PASCO TD-8580A User Manual

Thermal Cavity

TD-8580A

2

TD-8580A

TD-8580A

INPUT POWER

INPUT POW

(10 VOLT MAX)

(10 VOLT MAX)

2

ER

1

1

THERMAL CAVITY

THERMAL CAVITY

Instruction Manual

012-09373B

5

5

6

6

3

3

Included Equipment Part Number

1. Thermal Cavity Assembly TD-8580

2. Cavity Plug 699-122

3. Thermistor Cable PS-2515

4. Base ME-9205

5. Thumbscrews (qty. 2) 617-015

6. Square Nuts (qty. 2) 614-054

7. CD-ROM: Experiment Configuration
Files for DataStudio 576-09345

Required Equipment

Power Supply, 10 V, 1 A CI-6552A, PI-9877, SE- 9720a, SF-9584A, or similar

10 kΩ Thermistor-type Temperature Sensor

or

Resistance Meter

1

See “Suggested Experiments” starting on page 3 for more information about the recommended

equipment and additional equipment required for the experiments described in this manual.

1

CI-6527A, PS-2125, or similar

SE-9786A

4

4

Introduction

The TD-8580A Thermal Cavity can be used in studies of thermal radiation, the Stefan-Boltzmann law, and
reflection and emission of light from different surfaces. The rotatable aluminum cube has a cavity and four dif­ferent surface finishes: black, white, polished, and matte.

When powered by a stand-alone power supply or a Power Amplifier connected to a ScienceWorkshop interface,
the built-in heating element can raise the temperature of the cube to 100 °C. A thermistor embedded in the cube
allows the temperature to be measured with a PASPORT Temperature Sensor, a ScienceWorkshop Thermistor
Sensor, or a resistance meter.

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Thermal Cavity Equipment Setup

With an Infrared Sensor students can examine IR light emission from each of the
cube's surfaces. The addition of a Light Sensor, Rotary Motion Sensor, Aperture
Bracket, and Linear Translator allows students to scan the cavity and generate inten­sity versus position graphs for visible and infrared light.

The apparatus can be mounted on the included rectangular base or on a PASCO Basic
Optics Bench.

Equipment Setup

Mounting on Included Base

1. Place the apparatus upright with the chassis (horizontal support piece)
on the base.

2. Align the outer hole in the chassis with the tapped hole in the base.

3. Insert a thumbscrew through the hole in the chassis and thread it into

the base.

Mounting on an Optics Bench

Mount the apparatus on a Basic Optic Bench for use with a Linear Trans­lator, Aperture Bracket, and other optics equipment.

1. Slide both nuts into the center slot of the optics bench.

2. Align the holes on the chassis of the Thermal Cavity apparatus with

the nuts.

3. Insert the thumbscrews through the holes in the chassis and thread
them loosely into the nuts.

4. Move the apparatus to the desired position on the optics bench.

5. Tighten the thumbscrews.

Base

580

-8

TD

AL C

M

ER

H

T

INPUT POWER
(10 VOLT MAX)

TD-8580A

THERMAL CAVITY

INPUT P
(10 V

A

ITY

AV

R

E

OW

AX)

OLT M

Chassis

Thumbscrew

Thumbscrews

Nuts

Thermistor Sensor Connection

Use the included cable to connect the white pair of jacks labeled
“THERMISTOR SENSOR” to a ScienceWorkshop Thermistor Sensor, a PASPORT
Temperature Sensor, or the temperature port of the Xplorer GLX interface.

You can also use a stand-alone resistance meter or multimeter to read the temperature.
Measure the resistance between the white jacks and use the conversion formula on
page 7 to calculate the temperature.

Power Supply Connection

The Thermal Cavity requires a power supply capable of 10 V and 1 A.

1. Use two banana patch cords to connect the power supply to the red pair of jacks
labeled “INPUT POWER.”

2. Set the voltage as high as 10 V. The cube will reach 100 °C in about 30 minutes.

2

Optics Bench

IMPORTANT: Do not
apply voltage to the white
thermistor jacks.

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Model No. TD-8580A Safety

Safety

CAUTION: The cube can reach 100 °C (212 °F). Do not touch the cube while

the apparatus is in use. Allow the apparatus to cool completely after use before
handling. Do not apply more than 10 V to the apparatus. Always monitor the temper­ature when the apparatus is in use. Do not allow the cube to exceed 100 °C. This
apparatus is intended for use by students only under instructor supervision.

Suggested Experiments

The configuration files called for in these activities can be found on the included
CD-ROM. There are three folders, each containing different versions of the files.
Refer to the table below to find the appropriate files for your equipment.

Equipment Folder containing configuration files

PASPORT PASPORT

ScienceWorkshop (without Power Amplifier) ScienceWorkshop

ScienceWorkshop with Power Amplifier SW with Power Amp

1. Infrared Light Intensity versus Temperature

In this experiment you will measure the IR intensity emitted by the cube as its temper­ature increases.

Required Equipment

Thermal Cavity TD-8580A

For use with PASPORT

Infrared Sensor PS-2148

Temperature Sensor PS-2125 or similar

PASPORT interface or interfaces

Power Supply, 10 V, 1 A PI-9877, SE- 9720a, SF-9584A, or similar

For use with ScienceWorkshop

Infrared Sensor CI-6628

Thermistor Sensor (10 kΩ) CI-6527A

ScienceWorkshop Interface See PASCO catalog or www.pasco.com

Power Amplifier

or

Power Supply, 10 V, 1 A

1

Any PASPORT temperature sensor compatible with thermistor temperature probes can be

used, including the Xplorer GLX’s built-in temperature port.

2

A multiple-port interface or combination of two single-port interfaces is required.

3

The Power Amplifier requires a ScienceWorkshop 750 or 700 interface.

3

2

See PASCO catalog or www.pasco.com

CI-6552A

PI-9877, SE- 9720a, SF-9584A, or similar

1

Setup

1. Mount the Thermal Cavity on the included base. Connect the Thermal Cavity to

the Thermistor Sensor and power supply (but don’t turn it on yet).

2. Connect both sensors to the interface (or interfaces).

1

3. Position the IR sensor on a stand or book so that its sensitive element is 2 cm

from the black surface of the cube.

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1

If you are using a
ScienceWorkshop inter­face, connect the IR sen­sor to Channel A and the
Thermistor sensor to
Channel B; connect the
Power Amplifier (if used)
to Channel C; set the
gain of the IR Sensor
to 1.

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Thermal Cavity Suggested Experiments

4. Open the configuration file IR_vs_Temp.ds.

Procedure

Start with the cube below 40 °C.

1. Click Start.

2. Apply 10 V to the apparatus.

When the cube reaches 40 °C, data recording will automatically begin.

3. After the cube has reached 90 °C, click Stop. (If the cube reaches 100 °C, data
recording will automatically stop.)

4. Turn off power to the apparatus.

Analysis

1. According to your data, how is measured IR intensity related to cube tempera­ture?

2. The Stefan-Boltzmann law states that a surface’s radiant intensity, I, is related to
its absolute temperature, T, by

I εσT

4

=

where ε is the emissivity of the surface, and σ is the Stefan-Boltzmann constant.

The measurement of I made by the IR sensor is proportional to the net power
exchange, P

, between the surface and the sensor. The net power is related to

net

the surface’s absolute temperature, T, and the sensor’s own absolute temperature,

T

, by

0

4

P

net

where k is a constant related to the geometry of the surface and the sensor.

εkσ T

4

T

–()=

0

2

Observe the graphs of I versus T and I versus T4. Does your data appear to
support this relationship?

3. Repeat the experiment with the polished and white surfaces of the cube. How do
the emissivities of the black, polished, and white surfaces compare?

5.670 × 10-8 W/m2·K

σ=

2

The PASPORT IR sen­sor makes a direct mea­surement of T

you can use in your anal­ysis.

, which

0

4

4

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Model No. TD-8580A Suggested Experiments

2. Reflected Visible Light and Emitted Infrared Light

In this experiment you will measure the profile of visible light reflected by the cavity
side of the cube and compare it to the profile of infrared light emitted by it.

Required Equipment

Thermal Cavity TD-8580A

60 cm Optics Bench OS-8541 or part of OS-8515A

Linear Translator OS-8535

Aperture Bracket OS-8534

For use with PASPORT

Light Sensor PS-2106

Infrared Sensor PS-2148

Temperature Sensor PS-2125 or similar

Rotary Motion Sensor PS-2120

PASPORT Extension Cable

PASPORT interface or interfaces

Power Supply, 10 V, 1 A PI-9877, SE- 9720a, SF-9584A, or similar

For use with ScienceWorkshop

Light Sensor CI-6504A

Infrared Sensor CI-6628

Thermistor Sensor (10 kΩ) CI-6527A

Rotary Motion Sensor CI-6538

ScienceWorkshop Interface See PASCO catalog or www.pasco.com

Power Amplifier

or

Power Supply, 10 V, 1 A

1

Any PASPORT temperature sensor compatible with thermistor temperature probes can be

used, including the Xplorer GLX’s built-in temperature port.

2

Not required if the Light and IR sensors will be used with a USB Link.

3

A multiple-port interface or combination of three single-port interfaces is required.

4

The Power Amplifier requires a ScienceWorkshop 750 or 700 interface.

4

2

3

PS-2500

See PASCO catalog or www.pasco.com

CI-6552A

PI-9877, SE- 9720a, SF-9584A, or similar

1

Setup

1. Mount the Thermal Cavity on the Optics Bench.
Connect the thermistor sensor and power supply
(but don’t turn it on yet).

2. Mount the Linear Translator on the optics bench.
Assemble the Linear Translator, Aperture Bracket,
and Light Sensor (refer to the instructions accom­panying the Linear Translator).

3. Arrange the apparatus so that the cavity side of the
cube is about 1.5 cm from the front of the Aperture
Bracket.

4. Turn the wheel on the Aperture Bracket to select
aperture #6.

5. Open the configuration file Reflected_and_Emitted_Light.ds.

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1.5 cm

Optics Bench

Cube

Aperture Bracket

Light Sensor

Linear
Translator

Rotary Motion
Sensor

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Thermal Cavity Suggested Experiments

6. Connect the Light, Thermistor, and Rotary Motion sensors to the interface (or
interfaces).

3

Leave the IR Sensor unconnected for now.

7. In DataStudio, start data monitoring (open the Experiment menu and select Mon­itor Data). The measured cube temperature will appear in the digits display.

8. Turn on the power supply and set the voltage to 10 V. When the cube temperature
reaches about 80 °C, set the voltage to about 7 V. Allow the temperature to stabi­lize between 80 and 100 °C before proceding.

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Procedure

1. Move the Light Sensor to one end of the Linear Translator.

2. Click Stop to stop data monitoring, then Click Start to start data recording.

3. Move the Light Sensor at a slow, steady pace across the Linear Translator to scan

the cavity side of the cube. Click Stop.

Observe the graph of Visible Light Intensity versus Position. If necessary, delete
the data

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and repeat this step to obtain a satisfactory graph.

4. Remove the Light Sensor from the Aperture Bracket and replace it with the IR
Sensor. Connect the IR Sensor to the interface.

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5. Move the IR Sensor to one end of the Linear Translator.

6. Click Start.

7. Move the IR Sensor at a slow, steady pace across the Linear Translator to scan

the cavity side of the cube. Click Stop.

3

If you are using a
ScienceWorkshop inter­face, refer to the
DataStudio configuration
file for sensor gain set­tings and channel asign­ments.

4

If you are using a Power
Amplifier, the power turns
on automatically when­ever data is being moni­tored or recorded. The
temperature is thermo­statically set for 80 °C.
Turn on data monitoring
between data-recording
runs to keep the cube
hot.

5

Open the Experiment
menu and select Delete
Last Run.

6

If you are using a Power
Amplifier and a
ScienceWorkshop inter­face, disconnect the
Light Sensor from Chan­nel A and replace it with
the IR Sensor.

Observe the graph of IR Light Intensity versus Position. If necessary, delete the
data and repeat this step to obtain a satisfactory graph.

8. Turn off power to the Thermal Cavity.

Analysis

1. Compare the graphs of visible and IR light intensity. Which graph displays
reflected light and which displays emitted radiation?

2. When you look at the cavity, does it appear lighter or darker than the surrounding
cube surface? How is the appearance of the cavity represented in the graph of vis­ible light intensity?

3. Allow the cube to cool to room temperature, then remove the cap from the top of
the cube. Does the inner surface of the cavity appear lighter or darker than outer
surface of the cube?

4. In the infrared region of the spectrum, was the cavity brighter or darker than the
cube surface?

5. Compare the emitted radiation of the cavity and the cube surface. Which source
of radiation has the higher emissivity?

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Model No. TD-8580A Sample Data

Sample Data

DataStudio files containing these data can be found on the included CD-ROM.

Infrared Light Intensity versus Temperature

The graphs above show I versus T (above left) and I
versus T
curve fit applied to I versus T is ; note
that the curve intersects the horizontal axis at

T 294 K 21° C==

the sensor.

The graphs of I versus T for the different surfaces of
the cube (right) show that the black and white surfaces
have similar emissivities in the IR region of the spec­trum, and the emissivity of the polished surface is
much lower.

4

(above right) for the black surface. The

IAT

, the approximate temperature of

n

× B+=

Reflected Visible Light and Emitted Infrared Light

These graphs show visible light intensity versus posi­tion (top right) and IR light intensity versus position
(bottom right) at 92 °C. In the visible region of the
spectrum, the cavity is darker than the surrounding
cube surface; in the IR region the cavity is brighter.

Resistance to Temperature Conversion

To find the temperature (T) measured in kelvin based on the resistance (R) of the
embedded thermistor measured in kΩ, use the formula:

1

--- AB

T

®

R



------

ln⋅ C



10

2

R



------

ln

⋅ D



10

⋅++ +=

3

R



------

ln



10

7

Thermal Cavity Specifications

where , , , and

A 3.35 10

D 8.37 10

×=

3–

×= B 2.56 104–×= C 2.38 106–×=

8–

.

Specifications

Power requirement 10 V, 1 A

Maximum input voltage 10 V

Heating resistor 10 Ω, 10 W max
Thermistor 10 kΩ at 25 °C

Maximum temperature 100 °C

Cube Aluminum, 3 × 3 × 3 cm

Technical Support

For assistance with any PASCO product, contact PASCO at:

Address: PASCO scientific

10101 Foothills Blvd.
Roseville, CA 95747-7100

Phone: [phone] (worldwide)

800-772-8700 (U.S.)

Fax: [phone]

Web: www.pasco.com

Email: [e-mail]

Limited Warranty

For a description of the product warranty, see the PASCO catalog.

Copyright

The PASCO scientific 012-09373B Thermal Cavity Instruction Manual is copyrighted with all rights reserved. Permission is granted to
non-profit educational institutions for reproduction of any part of this manual, providing the reproductions are used only in their labora­tories and classrooms, and are not sold for profit. Reproduction under any other circumstances, without the written consent of PASC O
scientific, is prohibited.

Trademarks

PASCO, PASCO scientific, DataStudio, PASPORT, ScienceWorkshop, Xplorer, and Xplorer GLX are trademarks or registered trade­marks of PASCO scientific, in the United States and/or in other countries. All other brands, products, or service names are or may be
trademarks or service marks of, and are used to identify, products or services of, their respective owners. For more information visit
www.pasco.com/legal.

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