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Learn about qualitative and quantitative measurement, scientific notation, significant figures, rounding, temperature measurement, and the metric system with helpful examples and practice exercises.
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Scientific Measurement Qualitative measurement – give results in a descriptive, non-numeric form Quantitative measurement – give results in a definite form, usually numbers with units
Scientific Notation • the number is written as the product of two numbers: a coefficient and 10 raised to a power • the coefficient is always a number greater than or equal to 1 and less than 10 1,100,000 = 1.1 X 106 .00023 = 2.3 X 10-4 6,000 = 6.0 X 103
Practice! 1,204,523 = 1.20 X 106 4.7 X 105 = 470,000 75 = 7.5 X 101 3.0 X 108 = 300,000,000 1.23 = 1.23 X 100 0.000345 3.45 X 10-4= 0.000789 = 7.89 X 10-4 9.29 X 10-18 = 0.00000000000000000929
Significant Figures • Every nonzero digit is significant • Zeros between nonzero digits are significant • Zeros on the left in front of nonzero digits are not signficant – they are placeholders • Zeros at the end of a number and to the right of a decimal are always significant • Zeros at the right end of a measurement, but to the left of a decimal are not considered significant (unless they are known measured values)
Rounding Sig Figs • An answer cannot be more precise (have more sig figs) than the measured values used to obtain it • How to round: 1. decide how many sig figs the answer should have 2. Round to that many digits, counting from the left 3. If the digit to the right of the last sig digit is less than 5, drop it 4. If the digit to the right of the last sig digit is 5 or greater, increase the last digit by one
Measuring Temperature • Celsius: 0o - water freezes 100o - water boils
The Metric System • Prefixes: kilo 1,000 k hecto 100 h deka 10 da (unit) 1 (m,L,g) deci 1/10 d centi 1/100 c milli 1/1000 m
Units of the Metric System • Meter length m • Gram mass g • Liter volume L • Celsius temperature oC LARGER unit smaller unit decimal smaller unit LARGER unit decimal