exponents. • Example 1: (3.0 x 104) / (2.0 x 102) = 1.5 x 102 • Example 2: (8.0 x 10-3) / (4.0 x 104) = 2.0 x 10-7

  17. Rules for Addition and Subtraction • Before you add or subtract in scientific notation, the exponents must be the same. • Example 1: 5.40 x 103 + 6.0 x 102 = • 54.0 x 102 + 6.0 x 102 = • 60.0 x 102 = 6.0 x 103 • Example 2: 8.5 x 10-2– 3.0 x 10-3= • 85 x 10-3- 3.0 x 10-3= • 82 x 10-3= 8.2 x 10-2

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