1. Scientific Measurement SWBAT: Use scientific notation to show large & small numbers Describe the difference in Accuracy and Precision

2. Using & Expressing Measurements  Measurement – a quantity that has both a number and a unit  Scientific Notation – an expression of numbers in the form of m x 10 n  m is equal or grater than 1 and less than 10  n is an integer  6,300,000 =  0.000 008 = 6.3 x 10 6 8 x 10 -6

3. White Board Practice  Problem  6,234,000,000  0.000 024 56  15,010,000  1,000,000,000,000  0.000 000 067  0.003 02  987,600  Answer  6.234 x 10 9  2.456 x 10 -5  1.501 x 10 7  1.0 x 10 12  6.7 x 10 -8  3.02 x 10 -3  9.876 x 10 5

4. Accuracy, Precision & Error  Accuracy – a measure of how close a measurement comes to the actual or true value of whatever is measured  Precision – a measure of how close a series of measurements are to one another

5. White Board Practice  Three students make multiple determinations of the volume of a liquid, each using a different graduated cylinder. The correct volume of the liquid had been previously determined to be 86.22 mL. Describe the accuracy and precision of each student’s measurements. Volume of Liquid (mL) TrialElmerConstanceHenrietta 185.9482.7486.20 284.0282.6986.26 386.4882.6886.25 485.3582.7186.19 Elmer: Neither Constance: Precise Henrietta: Accurate & Precise

6. Determining Error  Accepted Value – correct value based on reliable references  Experimental Value – value measured in the lab  Percent Error – the accepted value minus the experimental error divided by the accepted value, multiplied by 100

7. White Board Practice  The correct volume of the liquid had been previously determined to be 86.22 mL.  Calculate the error using Elmer’s data from Trial 2. 86.22 – 84.02 = 2.2 = 0.0255 X 100 = 2.55% 86.2286.22 Volume of Liquid (mL) TrialElmer 185.94 284.02 386.48 485.35

8. White Board Practice  The correct volume of the liquid had been previously determined to be 86.22 mL.  Calculate the percent error using Henrietta’s data from Trial 3. Volume of Liquid (mL) Trial Henrietta 186.20 286.26 386.25 486.19 86.22 – 86.25 = -0.03 = -3.479 X 100 = 0.03% 86.22 86.22