Digital Signal Processing Reference
In-Depth Information
Fig. 3.
Diagrammatic layout for the measurement
Release the sphere into the castor oil; and record the motion of the falling sphere
for 4~5 mins by web camera and then analyze the video by the Flash software to gain
some important data(see Table 1).
Table 1.
The data to determine the viscosity of castor oil
dmm
(
)
Δ
hpx
1
()
Δ
hcm
2
()
ypx
2
()
1
()
ypx
Δ=
t
(
t
−
t s
)( )
2
1
2.00
±
0.02
60
±
1
2.9
±
0.1
65
±
1
402
±
1
13.0
±
0.1
2.00
±
0.02
60
±
1
2.9
±
0.1
40
±
1
404
±
1
14.0
±
0.1
2.00
±
0.02
53
±
1
2.9
±
0.1
34
±
1
378
±
1
15.0
±
0.1
1.59
±
0.02
60
±
1
2.9
±
0.1
37
±
1
328
±
1
17.6
±
0.1
1.59
±
0.02
64
±
1
2.9
±
0.1
35
±
1
368
±
1
19.0
±
0.1
1.59
±
0.02
60
±
1
2.9
±
0.1
40
±
1
385
±
1
21.0
±
0.1
d
ΔΔ
12
,
hh
where
is the sphere's diameter,
is the distance of two scale lines on the vessel in
1
2
pixel coordinates and object coordinates,
is the pixel coordinates in the flash scene, and
yy
is the sphere's falling time .
Δ
t
Based on Equation (8) and the above data in Table 1,the value.
η =
1.154
±
0.002(
Pa s
)
(8)
The measured value of the coefficient of viscosity agrees to within 3% with the value
given in the Hand of Chemistry and Physics.
The measurement of the viscosity coefficient as a function of temperature can also
be a suitable experiment in an undergraduate laboratory. To explore the relationship
between temperature and viscosity coefficient, a heating and a temperature control
device are fixed on the vessel. Record the moving videos of the sphere at different
temperatures, and calculate the viscosity coefficient . Table 2 shows the experi-
ment result, and meanwhile the relationship is described by
η
η
T
curve in Figure 4.
9
−
0.07716
T
The experimental results
η
=
6.379
×
10
e
is obtained using the software
Matlab.
