Measurements and Calculations

Accuracy and Precision You must use the correct equipment Accuracy is how close you come to the desired value Precision is how close all of the data is to itself

Significant Figures The amount of rounding that is acceptable Calculators do not use significant figures Sig Figs are essential to reporting the results This discusses how certain one is of each number

Significant Figures Rules 1. ALL non-zero numbers are significant 2. All zeros between non-zero numbers are significant 3. Zeros to the right of a non-zero number are significant ONLY if a decimal is used 4. Zeros to the left of non-zero numbers are not significant

Significant Figures 46.3 All three numbers are significant 40.789 All five numbers are significant 7.890 All four numbers are significant 570.000 All six numbers are significant 0.0000000009887 Four numbers are significant

Significant Figures Multiplication and Division The answer must have the same number of significant figures as the measurement with the SMALLEST number of significant figures 12.257 x 1.162 = On the calculator it reads: 14.2426234 The measurement with the smallest number of sig figs is 1.162 with four sig figs, so round so the answer has four sig figs, or 14.24

Significant Figures Addition and subtraction The answer can be no more certain than the least certain number in the calculation

Scientific Notation This shows significant figures by condensing to a single digit decimal place 486,000,000,000 becomes 4.86 x 1011 .000 000 000 000 068 becomes 6.8 x 10-14 Must have single digit decimal place When the exponent is positive, the number is greater than 1 When the exponent is negative, the number is less than 1

Scientific Notation When putting scientific notation in the calculator, use the EE or EXP button, do not put x 10 ^ exponent If this is done, the calculation will be incorrect!