1. PERCENT ERROR, ACCURACY VS. PRECISION AND MEASURMENT

2. PERCENT ERROR Your Measured Value – Actual Value Actual Value X 100 Absolute Value sign: the difference cannot be negative

3. Problem # Basic EquationWorking Equation Given variablesSolve Answer  3 Sig figs  Sci Not.  Units Rectangle of Power!

4. Making sure you subtract the mass of the box, you re-measure the mouse and determine its real mass as 15.0 grams. What is the percent error? Example: You measure the mass of a mouse to be 14.6 grams. But because it is constantly jumping around you are not sure if you made an accurate measurement. SO: *No real mice were hurt in this example.

5. Problem # Example Basic EquationWorking Equation Given variablesSolve Answer  3 Sig figs  Sci Not.  Units Rectangle of Power! (M-A)/A x 100 M = 14.6g A =15.0g (14.6g - 15.0g 15.0g) X 100 2.67% error

6. ACCUR ACY PRECISI ON vs. Average is close to the actual number/value Grouped close together (small range)

7. ACCURACYPRECISIONvs.

8. ACCURACYPRECISIONvs.

9. Accurate, Precise or Neither 5.1 5.2 5.0 417 638 962 13.2412.9913.15 Accepte d Value: 5.14 Accepted Value: 10.25 Accepte d Value: 947 Trial 1Trial 2Trial 3 20.115.926.8 20.313.427.4 19.923.027.2 Accepted Value: 27.3 A P N PAPN P

10. DETERMINING: MASS & VOLUME

11. MASS Turn this knob to make sure balance is zeroed Tenths place Ones place Tens place Hundreds place

12. 100200300400500 102030405060708090 100 1 2 345678 9 10 100200300400500 102030405060708090 100 123456789 10 100200300400500 102030405060708090 100 1 2 3 4 56789 10 100200300400500 102030405060708090 100 123456789 10 140.5 g 74.8 g 500 g

13. 30 40 VOLUME GRADUATED CYLINDER VS. BURET MEASURES THE VOLUME OF A LIQUID What is this called? The menis cus! 33.5 mL MEASURES THE VOLUME OF A LIQUID RELEASED (USED IN TITRATIONS) 50 40 4.00 mL

14. 10 20 30 40 50 60 70 80 90 100 A B C D E

15. 100200300400500 102030405060708090 100 123456789 10 100200300400500 102030405060708090 100 123456789 10 100200300400500 102030405060708090 100 123456789 10 100200300400500 102030405060708090 100 123456789 10