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M o d e l N o . T D - 8 5 1 3
E x p e r im e n t # 2 : An g s t r o m ’s M e t h o d
9
Experiment #2: Angstrom’s Method
Set up
1.
On the power supply, turn the Function switch to SET MAX and set the voltage
limit to 8 V; this will prevent accidental overload during the experiment. Turn the
Function switch to constant DC mode (
).
2.
Use two banana patch cords to connect the power supply to the Heat Conduction
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.
On the Heat Conduction Apparatus set the switch to COOL.
4.
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.
5.
Measure the distance between the two thermistors embedded in each bar; their
positions are marked by the white lines on the board.
6.
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 des-
ignations:
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)
Theory
In this experiment, you will measure the thermal conductivity of the metal bars using
Angstrom’s method. A periodic wave travels down the bar and the resulting tempera-
ture wave is measured at two points using thermistors. The thermal diffusivity,
α
, can
determined by measuring the amplitude of the temperature wave at the close ther-
mistor (A
c
) and the amplitude at the far thermistor (A
f
) as well as the relative phase
(
φ
) between these two waves.
Equipment Required
Model
Heat Conduction Apparatus
TD-8513
DC Power Supply
PI-9877
Temperature Array
1
1
Temperature Array requires a PASPORT interface; see PASCO catalog or www.pasco.com
PS-2157
DC Power Supply
PI-9877
4 mm Banana Patch Cords (qty. 2)
SE-9750, SE-9751, or similar
