Scientific Measurement Qualitative measurement give results in a

Scientific Measurement Qualitative measurement – give results in a descriptive, nonnumeric form Quantitative measurement – give results in a definite form, usually numbers with units

Scientific Notation l l 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 6, 000 = 6. 0 X 103 . 00023 = 2. 3 X 10 -4

Practice! 1, 204, 523 = 1. 20 X 106 75 = 1. 23 = 7. 5 X 101 1. 23 X 100 0. 000789 = 7. 89 X 10 -4 4. 7 X 105 = 470, 000 3. 0 X 108 = 300, 000 3. 45 X 10 -4= 0. 000345 9. 29 X 10 -18 = 0. 000000000929

Significant Figures l l l 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 l l 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 l Celsius: 0 o 100 o - water freezes water boils

The Metric System l Prefixes: kilo hecto deka (unit) deci centi milli 1, 000 10 1 1/1000 k h da (m, L, g) d c m

Units of the Metric System l l Meter Gram Liter Celsius length mass volume temperature LARGER unit smaller m g L o. C unit decimal smaller unit LARGER unit decimal