2. Calibration, Temperature & Percent Error

3. What is Calibration? lines Calibration of measuring device is distance between two closest lines Not (Not distance between two closest #!)

4. Not all graduated cylinders are calibrated the same way

5. ? capacity of large graduated cylinder? ? calibration ? calibration of large graduated cylinder? 1000 ml 10 ml

6. Calibration = ? 1 ml source

7. Calibration = ? 1 ml

8. Calibration = ? 1 ml

9. Calibration = ? 0.2 ml

10. Here are some other pieces of lab equipment. Can you figure out the calibration of each?

11. meter stick: two closest lines are 1 millimeter apart

12. Calibration = ? 50 ml

13. Calibration = ? 25 ml

14. This is a triple beam balance

15. What’s the calibration? 0.1 gram

16. This is a buret [unlike graduated cylinder, numbers go down, so you read downwards] The calibration is: 0.1 ml

17. Temperature Scientifically speaking … The definition of temperature: Temperature is measure of average kinetic energy of particles in system

19. World’s Record Cold Temperatures Date ˚F ˚C World (Antarctica) Vostok II 7/21/1983 –129 –89 Verkhoyansk, Russia(Siberia) 2/7/1892 –94 –70 Asia Oimekon, Russia 2/6/1933 –90 –68 Greenland Northice 1/9/1954 –87 –66 N.A. Snag, Yukon, Canada 2/3/1947 –81 –63 U.S. Prospect Creek, Alaska 1/23/1971 –80 –62 U.S. (other than AK) Rogers Pass, Mont. 1/20/1954 –70 –56.5

20. Conversion formulas How can we convert from one temperature scale to another? K = °C + 273 (more precisely 273.15) °C = K – 273 [F = (9/5 °C) + 32]

21. Percent Error Ratio of an error to an accepted value % error = Error X 100% Accepted value

22. Error   measured value – accepted value  x 100% accepted value use absolute value – answer always positive

23. Data table 1.711.451.57 Trial 3 1.691.681.60 Trial 2 1.701.401.54 Trial 1 Student C (g/cm 3 ) Student B (g/cm 3 ) Student A (g/cm 3 ) Students were asked to find the density of sucrose [Sucrose has a density of 1.59 g/cm 3 ]

24. Let’s calculate the error 0.120.140.02 Trial 3 0.100.090.01 Trial 2 0.110.190.05 Trial 1 Student C (g/cm 3 ) Student B (g/cm 3 ) Student A (g/cm 3 ) Remember, the error is a positive number

25. Now let’s calculate the % error 7.58.81.26 Trial 3 6.35.70.63 Trial 2 6.911.93.14 Trial 1 Student C error Student B error Student A % error

26. Advantage of % Error Makes it easier to compare data, especially if comparing data from different trials