1. Activity—Limits of Measurement
Classroom Activity

2. (1) Engagement Question: For the graduated cylinders shown below, what is the BEST answer for the volume of liquid shown?
(A) 50 ml
(B) 54 ml
(C) 53 ml
(D) 52.8 ml
(E) ml

3. (6) Why might this ruler offer an advantage over the first ruler?
Black block
(2)PAPER RULER
Closest measurement = 4cm
_____
(3)PLASTIC RULER
Closest measurement = 3.8 cm
(6) Why might this ruler offer an advantage over the first ruler?
More markings between 3 and 4 cm
Can now identify 0.1 cm’s or 1mm

4. (4 & 5) Counting Tick Marks
Inches
Plastic ruler = 15
Example Ruler = 7
Centimeters (cm)
Plastic ruler = 9
Example Ruler = 9
Minor Scale

5. Precision & Uncertainty
All measurements involve some degree of estimation. The more lines on a measuring tool (the lines are called graduations) the less of an estimate you have to make and the more “certain” you will be in your measurement. We call a measuring instrument that allows you to measure exactly (with certainty) a PRECISE measuring instrument. Measurements that are not precise are said to have a greater uncertainty. Uncertainty is normally NOT caused by the person doing the measurement but rather from the instrument itself.

6. (8, 9 & 10) Graduated Cylinders
Maximum Volume (mL)
Major Scale (mL)
Minor Scale (mL)
Volume present (mL)
1000
 100 10
 570
100
 10  1
 47
 0.2 or 0.1
 7.2

7. (11) Ranking Graduated Cylinder Precision
Greatest to least Precise
10ml
100ml
1000ml
Why?
10 ml has a smaller minor scale than the others

8. (12) …how many digits after the decimal should be shown on your volume reading for the elicitation question (# 1)? Explain why. Was your original answer correct or not?
52.8 ml is correct
Can only estimate one place past the minor scale or
Can only estimate to the tenths place

9. (13) Why would 52.85 ml be an incorrect reading for the volume contained in the graduated cylinder?
Can only estimate one place past the minor scale or
Can only estimate to the tenths place

10. (14) …The measurements are recorded as: (A) 8 cm. (B) 8. 1 cm. (C) 8
(14) …The measurements are recorded as: (A) 8 cm (B) 8.1 cm (C) 8.12 cm. Which of the instruments (A, B or C) is probably the MOST PRECISE? Explain your reasoning. C
Has more significant figures

11. (15) Explain how you can tell whether an instrument is precise by looking at the instrument itself.
The instrument has a small minor scale

12. (15 continued) Explain how you can tell whether an instrument is precise by looking at the data produced by the instrument.
The data has more significant figures