1. Significant Figures: Precision and Accuracy in Measurement http://en.wikipedia.org/wiki/Darts#mediaviewer/File:Darts_in_a_dartboard.jpgDarts in a dartboardPublic Domainview termsPublic Domain PeterPan23PeterPan23 - http://en.wikipedia.org/wiki/Image:Darts_in_a_dartboard.jpghttp://en.wikipedia.org/wiki/Image:Darts_in_a_dartboard.jpg http://commons.wikimedia.org/w iki/File%3AGlass_graduated_cy linders-set.jpgBy Lilly_M [GFDL (http://www.gnu.org/copyleft/fdl. html) or CC-BY-SA-3.0-2.5-2.0- 1.0 (http://creativecommons.org/lice nses/by-sa/3.0)], via Wikimedia Commons http://simple.wikipedia.org/wiki/Weighin g_scale#mediaviewer/File:Balance_Ker n.jpgBalance KernPublic DomainPublic Domain KareljKarelj - Own work

2. Target Practice You have 5 arrows. Mime shooting the bow. Be sure to make a “thwack” sound each time you shoot. Good luck!

3. Simple Bow

4. http://commons.wikimedia.org/wiki/File%3A25_Meter_Precision_and_50_Meter_Pistol_Target.sv gBy Caiguanhao [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

5. Was the shooter accurate? Was the shooter precise? Why or why not?

6. Compound Bow

7. http://commons.wikimedia.org/wiki/File%3A25_Meter_Precision_and_50_Meter_Pistol_Target.sv gBy Caiguanhao [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

8. Was the shooter accurate? Was the shooter precise? Why or why not?

9. Cross Bow

10. http://commons.wikimedia.org/wiki/File%3A25_Meter_Precision_and_50_Meter_Pistol_Target.sv gBy Caiguanhao [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

11. Was the shooter accurate? Was the shooter precise? Why or why not?

12. Which is Accurate? Which is Precise? Which are neither accurate nor precise? http://commons.wikimedia.org/wiki/File:Accuracy_and_precision_example.jpgPermission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License,GNU Free Documentation License

13. So, what do precision and accuracy mean in your labs? Precision is how close your lab measurements are to each other Accuracy is how close your measurements are to the correct value. http://commo ns.wikimedia.org/wiki/File %3A25_Met er_Precision _and_50_M eter_Pistol_ Target.svgB y Caiguanhao [GFDL (http://www. gnu.org/copy left/fdl.html) or CC-BY- SA-3.0-2.5- 2.0-1.0 (http://creativ ecommons.o rg/licenses/b y-sa/3.0)], via Wikimedia Commons

14. How do we express accuracy in measurement? We record the measurement according to the accuracy of the equipment used plus one estimated digit. http://commons.wikimedia.org/wiki/File%3AGlass_graduated_cylinder-50ml_pl.jpgBy Pleple2000 (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons http://fr.wikipedia.org/wiki/Balance_%28instrument%29#mediaviewer/Fichier:Bal ance_electronique%281%29.JPGBalance electronique(1)Domaine publicDomaine public

15. Remember: Estimate one digit between the lines. What is the correct reading for the cylinder? Meniscus Answer: 100. mL http://commons.wikimedia.org/wiki/File%3AMeasuring_cylinder.svgBy Lucasbosch (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons Read the bottom of the meniscus.

16. Least accurate Most accurate 665 mL 20.00 mL http://en.wikipedia.org/wiki/Meniscu s#mediaviewer/File:Meniscus.jpgMe niscusCC BY-SA 3.0CC BY-SA 3.0 PRHaneyPRHaney - Own work http://commons.wikimedia.org/wiki/File%3APlastic_grad uated_cylinder-1000ml.jpgBy Lilly_M [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0- 2.5-2.0-1.0 (http://creativecommons.org/licenses/by- sa/3.0)], via Wikimedia Commons Read the graduated cylinders correctly. Which cylinder is the

17. Which balance is more accurate? Estimated digit http://en.wikipedia.org/wiki/Weighing_scale#mediaviewer/Fil e:Analytical_balance_mettler_ae-260.jpgAnalytical balance mettler ae-260Public Domainview termsPublic Domain http://commons.wikimedia.org/wiki/File%3AWaga_elektroniczna.jpgBy Stan Zurek (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html), CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/) or CC-BY-SA-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/2.5-2.0-1.0)], via Wikimedia Commons

18. Rules for Significant Figures

19. Rule 1: Nonzeros are always signficant. Examples: 4.56 23 11,526 3 SF 2 SF 5 SF

20. Zeros are the problem!! There are 3 kinds of zeros: –CAPTURED: in the middle –PRECEDING: on the left –TRAILING: on the right

21. Rule 2: CAPTURED zeros are ALWAYS significant. Examples: 101 200,205 7802 3 SF 6 SF 4 SF

22. Rule 3: PRECEDING zeros are NEVER significant. Examples: 0.00101 0.200205 0.00007802 3 SF 6 SF 4 SF

23. Rule 4: TRAILING zeros are significant WITH A DECIMAL present. Examples: 100 100. 0.5000 105.75060 1 SF 3 SF 4 SF 8 SF Challenge: Write one hundred in 2 SF.

24. Significant Figures in Calculations http://en.wikipedia.org/wiki/TI- 84_Plus_series#mediaviewer/File:TI- 84_Plus_Silver_Edition.JPGTI-84 Plus Silver EditionPublic DomainPublic Domain

25. Multiplying and Dividing Rule 5: When multiplying or dividing the answer will have the same SF as the least accurate measurement. Example: m = 9.567 g V = 10.1 mL D = m/V = 9.567g/10.1 mL = = 0.9472277228 g/mL 0.947 g/mL Note the use of Given, Formula, Substitute, Solve 3 SF http://www.dreamstime.co m/royalty-free-stock- photos-icon-multiply- divide-image10996788

26. Rule 6: Counted, known, and accepted values DO NOT affect significant figures. Example: (20 students)(68.18 kg avg. mass) = 1363.6 kg Round answer to 4 sig figs. = 1364 Kg Least accurate measurement Counted value has no affect

27. Adding and Subtracting Rule 7: When adding and subtracting, the answer is rounded to most accurate decimal place shared by all the measurements. Example:209.7cm 8.004cm + 1012.39 cm 1230.094cm Tenths column is the most accurate decimal place shared by all the measurements, so round to tenths. Final answer: 1230.1 cm

28. …for now… http://commons.wikimedia.org/wiki/File%3ALittle_Gray_Mouse_- _The_End_(67).pngBy Dorothy Sherrill (Internet Archive) [Public domain or Public domain], via Wikimedia Commons