1. Measurements  Dimensions  Volume  Mass Miss Fogg Fall 2015

2. How to measure 1. Identify the units on the instrument 2. Line the object or place in spot for measurement 3. Read the certain digits 4. Read once between the lines to estimate the “uncertain” digit 6.0_ cm 5

3. Practice What is the length of the feather? _._ _cm 5 6 2

4. Triple Beam Balance Used to measure the mass of objects in grams (g)

5. Determining Mass 1. Place object on pan 2. Move riders along beam, starting with the largest, until the pointer is at the zero mark

6. Check to see that the balance scale is at zero

7. Triple Beam Balance 1. Place object on pan 2. Move riders along beam, starting with the largest, until the pointer is at the zero mark 3. Read the mass just as you would a ruler (all certain digits and one uncertain digit between the lines)

8. Read Mass _ _ _. _ _ g 272 ?

9. Read Mass More Closely _ _ _. _ _ g 27209

10. Graduated Cylinders Used to measure liquid volume in milliliters (mL) Have etches marks (read just like a ruler)

11. Measuring Liquid Volume Always read volume from the bottom of the meniscus. The meniscus is the curved surface of a liquid in a narrow cylindrical container.

12. Avoid Errors in Measurement Measure volume looking straight at the meniscus to avoid parallax errors Correct: Viewing the meniscus at eye level Incorrect: viewing the meniscus from an angle

13. Use the graduations to find all certain digits There are two unlabeled graduations below the meniscus, and each graduation represents 1 mL, so the certain digits of the reading are… 52 mL 52 mL.

14. Estimate the uncertain digit and take a reading The meniscus is about eight tenths of the way to the next graduation, so the final digit in the reading is. The volume in the graduated cylinder is 0.8 mL 52.8 mL.

15. 10 mL Graduate What is the volume of liquid in the graduate? _. _ _ mL 626

16. 25mL graduated cylinder What is the volume of liquid in the graduate? _ _. _ mL 115

17. 100mL graduated cylinder What is the volume of liquid in the graduate? _ _. _ mL 527

18. Self Test Examine the meniscus below and determine the volume of liquid contained in the graduated cylinder. The cylinder contains: _ _. _ mL 760