PASCO TD-8555 User Manual
Includes
Teacher's Notes
and
Typical
Experiment Results
RADIATION SYSTEM
Instruction Manual and
Experiment Guide for the
PASCO scientific
Model TD-8553/8554A/8555
THERMAL
TD-8554A Radiation Cube
(Leslie's Cube)
012-04695D
03/99
TD-8555
STEFAN-BOLTZMAN
LAMP
CAUTION
13 VDC MAX LAMP VOLTAGE
FOR MAXIMUM ACCURACY,
MEASURE VOLTAGE AT
BINDING POSTS
USE NO.1196 BULB
TD-8555 Stefan
Boltzman Lamp
CAUTION: HOT!
ON
OFF
4
5
3
2
1
LOW HIGH
R
O
T
IS
M
R
E
N
H
T
IO
T
A
4
!
5
U
5
T
A
-8
D
O
100W
T
C
l
e
H
d
o
BULB
M
MAX.
6
7
8
(LESLIE'S CUBE)
TD-8553 Radiation Sensor
© 1988 PASCO scientific $5.00
Thermal Radiation 012-04695D
The lightning flash with arrowhead,
within an equilateral triangle, is intended
to alert the user of the presence of
uninsulated “dangerous voltage” within
the product’s enclosure that may be of
sufficient magnitude to constitute a risk
of electric shock to persons.
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
CAUTION:
TO PREVENT THE RISK OF
ELECTRIC SHOCK, DO NOT
REMOVE BACK COVER. NO USER
SERVICEABLE PARTS INSIDE.
REFER SERVICING TO QUALIFIED
SERVICE PERSONNEL.
The exclamation point within an equilateral triangle is intended to alert the
user of the presence of important
operating and maintenance (servicing) instructions in the literature accompanying the appliance.
2
012-04695D Thermal Radiation System
T able of Contents
Section...................................................................................................... Page
Copyright and Warranty, Equipment Return.................................................. ii
Introduction .....................................................................................................1
Radiation Sensor..............................................................................................1
Thermal Radiation Cube (Leslie’s Cube)........................................................2
Stefan-Boltzmann Lamp..................................................................................3
Experiments:
Experiment 1: Introduction to Thermal Radiation ...................................5
Experiment 2: Inverse Square Law ..........................................................9
Experiment 3: Stefan-Boltzmann Law (high temperature) .....................13
Experiment 4: Stefan-Boltzmann Law (low temperature) .....................17
Teacher’s Guide.............................................................................................19
Technical Support................................................................Inside Back Cover
i
Thermal Radiation System 012-04695D
Copyright, Warranty, and Equipment Return
Please—Feel free to duplicate this manual
subject to the copyright restrictions below.
Copyright Notice
The PASCO scientific Model TD 8553/
8554A/8555 Thermal Radiation System manual is
copyrighted and all rights reserved. However, permission is granted to non-profit educational institutions for
reproduction of any part of the manual providing the
reproductions are used only for their laboratories and
are not sold for profit. Reproduction under any other
circumstances, without the written consent of PASCO
scientific, is prohibited.
Limited Warranty
PASCO scientific warrants the product to be free from
defects in materials and workmanship for a period of
one year from the date of shipment to the customer.
PASCO will repair or replace at its option any part of
the product which is deemed to be defective in material
or workmanship. The warranty does not cover damage
to the product caused by abuse or improper use.
Determination of whether a product failure is the result
of a manufacturing defect or improper use by the
customer shall be made solely by PASCO scientific.
Responsibility for the return of equipment for warranty
repair belongs to the customer. Equipment must be
properly packed to prevent damage and shipped postage or freight prepaid. (Damage caused by improper
packing of the equipment for return shipment will not
be covered by the warranty.) Shipping costs for returning the equipment after repair will be paid by PASCO
scientific.
Credits
Equipment Return
Should the product have to be returned to PASCO
scientific for any reason, notify PASCO scientific by
letter, phone, or fax BEFORE returning the product.
Upon notification, the return authorization and shipping instructions will be promptly issued.
ä
NOTE: NO EQUIPMENT WILL BE
ACCEPTED FOR RETURN WITHOUT AN
AUTHORIZATION FROM PASCO.
When returning equipment for repair, the units must be
packed properly. Carriers will not accept responsibility
for damage caused by improper packing. To be certain
the unit will not be damaged in shipment, observe the
following rules:
➀ The packing carton must be strong enough for the
item shipped.
➁ Make certain there are at least two inches of pack-
ing material between any point on the apparatus and
the inside walls of the carton.
➂ Make certain that the packing material cannot shift
in the box or become compressed, allowing the
instrument come in contact with the packing carton.
Address: PASCO scientific
10101 Foothills Blvd.
Roseville, CA 95747-7100
Phone: (916) 786-3800
FAX: (916) 786-3292
email: techsupp@pasco.com
web: www.pasco.com
This manual authored by: Bruce Lee
Teacher’s guide written by: Eric Ayres
ii
012-04695D Thermal Radiation System
Introduction
The PASCO Thermal Radiation System includes three
items: the TD-8553 Radiation Sensor, the TD-8554A
Radiation Cube (Leslie's Cube), and the TD-8555
Stefan-Boltzmann Lamp. This manual contains
operating instructions for each of these items plus
instructions and worksheets for the following four
experiments:
① Introduction to Thermal Radiation,
② Inverse Square Law,
③ Stefan-Boltzmann Law* (at high temperatures),
④ Stefan-Boltzmann Law* (at low temperatures).
* The Stefan-Boltzmann law states that the radiant
energy per unit area is proportional to the fourth
power of the temperature of the radiating surface.
Radiation Sensor
The PASCO TD-8553 Radiation Sensor (Figure 1)
measures the relative intensities of incident thermal
radiation. The sensing element, a miniature thermopile, produces a voltage proportional to the intensity of
the radiation. The spectral response of the thermopile
is essentially flat in the infrared region (from 0.5 to 40
µm), and the voltages produced range from the microvolt range up to around 100 millivolts. (A good
millivolt meter is sufficient for all the experiments
described in this manual. See the current PASCO
catalog for recommended meters.)
In addition to the equipment in the radiation system,
several standard laboratory items, such as power
supplies and meters are needed for most experiments.
Check the experiment section of this manual for
information on required equipment.
If you don't have all the items of the radiation system,
read through the operating instructions for the equipment you do have, then check the experiment section
to determine which of the experiments you can perform. (A radiation sensor is required for all the
experiments.)
The two posts extending from the front end of the
Sensor protect the thermopile and also provide a
reference for positioning the sensor a repeatable
distance from a radiation source.
Specifications
Temperature Range: -65 to 85 °C.
Maximum Incident Power: 0.1 Watts/cm2.
Spectral Response: .6 to 30µm.
Signal Output: Linear from 10-6 to 10-1 Watts/cm2.
The Sensor can be hand held or mounted on its stand
for more accurate positioning. A spring-clip shutter is
opened and closed by sliding the shutter ring forward
or back. During experiments, the shutter should be
closed when measurements are not actively being
taken. This helps reduce temperature shifts in the
thermopile reference junction which can cause the
sensor response to drift.
ä
NOTE: When opening and closing the
shutter, it is possible you may inadvertently
change the sensor position. Therefore, for
experiments in which the sensor position is
critical, such as Experiment 3, two small sheets
of opaque insulating foam have been provided.
Place this heat shield in front of the sensor when
measurements are not actively being taken.
Shutter Ring: Slide
forward to open
shutter
Shutter
1
Thumbscrew: Loosen to
reposition Sensor or to
remove Sensor from stand
Banana Connectors:
Connect to millivolt meter
Figure 1 Radiation Sensor
Thermal Radiation System 012-04695D
Thermal Radiation Cube (Leslie’s Cube)
The TD-8554A Radiation Cube (Figure 2) provides
four different radiating surfaces that can be heated
from room temperature to approximately 120 °C. The
cube is heated by a 100 watt light bulb. Just plug in
the power cord, flip the toggle switch to “ON”, then
turn the knob clockwise to vary the power.
Measure the cube temperature by plugging your
ohmmeter into the banana plug connectors labeled
THERMISTOR. The thermistor is embedded in one
corner of the cube. Measure the resistance, then use
Table 1, below, to translate the resistance reading into a
temperature measurement. An abbreviated version of
this table is printed on the base of the Radiation Cube.
ä
NOTE: For best results, a digital ohmmeter
should be used. (See the current PASCO catalog
for recommended meters.)
ä
IMPORTANT: When replacing the light
bulb, use a 100-Watt bulb. Bulbs of higher
power could damage the cube.
CAUTION: Cube may be HOT!
Flip toggle
switch to
“ON” to turn
on power.
CAUTION: HOT!
ON
OFF
Figure 2 Radiation Cube (Leslie's Cube)
Turn knob
clockwise to
increase
temperature.
100W
BULB
4
5
MAX.
3
6
2
7
1
8
LOW HIGH
To 115
IST
N
THERM
O
I
T
!
U
T
A
O
T
C
l
e
H
d
o
M
E
I
L
S
E
L
(
or
200
VAC
Banana
OR
-8
D
'S
A
4
5
5
)
E
B
U
C
Connectors:
Measure
thermistor
resistance.
Use table on
back to
determine
cube
temperature.
Therm. Temp.
Res. (Ω) (°C)
207,850 10
197,560 11
187,840 12
178,650 13
169,950 14
161,730 15
153,950 16
146,580 17
139,610 18
133,000 19
126,740 20
120,810 21
115,190 22
109,850 23
104,800 24
100,000 25
95,447 26
91,126 27
87,022 28
83,124 29
79,422 30
75,903 31
72,560 32
69,380 33
Table 1
Resistance versus Temperature for the Thermal Radiation Cube
Therm. Temp.
Res. (Ω) (°C)
66,356 34
63,480 35
60,743 36
58,138 37
55,658 38
53,297 39
51,048 40
48,905 41
46,863 42
44,917 43
43,062 44
41,292 45
39,605 46
37,995 47
36,458 48
34,991 49
33,591 50
32,253 51
30,976 52
29,756 53
28,590 54
27,475 55
26,409 56
25,390 57
Therm. Temp.
Res. (Ω) (°C)
24,415 58
23,483 59
22,590 60
21,736 61
20,919 62
20,136 63
19,386 64
18,668 65
17,980 66
17,321 67
16,689 68
16,083 69
15,502 70
14,945 71
14,410 72
13,897 73
13,405 74
12,932 75
12,479 76
12,043 77
11,625 78
11,223 79
10,837 80
10,467 81
Therm. Temp.
Res. (Ω) (°C)
10,110 82
9,767.2 83
9,437.7 84
9,120.8 85
8,816.0 86
8,522.7 87
8,240.6 88
7,969.1 89
7,707.7 90
7,456.2 91
7,214.0 92
6,980.6 93
6,755.9 94
6,539.4 95
6,330.8 96
6,129.8 97
5,936.1 98
5,749.3 99
5,569.3 100
5,395.6 101
5,228.1 102
5,066.6 103
4,910.7 104
4,760.3 105
Therm. Temp.
Res. (Ω) (°C)
4,615.1 106
4,475.0 107
4,339.7 108
4,209.1 109
4,082.9 110
3,961.1 111
3,843.4 112
3,729.7 113
3,619.8 114
3,513.6 115
3,411.0 116
3,311.8 117
3,215.8 118
3,123.0 119
3,033.3 120
2,946.5 121
2,862.5 122
2,781.3 123
2,702.7 124
2,626.6 125
2,553.0 126
2,481.7 127
2,412.6 128
2,345.8 129
Therm. Temp.
Res. (Ω) (°C)
2,281.0 130
2,218.3 131
2,157.6 132
2,098.7 133
2,041.7 134
1,986.4 135
1,932.8 136
1,880.9 137
1,830.5 138
1,781.7 139
1,734.3 140
1,688.4 141
1,643.9 142
1,600.6 143
1,558.7 144
1,518.0 145
1,478.6 146
1,440.2 147
1,403.0 148
1,366.9 149
1,331.9 150
2
012-04695D Thermal Radiation System
Stefan-Boltzmann Lamp
IMPORTANT: The voltage into the lamp
should NEVER exceed 13 V. Higher voltages
will burn out the filament.
The TD-8555 Stefan-Boltzmann Lamp (Figure 3) is a
high temperature source of thermal radiation. The
lamp can be used for high temperature investigations
of the Stefan-Boltzmann Law. The high temperature
simplifies the analysis because the fourth power of the
ambient temperature is negligibly small compared to
the fourth power of the high temperature of the lamp
filament (see Experiments 3 and 4). When properly
oriented, the filament also provides a good approximation to a point source of thermal radiation. It therefore
works well for investigations into the inverse square
law.
By adjusting the power into the lamp (13 Volts max, 2
A min, 3 A max), filament temperatures up to approximately 3,000 °C can be obtained. The filament
temperature is determined by carefully measuring the
voltage and current into the lamp. The voltage divided
by the current gives the resistance of the filament.
Banana Connectors:
Connect to Power
Supply – 13 V MAX,
(2 A min, 3 A max)
TD-8555
STEFAN-BOLTZMAN
LAMP
CAUTION
13 VDC MAX LAMP VOLTAGE
FOR MAXIMUM ACCURACY,
PASCO scientific
MEASURE VOLTAGE AT
BINDING POSTS
USE NO.1196 BULB
Figure 3 Stefan-Boltzmann Lamp
Equipment Recommended
AC/DC LV Power Supply (SF-9584) or equivalent
capable of 13 V @ 3 A max
R - R
aR
ref
ref
ref
ref
T = + T
For small temperature changes, the temperature of
the tungsten filament can be calculated using a, the
temperature coefficient of resistivity for the filament:
where,
T = Temperature
R = Resistance at temperature T
T
= Reference temperature (usually room temp.)
ref
R
= Resistance at temperature T
ref
a = Temperature coefficient of resistivity for the
filament (α = 4.5 x 10-3 K-1 for tungsten)
For large temperature differences, however, a is not
constant and the above equation is not accurate.
REPLACEMENT BULB: GE Lamp No. 1196,
available at most auto parts stores.
ä
NOTE: When replacing the bulb, the leads
should be soldered to minimize resistance.
For large temperature differences, therefore, determine the temperature of the tungsten filament as
follows:
① Accurately measure the resistance (R
) of the tung-
ref
sten filament at room temperature (about 300 °K).
Accuracy is important here. A small error in R
ref
will result in a large error in your result for the filament temperature.
② When the filament is hot, measure the voltage and
current into the filament and divide the voltage by
the current to measure the resistance (R
③ Divide R
(RT/R
by R
T
).
ref
to obtain the relative resistance
ref
).
T
④ Using your measured value for the relative resistiv-
ity of the filament at temperature T, use Table 2 on
the following page, or the associated graph, to determine the temperature of the filament.
3
Thermal Radiation System 012-04695D
Table 2 Temperature and Resistivity for Tungsten
Temp
R/R
300K
°K
Resistivity
µΩ cm
R/R
300K
Temp
°K
Resistivity
µΩ cm
R/R
300K
Temp
°K
Resistivity
µΩ cm
R/R
300K
Temp
°K
Resistivity
µΩ cm
1.0
1.43
1.87
2.34
2.85
3.36
3.88
4.41
4.95
300
400
500
600
700
800
900
1000
1100
5.65
8.06
10.56
13.23
16.09
19.00
21.94
24.93
27.94
20
19
18
17
16
15
14
5.48
6.03
6.58
7.14
7.71
8.28
8.86
9.44
10.03
1200
1300
1400
1500
1600
1700
1800
1900
2000
30.98
34.08
37.19
40.36
43.55
46.78
50.05
53.35
56.67
10.63
11.24
11.84
12.46
13.08
13.72
14.34
14.99
15.63
2100
2200
2300
2400
2500
2600
2700
2800
2900
60.06
63.48
66.91
70.39
73.91
77.49
81.04
84.70
88.33
Temperature versus Resistivity for Tungsten
16.29
16.95
17.62
18.28
18.97
19.66
26.35
3000
3100
3200
3300
3400
3500
3600
92.04
95.76
99.54
103.3
107.2
111.1
115.0
Relative
Resistivity
R
T
R
300K
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0 500 1000 1500 2000 2500 3000 3500
Temperature (Kelvin)
4
012-04695D Thermal Radiation System
Experiment 1: Introduction to Thermal Radiation
EQUIPMENT NEEDED:
— Radiation Sensor, Thermal Radiation Cube — Window glass
— Millivoltmeter — Ohmmeter.
ä
NOTES:
① If lab time is short, it's helpful to preheat the cube at a setting of 5.0 for 20 minutes before
the laboratory period begins. (A very quick method is to preheat the cube at full power
for 45 minutes, then use a small fan to reduce the temperature quickly as you lower the
power input. Just be sure that equilibrium is attained with the fan off.)
② Part 1 and 2 of this experiment can be performed simultaneously. Make the measure-
ments in Part 2 while waiting for the Radiation Cube to reach thermal equilibrium at each
of the settings in Part 1.
③ When using the Radiation Sensor, always shield it from the hot object except for the few
seconds it takes to actually make the measurement. This prevents heating of the thermopile which will change the reference temperature and alter the reading.
Radiation Rates from Different Surfaces
Part 1
① Connect the Ohmmeter and Millivoltmeter as shown in Figure 1.1.
② Turn on the Thermal Radiation Cube and set
the power switch to “HIGH”. Keep an eye on
the ohmmeter reading. When it gets down to
about 40 kΩ, reset the power switch to 5.0. (If
the cube is preheated, just set the switch to 5.0.)
③ When the cube reaches thermal equilibrium—
the ohmmeter reading will fluctuate around a
relatively fixed value—use the Radiation
Sensor to measure the radiation emitted from
each of the four surfaces of the cube. Place
the Sensor so that the posts on its end are in
contact with the cube surface (this ensures that
the distance of the measurement is the same for
all surfaces). Record your measurements in the
appropriate table on the following page. Also
measure and record the resistance of the thermistor. Use the table on the base of the cube to
determine the corresponding temperature.
CAUTION: HOT!
ON
OFF
A
100W
C
H
BULB
4
5
MAX.
3
6
2
7
1
8
LOW HIGH
Ohmmeter
R
O
T
IS
M
R
E
N
H
T
O
I
T
A
4
!
5
U
5
T
8
-
D
O
T
l
e
d
o
M
)
E
B
U
C
'S
IE
L
S
E
(L
Millivoltmeter
④ Increase the power switch setting, first to
6.5, then to 8.0, then to “HIGH”. At each
Figure 1.1 Equipment Setup
setting, wait for the cube to reach thermal equilibrium, then repeat the measurements
of step 1 and record your results in the appropriate table.
5
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