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What is Science

Learn about the scientific method, measurement in science using scientific notation, and the metric system. Understand significant figures and accuracy vs precision.

carlgraham
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What is Science

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  1. What is Science • Study of the physical universe • An organized body of facts • Experimentation • Observation • Cannot be vague • Avoid inference

  2. Scientific Method – is a problem solving process • Define the problem – ask a question • Form a hypothesis – educated guess • Test the hypothesis – use the tools of science • Accept or reject hypothesis – evaluate data • Reformulate hypothesis • Verify hypothesis - retest

  3. 1.3 The Scientific Method Steps in the Scientific Method

  4. Measurement in Science • Scientific Notation – a shorthand method for writing very large and small numbers • Metric System – an international measurement system that uses the decimal system units of division (base 10) • Significant Figures – any measurement which is reliable

  5. Scientific Notation • Numbers are expressed as a value between 1 and 10 (not 10) times 10 raised to a power • Example 215,067 Flowers = • Example .000567 grams =

  6. Scientific Notation • Addition and Subtraction – exponents must have the same value ● Multiplication – add exponents ● Division – subtract exponents

  7. Addition and Subtraction 7.55 x 10 -7 +2.45 x 10 -5 Must change exponents to match 7.55 x 10 -7 + 245. x 10 -7 Note: the exponent got 252.55 x 10 -7 smaller so the number gets bigger Subtraction follows the same rule

  8. Multiplication – add exponents 5.39 x 10 5 x 3.21 x 10 3 17.30 x 10 8 Note: the answer is not in proper scientific notation 1.73 x 10 9 Proper Scientific Notation

  9. Division – subtract exponents 7.26 x 10 5÷ 3.21 x 10 3 = 226 Note: the answer is not in proper scientific notation 2.26 x 10 2 Proper Scientific Notation 2.08 x 10 -6 = 0.648 x 10 -1 3.21 x 10-5 Note: the answer is not in proper scientific notation 6.48 x 10 -2Proper Scientific Notation

  10. Metric System • Basic Units • Meter – length • Gram – mass • Cubic decimeter (or Liter) – volume • Kelvin (or Celsius) – temperature • Seconds – time • Joules – energy

  11. Metric System Prefixes • kilo - 103 - 1000 times basic unit • hecto - 102 - 100 times basic unit • deka – 101 – 10 times basic unit • deci - 10-1 - 0.1 times basic unit • centi -10-2 - 0.01 times basic unit • milli - 10-3 - 0.001 times basic unit • micro - 10-6 - 0.000001 times basic unit Metric converter - is helpful when learning conversions

  12. Metric Converter Smaller Prefix Factor Scientific Notation units nano (n) 1/1,000,000,000 10 -9 micro (m) 1/1,000,000 10 -6 milli (m) 1/1000 10 -3 centi (c) 1/100 10 -2 deci (d) 1/10 10 -1 Standard (Meter, Liter, 1 10 0 unit Gram) deka (D) 10 10 1 hecto (h) 100 10 2 kilo (k) 1000 10 3mega (M) 1,000,000 10 6giga (G) 1,000,000,000 10 9 Larger Units Decimal Point Movement

  13. Significant Figures (digits) • Accuracy – difference between a measured value and the true or accepted value • Precision – degree of agreement between measured values

  14. Accuracy vs. Precision Accurate Precise Accurate and Precise Note: The accurate target is not precise but the average of the values is accurate

  15. Significant Figures • Rules for defining significant figures - Leading zeros are not significant Ex: 0.000025 • Trailing zeros are not significant unless there is a decimal point following them Ex: 2500000 • Captive zeros are always significant • Zeros to the right of a decimal and a non-zero number are always significant

  16. 5 A useful rule of thumb to use for determining whether or not zeros are significant figures is that zeros are not sig. fig. if the zeros disappear when scientific notation is used. E.g.0.0197 = 1.97 x10-2 the zeros are not sig. fig.; 0.01090 = 1.090 x10-2 the first two zeros are not significant and the second two are. The number 0.004004500 has 7 sig. Fig.

  17. Significant Figures • Rules of Operations • Addition and subtraction – the limiting term is the one with the smallest number of decimal places to the right 6.345 1.00945 +0.125045- 0.210 6.470 0.799

  18. Significant Figures • Rules of Operation (cont.) • Multiplication and division – the answer contains the same number of significant figures as the value with the smallest number of significant figures 9.110 0.4521= 0.374 x 0.025 1.21 0.23 2 sig. figs. 3 sig. figs

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