PASCO TD-8513 User Manual
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Instruction Manual
012-09189A
Heat Conduction Apparatus
TD-8513
Heat Conduction Apparatus Table of Contents
Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Material Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Experiment #1: Heat Conduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Experiment #2: Angstrom’s Method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Sample Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Heat Conduction Apparatus
TD-8513
Temperature
Port
Power Input
Ports
Heat/Cool
Switch
Wide Brass Bar
Aluminum Bar
Peltier
Device
Included Equipment Part Number
Heat Conduction Board TD-8513
Heat Sink 624-005
Thumbscrew 617-013
Foam Insulators (qty. 2) 648-09185
Temperature Array Cable 514-09162
Required Equipment Part Number
PASPORT Temperature Array
DC Power Supply PI-9877
4 mm Banana Patch Cords (qty. 2) SE-9750, SE-9751, or similar
1
Temperature Array requires a PASPORT interface; see PASCO catalog or www.pasco.com
2
Or similar power supply capable of supplying at least 5 volts and 1 amp.
1
Heat
Sink
ThermistorsThermistors
PS-2157
2
Narrow Brass Bar
Stainless Steel Bar
Introduction
The PASCO Heat Conduction Apparatus demonstrates the difference in the rate of heat conduction through bars
of different materials and cross-sectional areas. The apparatus has four metal bars: one aluminum, one stainless
steel, and two brass with different cross-sections. One end of each bar is heated or cooled by a Peltier device.
Each bar has two 10 kΩ thermistors embedded about 3 cm from each other. A cable is supplied to connect the
thermistors to a PASPORT Temperature Array (PS-2157) so data can be recorded from all eight sensors simultaneously. Foam insulators cover the bars to minimize heat exchange with the environment.
The embedded thermistors are labeled T1 through T8; these labels correspond to the Temperature Array channels
(1 through 8) on which data is collected. The lines printed on the board indicate the lateral positions of the thermistors within the bars.
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3
Heat Conduction Apparatus Connections
The Heat/Cool switch changes the polarity of the voltage applied to the Peltier device
so that the lower surface of the device either heats or cools the bars. When the switch
is set to Cool, the device pumps heat from the lower surface to the upper surface; the
heat sink helps to dissipate this heat.
Connections
Use the included cable to connect the temperature port of the Heat Conduction Apparatus to the multiport of a PS-2157 Temperature Array. Connect the Temperature
Array to a PASPORT interface. Connect the interface to a computer and start
DataStudio.
1
Connect a PI-9877 DC Power Supply (or similar) to the power input ports of the
1
If your PASPORT interface is an Xplorer GLX,
you can use it without a
computer or DataStudio.
apparatus with the positive terminal of the power supply connected to the red input
port, and the negative terminal connected to the black input port. Set the voltage to
zero.
Safety
The Peltier device and metal bars can be hot. Do not touch them while the appa-
ratus is in use. When applying power to the device, always monitor the temperatures and do not allow them to exceed 80 °C. After use, do not leave the apparatus
unattended until all parts have cooled.
Do not apply more than 15 V or 2 A to the apparatus.
Specifications
Aluminum, stainless steel, and wide brass bar
dimensions
Narrow brass bar dimensions 9 × 0.7 × 0.4 cm
Maximum input voltage 15 VDC
Thermistors Eight embedded 10 kΩ thermistors
9 × 1.2 × 0.4 cm
Material Properties
Brass (360 Alloy) Aluminum (6063-T5) Stainless Steel (304)
3
Density ρ (kg/m
Specific Heat
Conductivity
) 8520 2800 8000
c
(J/kg·K) 385 830 400
k
(W/m·K) 115 150 14
4
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Model No. TD-8513 Experiment #1: Heat Conduction
Experiment #1: Heat Conduction
Equipment Required Model
Heat Conduction Apparatus TD-8513
DC Power Supply PI-9877
Temperature Array
DC Power Supply PI-9877
4 mm Banana Patch Cords (qty. 2) SE-9750, SE-9751, or similar
1
Temperature Array requires a PASPORT interface; see PASCO catalog or www.pasco.com
Set-up
1. On the power supply, turn the Function switch to SET MAX and set the voltage
2. Use two banana patch cords to connect the power supply to the Heat Conduction
1
PS-2157
limit to 8 V; this will prevent accidental overload during the experiment. Turn the
Function switch to constant DC mode ( ).
Apparatus. Connect the positive (+) terminal of the power supply to the red input
jack of the Heat Conduction Apparatus; connect the negative (−) terminal of the
power supply to the black input jack of the Heat Conduction Apparatus.
3. Use the included cable to connect the temperature port of the apparatus to the
multiport of the Temperature Array. Connect the Temperature Array to the
PASPORT interface. Connect the interface to a computer and start DataStudio.
4. Measure the distance between the two thermistors embedded in each bar; their
positions are marked by the white lines on the board.
5. Make a drawing showing the layout of the apparatus including the Peltier device,
the four bars, and the thermistors. Label each thermistor with the following designations:
T1 Wide Brass (far)
T2 Wide Brass (close)
T3 Narrow Brass (close)
T4 Narrow Brass (far)
T5 Aluminum (far)
T6 Aluminum (close)
T7 Stainless (close)
T8 Stainless (far)
A. Heat Conduction Race
Set-up
1. Set the switch to HEAT and place the insulators over the bars.
2. In DataStudio, set the sampling rate of the Temperature Array to 5 Hz. Set up a
graph display to show the temperatures measured by all four “far” thermistors
(T1, T4, T5, and T8).
3. Collect a test run of data to make sure that all four bars are all at room tempera-
ture. Delete the data.
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5
Heat Conduction Apparatus Experiment #1: Heat Conduction
Procedure
1. Set the power supply to 5 V (constant DC) and simultaneously start recording in
DataStudio. Watch the graph of “far” temperatures and allow them to increase for
about 5 minutes. Stop recording.
2. Set the power supply voltage to zero. Remove the insulators to allow the bars to
1
cool.
Analysis
1. Look at the final temperature measured by the “far” thermistor of each bar.
Which material is the best conductor? Which is the worst? Is there a difference
between the two brass bars?
2. Create a graph showing data from both thermistors in the wide brass bar (T1 and
T2). Zoom in on the area of the graph where the temperatures start to increase.
Notice that the temperature at the close thermistor (T2) starts to increase before
the temperature at the far thermistor (T1). Measure this time difference.
3. Calculate the speed of the heat pulse down the brass bar. At this speed, how long
would it take for the pulse to travel the length of the bar?
4. In DataStudio, create a calculation for the temperature differ-
ence (∆T) between the close and far thermistors in the wide
brass bar. Create similar calculations for the other three bars
(be sure to subtract the “far” temperature from the “close”
temperature). Display all four calculations in a graph.
Which bar has the largest ∆T? Which bar has the smallest?
What is the correlation between ∆T and how good a
conductor each material is?
1
To cool the bars faster,
you can set the switch to
COOL and apply 5 volts
for a few minutes; then
wait a few more minutes
with the apparatus
un-powered for the bars
to come to equilibrium.
5. Why does ∆T peak and then decrease? Why does this peak occur at different
times for the four bars?
6. Notice that ∆T in each bar approaches a final equilibrium value. Estimate this
final value for each bar.
7. The rate of heat flow (∆Q/∆t, in joules per second) is given by
Q∆
kA T∆
--------
--------------=
t∆
x
where k is the thermal conductivity of the material, A is the cross-sectional area
of the bar, and x is the distance between the thermistors.
See page 4 for the conductivities of brass, aluminum, and stainless steel. Measure
the dimensions of the bars. Calculate the final heat flow rate in each bar.
8. Which bar has the highest heat flow rate? Is there a correlation between ∆T and
heat flow rate? Why is the heat flow lower in the narrow brass bar than in the
wide one?
Further Study
Repeat the previous experiment with the switch set to COOL. Which direction does
heat flow in this case?
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