PASCO TD-8558A User Manual

Includes

Teacher's Notes

and

Typical

Experiment Results

THERMAL EXPANSION

Instruction Manual and
Experiment Guide for
the PASCO scientific
Model TD-8558A

APPARATUS

012-04394C

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© 1990 PASCO scientific $2.00

012-04394C Thermal Expansion Apparatus

T able of Contents

Section Page

Copyright, Warranty and Equipment Return.................................................. ii

INTRODUCTION:

Equipment..................................................................................................1

Additional Equipment Required................................................................1

Notes on Temperature Measurement.........................................................1

Accepted Values for Coefficient of Thermal Expansion...........................2

Changing Tubes.........................................................................................2

Replacement Parts .....................................................................................2

EXPERIMENT:

Measuring the Coefficient of Linear Expansion for Copper, Steel, and
Aluminum:

Introduction .........................................................................................3

Procedure .............................................................................................3

Data and Calculations..........................................................................4

Questions .............................................................................................5

Thermistor Conversion Table:.............................................................5

Teacher’s Guide...............................................................................................1

Technical Support............................................................................................3

i

Thermal Expansion Apparatus 012-04394C

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-8558A Thermal
Expansion Apparatus manual is copyrighted and all
rights reserved. However, permission is granted to
non-profit educational institutions for reproduction of
any part of this 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 this 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. This 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.

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

packing 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: [phone]
FAX: [phone]
email: [e-mail]
web: www.pasco.com

ii

012-04394C Thermal Expansion Apparatus

Introduction

Introduction

The PASCO Model TD-8558A Thermal Expansion
Apparatus provides easy and accurate measurements
of the coefficient of linear expansion for steel, copper,
and aluminum.

To make the measurement, the steel, copper, or
aluminum tube is placed on the expansion base. The
length of the tube is measured at room temperature,
then steam is passed through it. The expansion of the
metal is measured with 0.01 mm resolution using the
built-in dial-gauge. Temperatures are measured to
within 0.5 °C using a thermistor attached to the center
of the tube. If you wish to investigate the expansion of
the metals at additional temperatures, hot or cold water
can be passed through the tubes.

Complete step by step instructions and a data sheet for
results are provided on the following pages.

Equipment

Your TD-8558A Thermal Expansion Apparatus
includes:

• A 70 cm long expansion base with a built-in dial
gauge and thermistor.

➤ NOTE: The dial gauge can be removed or
repositioned by loosening the screw on the dial
gauge mounting block.

• Three metal tubes — steel, copper (99.5% Cu,

0.5% Te), and aluminum (98.9% Al, 0.7% Mg,

0.4% Si): 5/8-inch outside diameter with 1/4­inch outside diameter connectors. Each tube has a
thumbscrew for attaching the thermistor lug.

• A foam insulator to avoid heat loss at the ther­mistor connection point.

Additional Equipment Required

In addition to the TD-8558A Thermal Expansion
Apparatus, the following items are needed to perform
the experiment:

➀ A source of steam or hot water, such as the PASCO

Model TD-8556 Steam Generator.

➁ A digital ohmmeter such as PASCO Model SE-

9589 to measure the thermistor resistance. Leads
should have banana plug connectors, such as
PASCO Model SE-9750 or SE-9751 Patch Cords.

➂ A small object to raise the end of the expansion

base approximately 2-inches and a container to
catch the water as it drains out of the tube.

If additional data points are desired you will also

➃

need: a source of hot or cold water.

Notes on Temperature Measurement

A thermistor's resistance varies reliably with tempera­ture. The resistance can be measured with an ohmme­ter, and converted to a temperature measurement using
the conversion table provided on the expansion base
and also on the back page of this manual. Although
the relationship between temperature and resistance is
not linear, a linear approximation can be accurately
used to interpolate between table data points with an
accuracy of approximately ±0.2 °C.

The thermistor used to measure the tube temperature is
embedded in the thermistor lug. Once thermal equilib­rium has been reached, the heat is highly uniform
along the length of the tube. The foam insulator is
used to inhibit heat loss through the thermistor lug so
the lug temperature closely follows the tube tempera­ture. The insulator does not have any appreciable
effect on the local temperature of the tube itself.

• Thermoplastic elastometer tubing with 1/4" I.D.

1