PASCO TD-8552 User Manual

Includes

Teacher's Notes

and

Typical

Experiment Results

Instruction Manual and
Experiment Guide for
the PASCO scientific
Model TD-8552

ELECTRICAL
EQUIVALENT

OF HEAT

012-02833D

5/94

ELECTRICAL

ENERGY

 1987 PASCO scientific $5.00

HEAT

012-02833D Electrical Equivalent of Heat

T able of Contents

Section Page

Copyright and Warranty ..................................................................................ii

Equipment Return............................................................................................ii

Introduction .....................................................................................................1

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

Maintenace.......................................................................................................2

Experiments:

Experiment 1: The Electrical Equivalent of Heat......................................3

Experiment 2: Efficiency of an Incandescent Lamp .................................5

Teacher's Guide ............................................................................................... 7

i

Electrical Equivalent of Heat 012-02833D

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-8552 Electrical
Equivalent of Heat 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

012-02833D Electrical Equivalent of Heat

Introduction

The PASCO Model TD-8552 Electrical Equivalent of
Heat Apparatus provides an experimental determina­tion of the quantitative relationship between electrical
energy and heat. Conversely, if the electrical equiva­lent of heat is accepted as a given, this apparatus can
provide a convincing demonstration of the conserva­tion of energy. With either approach, the experiment
is easily extended to determine the energy efficiency
of an incandescent lamp.

Instructions for two experiments, along with student
worksheets, are on pages 3-6. In Experiment 1, the Electri­cal Equivalent of Heat is experimentally determined. An
incandescent lamp is immersed in a known quantity of water
and a few drops of India ink are added to the water so it is
opaque to visible light. The temperature of the water is
measured. The lamp is then illuminated with a fixed current

Equipment

Your Model 8552 Electrical Equivalent of Heat
apparatus includes the items shown in Figure 1: a
transparent Electrical Equivalent of Heat Jar (EEH Jar)
with a built-in 35 Watt incandescent lamp, two
styrofoam Calorimeters, and a bottle of India ink.

and voltage for a measured time interval, so the electrical
energy into the lamp can be calculated. By monitoring the
temperature of the water, the heat produced by the lamp can
also be calculated. The ratio between the electrical energy
that flows into the lamp and the heat produced by the lamp
determines the electrical equivalent of heat.

In Experiment 2, the efficiency of the incandescent lamp is
measured. The details are similar to Experiment 1, but no
india ink is added to the water. Without the ink, the thermal
energy and infrared radiation from the lamp are absorbed
into the water, but the visible light escapes. To determine
the amount of energy that was released as light, the heat
transferred into the water is subtracted from the total
electrical energy that flowed into the lamp . The ratio
between the light energy and the electrical energy gives the
efficiency of the bulb.

➁ A digital Volt-Ammeter (a separate voltmeter and

ammeter are best) for measuring the power input to
the lamp. (Such as PASCO Model SE-9589.)

➂ A clock or stopwatch to determine the electrical en-

ergy that flows into the lamp (energy = power x
time).

Figure 1 Equipment

Additional Equipment Needed:

In addition to the equipment included with your
Electrical Equivalent of Heat apparatus, you will need
the following items to perform the experiments in this
manual:

➀ A regulated power supply capable of delivering up

to 3 A at 12 V. (Such as PASCO Model SF-9584.)

➃ A thermometer, or PASCO's TD-8559 Thermistor

Probe.*

➄ A balance for accurately determining the mass of

the water heated by the bulb.
(* A digital ohmmeter (SE-9589) is recom-

mended for use with the Thermistor Probe.)

➤ IMPORTANT: When using the Electrical
Equivalent of Heat Apparatus, always observe
the following precautions:

➀ Do not fill the water beyond the line indicated

on the EEH Jar. Filling beyond this level can
significantly reduce the life of the lamp.

➁ Illuminate the lamp only when it is immersed

in water.

➂ Never power the incandescent lamp at a

voltage in excess of 13 V.

1