SP015 Pre-Lab Experiment 1

SP015 Pre-Lab Module

EXPERIMENT 1: MEASUREMENT AND UNCERTAINTY
Read through the lab manual and then answer the following questions.

INTRODUCTION
1. Complete Table 1.

Basic Quantity Symbol SI Unit Measuring Instrument
(with symbol)

Length l

Mass m electronic balance, triple
beam balance

Time t

Electric Current I ampere, A

Temperature T

Table 1
2. ………..……………….……………….. is used to measure the diameter of a coin.

3. Micrometer screw gauge is usually used to measure the ………….……………… of a
thin wire or the ………………………………. of a paper.

4. Complete Table 2. Sensitivity Uncertainty
0.1 cm  0.1 cm
Measuring Apparatus 0.002 cm
Meter rule  0.01 mm
Vernier caliper 0.1 C  0.001 cm
Micrometer screw gauge 0.1 V
Travelling microscope  0.01 A
Thermometer 0.01 g
Voltmeter Table 2
Ammeter
Electronic Balance

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SP015 Pre-Lab Module

5. State TWO types of reading.
(i) ………………..……… reading
(ii) ……………………..… reading

6. The repeated readings for a measurement is recorded as a, b, c, d, e, and f. Write the
equation of average value and its uncertainty.

Quantity Equation

Average value, x

Uncertainty, x

EXPERIMENT
7. Complete Table 3.

Measurement Measuring Uncertainty Type of reading
Instrument / Smallest (single point /

scale two point /
vernier scale)

Length of a metal rod  0.1 cm Two points

Length and width of a Meter rule
laboratory book

Mass of a ball bearing  0.01 g Single point

Diameter of a coin Vernier scale
Vernier scale
Diameter of a ball Micrometer screw
bearing gauge

External diameter of a  0.01 mm
glass rod

Table 3

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SP015 Pre-Lab Module

8. Determine the reading for the following measurements.

(a)

0 cm 1 2 Main scale : ………………..
Vernier scale : ………………..

0 1 2 3 4 5 6 7 8 9 10 Actual reading: ………………..

Main Vernier
scale scale

(b) 11 cm Main scale : ………………..
Vernier scale : ………………..
10 cm Actual reading: ………………..

01 2 Main scale : ………………..
Vernier scale : ………………..
(c) Actual reading: ………………..

18 cm 19 cm

0 5 10

(d) Main scale : ………………..
Vernier scale : ………………..
45 Actual reading: ………………..
0

40

35

30

(e) Main scale : ………………..
Vernier scale : ………………..
5 Actual reading: ………………..
05

0

45

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SP015 Pre-Lab Module

9. The repeated readings of the diameter of a ball bearing, d are 2.50 mm, 2.52 mm,
2.51 mm and 2.50 mm.
(a) Calculate the average value of the diameter, d and its uncertainty, d . Record
the diameter in terms of its average value and uncertainty, (d  d).
Average value of the diameter,
d  d1  d2  d3  d4 
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Uncertainty of diameter, d  | d  d1 |  | d  d2 |  | d  d3 |  | d  d4 |
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d 

d 
Diameter of the ball bearing, d = ( ……………  …………… ) ……….

(b) What is the instrument or apparatus used for this measurement?
………………………………………………………………………………………

(c) From (a), calculate the volume of the ball bearing, V and its uncertainty, V.

Volume of ball bearing, Relative uncertainty of volume, V  3d
Vd

V  4 r 3 Uncertainty of volume, V   3d V
3 d 

V  4   d 3 V 
3 2

V  V 

V

(e) Record the volume, V in terms of its average value and uncertainty, (V  V ).
Volume of the ball bearing, V = ( ……………  …………… ) ……….

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DATA ANALYSIS SP015 Pre-Lab Module
10. Complete Table 4. D  Di (mm)

No. Diameter of ball bearing, L 
D ( 0.01 mm)
1
2 15.42
3 15.55
4 15.30
5 15.48
6 15.49
7 15.45
Average 15.55

L

Table 4

11. Record the diameter, D in terms of its average value (best value) and uncertainty,
(D  D).

Diameter of ball bearing, D = ( ……………  …………… ) ……….

12. Calculate its percentage of uncertainty.

Percentage of uncertainty of length, %  D   D 100%
D D

%  D  
D

%  D  
D

13. State THREE precautions of this experiment.
(i) ………………………………………………………………………………………
………………………………………………………………………………………
(ii) ………………………………………………………………………………………
………………………………………………………………………………………
(iii) ………………………………………………………………………………………
………………………………………………………………………………………

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