PASCO TD-8592 User manual

012-08375A
SMALL PISTON HEAT
ENGINE APPARATUS
Instruction Manual and
Experiment Guide for the
PASCO scientific
Model TD-8592

The exclamation point within an equilateral
triangle is intended to alert the user of the
presence of important operating and mainte-
nance (servicing) instructions in the literature
accompanying the appliance.

i
012-08375A Small Piston Heat Engine
Table of Contents
Section Page
Copyright, Warranty, and Equipment Return ....................................................ii
Introduction ...................................................................................................... 1
Equipment ........................................................................................................ 1
Experiments
1) Operation of a Heat Engine........................................................................ 3
2) Charles’ Law ............................................................................................. 5
3) Boyle’s Law .............................................................................................. 7
4) Combined Gas Law (Gay-Lussac’s) .......................................................... 9
5) The Mass Lifter Heat Engine ................................................................. 11–18
Technical Support ................................................................................... Back Cover

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Small Piston Heat Engine 012-08375A
Equipment Return
If the product requires return 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.
➤➤
➤➤
➤ NOTE: NO EQUIPMENT WILL BE
ACCEPTED FOR RETURN WITHOUT AN
AUTHORIZATION FROM PASCO.
When returning equipment for repair, the units must
be properly packed. Carriers will not accept respon-
sibility for damage caused by improper packing. To
be certain the unit will not be damaged in shipment,
observe the following rules:
➀The packing carton must be strong enough for the item
shipped.
➁Make certain there are at least two inches of packing
material between any point on the apparatus and the
inside walls of the carton.
➂Make 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: [email protected]
web: www.pasco.com
Credits
Editor: Sunny Bishop
Copyright Notice
The PASCO scientific 012-08375A Small Pistion Heat
Engine manual is copyrighted and all rights reserved.
However, permission is granted to non-profit educational
institutions for reproduction of any part of the 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 the 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 workman-
ship. The 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.
Copyright, Warranty, and Equipment Return
Please—Feel free to duplicate this manual
subject to the copyright restrictions below.

012-08375A Small Piston Heat Engine
1
Tubing for connecting
chamber to cylinder
one-way
check valves
Air chamber for
immersing in hot
or cold water
Note: Use only non-caustic/non-toxic
gases such as air or helium.
pressure port mating connectors
The PASCO TD-8592 Small Piston Heat Engine is used
for quantitative experiments involving the Ideal Gas Law
(as described below) and for investigations of a working
heat engine. The equipment allows the amount of work
done by thermal energy to be measured.
Introduction
The heart of this apparatus is a nearly friction-free piston/
cylinder system. The graphite piston fits snugly into a
precision-ground Pyrex cylinder so that the system
produces almost friction-free motion and negligible
leakage.
The apparatus includes the following equipment:
•Baseapparatus(Figure1)
- piston diameter: 15.9 mm ± 0.1
- mass of piston and platform: 15.9 g ± .06
•Airchamber(Figure2)
•Threehoseconfigurations:onewithone-waycheck
valves and one with a clamp (Figure 2), and one
plain piece of tubing (not shown)
•Oneeach,one-holedandtwo-holedrubberstopper
Figure 2. Air chamber and tubing
The Small Piston Heat Engine is designed with two
pressure ports with quick-connect fittings for connecting
to the air chamber tubing.
The apparatus can be connected to a Low Pressure Sensor
for use with PASCO computer interfaces.
Always release the tubing clamps prior to
storage to avoid permanently deforming the
tubing.
Do not apply lubricant to the piston or
cylinder.
Maximum Pressure: 345 kPa.
Precision-bore
pyrex cylinder
inside a protective
plastic shield
Graphite piston
with mm scale for
measuring piston
displacement
Pressure port
mating
connectors
Figure 1. Base apparatus with piston
Piston-holding
thumbscrew
Do not immerse the base apparatus in
liquid.
Equipment
clamp
Mass platform for
adding a load to
do work
experiments

2
Small Piston Heat Engine 012-08375A
Notes:

012-08375A Small Piston Heat Engine
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Experiment 1: Operation of a Heat Engine
➀Using the one-holed stopper, connect the tubing
with the one-way valves to the air chamber and
to a connecting port on the base assembly.
➁Close the shut-off valve on the tubing from the
unused port.
➂Set a mass of 50 to 100 g on the mass platform.
➀Move the air chamber from an ice water bath to a
hot water bath. You will note that the air in the
chamber quickly expands through the tubing and
moves the piston up. Note also that the one-way
check valve in the tubing connecting the base
apparatus and the air chamber permits air to enter
the cylinder, while the other one-way checkvalve
prevents air from leaving through the branched
tube.
Equipment Setup
➤Note: Use a maximum mass of 100 grams in
the experiment. A larger mass will cause the
valve seals to leak.
Procedure
Figure 1.1. Setup for the Heat Engine
Close the shut-off
valve on the
tubing from the
unused port.
direction of
air flow
one-way check
valves
➁Move the air chamber back to the cold bath and note that external air is sucked into the air chamber through the
one-way valve located at the end of the branched tube. Note also that the one-way valve in the connecting
tube prevents the air from escaping from the piston, so the height of the piston remains the same.
➂Repeat steps 1 and 2 until the mass has been completely lifted. The greater the temperature differential be-
tween the hot and cold water baths, the greater the lift achieved through each cycle through them.
EquipmentRequired:
•SmallPistonHeatEngine
•Mass,50–100gmass
•Containerofhotwater
•Containeroficewater
mass
air chamber
Note: For a more detailed, quantitative investiagtion of the heat engine operation, see Experiment 5 (page 11).

4
Small Piston Heat Engine 012-08375A
Notes:

012-08375A Small Piston Heat Engine
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Experiment 2: Charles’ Law
Charles’ law states that at a constant pressure, the volume of a fixed mass or quantity of gas varies
directly with the absolute temperature:
V= cT (at constant pressure, P, where temperature, T, is
expressed in degrees Kelvin)
➀Using the one-holed stopper and plain tubing, connect the base apparatus and the air chamber.
➁Close the shut-off valve on the tubing from the unused port.
➂Turn the base apparatus on its side. (In this position, the force acting on the apparatus is the
atmospheric pressure and is equal throughout the range of operation of the piston.)
Theory
Setup
Procedure
➀Place the air chamber in a container of hot water. After the chamber equilibrates to the
temperature, record the temperature and the height of the piston.
➁Add ice to the container and record the temperature and pressure at regular time intervals.
➂Calculate the gas volumes at the various piston positions you measured and make a graph of plots of tempera-
ture versus volume. (Hint: The diameter of the piston is 15.9± 0.1 mm.)
EquipmentRequired:
•SmallPistonHeatEngine
•Thermometer
•Containerofhotwater
•Ice
Do not allow the tip of the
thermometer to touch the
bottom of the container.
Add ice.
Close the shut-off valve on
the tubing from the unused
port.
Figure 2.1: Experiment setup

6
Small Piston Heat Engine 012-08375A
Notes:

012-08375A Small Piston Heat Engine
7
Experiment 3: Boyle’s Law
Theory
Boyle’s law states that the product of the volume of a gas times its pressure is a constant at a fixed
temperature:
P= a
V
➀With the platform raised to its uppermost
position, connect the Pressure Sensor to a port on
the base apparatus with a short piece of tubing
(Figure 3.1).
➁Close the shut-off valve on the tubing from the
unused port.
➂Connect the Pressure Sensor to the computer
interface and set up DataStudio to record pres-
sure. Be sure that you set up the keyboard
sampling option so you can enter height data by
hand. (See “Manual Sampling” or “Keyboard
Sampling” in the DataStudio online help.)
Procedure
➀Record the height of the piston and the pressure
when the platform is raised to its highest position.
➁Press the platform down to a series of levels and
record the height and pressure at each level.
➂Convert the height measurements to gas volume
measurements. (Hint: The diameter of the piston
is 32.5 mm.)
➃Prepare a graph of pressure versus volume.
Therefore, at a fixed temperature, the pressure will be inversely related to the volume, and the
relationship will be linear:
*For details on setting up and operating the Pressure Sensor with DataStudio software, please
consult the instruction sheet for the Pressure Sensor and the DataStudio online help.
PV = a
Setup
➤Note: At pressures greater than 120 kPa, the relationship between pressure and volume may
not be linear because of air leakage from the valves and ports at higher pressures.
Figure 3.1. Experiment setup
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To computer interface
Close the shut-off
valve on the tubing
from the unused
port.
Pressure Sensor
EquipmentRequired:
•SmallPistonHeatEngine
•PressureSensor(CI-6532A)
•Science Workshop computer interface*
• DataStudio software

8
Small Piston Heat Engine 012-08375A
Notes:

012-08375A Small Piston Heat Engine
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Tighten the
piston-holding
thumb screw.
hot plate
Temperature
Sensor
Gas Law Apparatus
to
computer
interface
EquipmentRequired:
•SmallPistonHeatEngine
•PressureSensor(CI-6532)
•Science
Workshop®computer interface*
•TemperatureSensor(CI-6505)
•Hotplate
•Beakerwithwater
•Ice
Experiment 4: Combined Gas Law (Gay-Lussac’s )
*For details on setting up and operating the Pressure Sensor and Temperature Sensor with DataStudio
software, please see the instruction sheets for the Pressure and Temperature Sensors and the
DataStudio online help.
Theory
Charles’ law states that the volume,V, is proportional to the temperature, T. Boyle’s law states that the volume,
V, is proportional to the pressure, P, where pressure=1/P. Combining these, we have:
V=aT
P
The combined gas law predicts that for a given mass of gas, if Vis held constant, Pis proportional
to T.
➀Secure the piston just above its lowest
position by tightening the thumb screw.
➁Connect the Pressure Sensor to a port on the
base apparatus with a short piece of tubing.
➂Connect the air chamber fitted with the
two-holed stopper to the other port of the base
apparatus with a piece of tubing.
➃Insert the Temperature Sensor into the other
hole of the rubber stopper.
Setup
Figure 4.1. Experiment Setup
Pressure
Sensor
To computer interface
Use a silicon lubricant on the end of
the Temperature Probe to aid insertion
and to prevent damage to the probe.
➤Note: You can substitute a thermometer in the water container for the Temperature Sensor.
Be sure to keep the tip of the thermometer from touching the bottom of the container.
➄Connect the Pressure Sensor and Temperature
Sensor to the computer interface, and set up the
DataStudio software program to graph tempera-
ture versus pressure.
•DataStudiosoftware

10
Small Piston Heat Engine 012-08375A
➅Place the air chamber in the Pyrex container and turn on the hot plate.
Procedure
➀Record the temperature and pressure as the water heats.
➁Display a graph of temperature versus pressure in DataStudio software.
Notes:

012-08375A Small Piston Heat Engine
11
Experiment 5: The Mass Lifter Heat Engine1
1Priscilla W. Laws, et al. Workshop Physics Activity Guide, 1996 by John Wiley & Sons, Inc.
Reprinted by permission of John Wiley & Sons, Inc.
Your working group has been approached by the Newton Apple Company about testing a heat engine that lifts
apples that vary in mass from 50 g to 100 g from a processing conveyer belt to the packing conveyer belt that is
10 cm higher. The engine you are to experiment with is a "real" thermal engine that can be taken through a
four-stage expansion and compression cycle and that can do useful mechanical work by lifting small masses
from one height to another. In this experiment, we would like you to verify experimentally that the useful
mechanical work done in lifting a mass, m, through a vertical distance, y, is equal to the net thermodynamic
work done during a cycle as determined by finding the enclosed area on a P-V diagram. Essentially you are
comparing useful mechanical “magy” work (which we hope you believe in and understand from earlier studies)
with the accounting of work in an engine cycle as a function of pressure and volume changes given by the
expression:
Although you can prove mathematically that this relationship holds, the experimental verification will allow you
to become familiar with the operation of a real heat engine.
Wnet = PdV
Optional:
•Acomputer-basedlaboratorysystemwithbarometersensor
EquipmentRequired:
•SmallPistonHeatEngine(1)
•Beakers(2),1000ml(touseasreservoirs)
•Ruler(1)
•Barometerpressuregauge(1)
•Calipers(1set)
•Massset,20g,50g,100g,200g
•Hotplate(1)
•Vattocatchwaterspills(1)
Figure 5.1. Doing useful mechanical
work by lifting a mass, m , through a
height, y .
Figure 5.2 Doing thermodynamic
work in a heat engine cycle.
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The Small Piston Heat Engine is ideal for use in the calculus-based experiment 18.10 of the Workshop
Physics Activity Guide. Following is a slightly modified reprint of the experiment:

12
Small Piston Heat Engine 012-08375A
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If the temperature of the air trapped inside the cylinder, hose, and can is increased, then its volume will
increase, causing the platform to rise. Thus, you can increase the volume of the trapped air by moving
the can from the cold to the hot reservoir. Then, when the apple has been raised through a distance y, it
can be removed from the platform. The platform should then rise a bit more as the pressure on the
cylinder of gas decreases a bit. Finally, the volume of the gas will decrease when the air chamber is
returned to the cold reservoir. This causes the piston to descend to its original position once again. The
various stages of the mass lifter cycle are shown in Figure 5.3.
Before taking data on the pressure, air volume, and height of lift with the heat engine, you should set it
up and run it through a few cycles to get used to its operation. A good way to start is to fill one container
with room temperature water and another with hot tap water or preheated water at about 60–70°C. The
engine cycle is much easier to describe if you begin with the piston resting above the bottom of the
cylinder. Thus, we suggest you raise the piston a few centimeters before inserting the rubber stopper
firmly in the can. Also, air does leak out of the cylinder slowly. If a large mass is being lifted, the
leakage rate increases, so we suggest that you limit the added mass to something between 50 g and 100
g. After observing a few engine cycles, you should be able to describe each of the points a, b, c, and d
Figure 5.3. A schematic diagram of the incredible mass lifter heat engine
Close the shut-off valve
on the tubing from the
unused port.
The Incredible Mass Lifter Engine
The heat engine consists of a hollow cylinder with a graphite piston that can move along the axis of the cylinder
with very little friction. The piston has a platform attached to it for lifting masses. A short length of flexible
tubing attaches the cylinder to an air chamber (consisting of a small can sealed with a rubber stopper that can be
placed alternately in the cold reservoir and the hot reservoir. A diagram of this mass lifter is shown in Figure
5.2.

012-08375A Small Piston Heat Engine
13
Figure 5.4. A simplified diagram of the mass lifter heat engine at different stages of its cycle
of a cycle carefully, indicating which of the transitions between points are approximately adia-
batic and which are isobaric. You can observe changes in the volume of the gas directly and you
can predict how the pressure exerted on the gas by its surroundings ought to change from point to
point by using the definition of pressure as force per unit area.
5.1 Activity: Description of the Engine Cycle
a. Predicted transition a ➔ b: Close the system to outside air but leave the can in the cold reservoir.
Make sure the rubber stopper is firmly in place in the can. What should happen to the height of
the platform when you add a mass? Explain the basis of your prediction.
b.Observedtransitiona ➔ b: What happens when you add the mass to the platform? Is this what
you predicted?
c.Predictedtransitionb
➔ c: What do you expect to happen when you place the can in the hot
reservoir ?
d. Observed transition b
➔ c: Place the can in the hot reservoir and describe what happens to
the platform with the added mass on it. Is this what you predicted? (This is the engine
power stroke!)
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14
Small Piston Heat Engine 012-08375A
e.Predictedtransitionc ➔ d: Continue to hold the can in the hot reservoir and predict what will happen
if the added mass that is now lifted is removed from the platform and moved onto an upper con-
veyor belt. Explain the reasons for your prediction.
f.Observedtransitionc
➔ d: Remove the added mass and describe what actually happens. Is this what
you predicted?
g.Predictedtransitiond
➔ a: What do you predict will happen if you now place the can back in the
cold reservoir? Explain the reasons for your prediction.
h.Observedtransitiond
➔ a: Now it's time to complete the cycle by cooling the system down to its
original temperature for a minute or two before placing a new mass to be lifted on it. Place the can
in the cold reservoir and describe what actually happens to the volume of the trapped air. In
particular, how does the volume of the gas actually compare to the original volume of the trapped
air at point a at the beginning of the cycle? Is it the same or has some of the air leaked out?
i.Theoretically,thepressureofthegasshouldbethesameonceyoucoolthesystembacktoits
original temperature. Why?
Determining Pressures and Volumes for a Cycle
To calculate the thermodynamic work done during a cycle of this engine, you will need to be able to
plot a P-V diagram for the engine based on determinations of the volumes and pressures of the
trapped air in the cylinder, tubing, and can at the points a, b, c, and din the cycle.
5.2 Activity: Volume and Pressure Equations
a.Whatistheequationforthevolumeofacylinderthathasaninnerdiameterofd and a length L?
b.Usethedefinitionofpressuretoderivetheequationforthepressureonagasbeingcontainedbya
vertical piston of diameter d if the total mass on the piston including its own mass and any added
mass is denoted as M. Hints: (1) What is the definition of pressure? (2) What is the equation
needed to calculate the gravitational force on a mass, M, close to the surface of the Earth? (3) Don't
forget to add in the atmospheric pressure, Patm, acting on the piston and hence the gas at sea level.
Now that you have derived the basic equations you need, you should be able to take your engine
through another cycle and make the measurements necessary for calculating both the volume and
the pressure of the air and determining a P-V diagram for your heat engine. Instead of calculating
the pressures, if you have the optional equipment available, you might want to measure the pres-
sures with a barometer or a barometer sensor attached to a computer-based laboratory system.

012-08375A Small Piston Heat Engine
15
5.3 Activity: Determining Volume and Pressure
a. Take any measurements needed to determine the volume and pressure of air in the system at
all four points in the engine cycle. You should do this rapidly to avoid air leakages around the
piston and summarize the measurements with units in the space below.
b. Next you can use your measurements to calculate the pressure and volume of the system at point
a. Show your equations and calculations in the space below and summarize your results with
units. Don't forget to take the volume of the air in the tubing and can into account!
Pa=
Va=
c.Usethemeasurementsatpointbto calculate the total volume and pressure of the air in the
system at that point in the cycle. Show your equations and calculations in the space below and
summarize your results with units.
Pb=
Vb=
d.Whatistheheight,y, through which the added mass is lifted in the transition from bto c?
e.Usethemeasurementsatpointcto calculate the total volume and pressure of the air in the
system at that point in the cycle. Show your equations and calculations in the following
space and summarize your results with units.
Pc=
Vc=
f.Removetheaddedmassandmakeanymeasurementsneededtocalculatethevolumeand
pressure of air in the system at point d in the cycle. Show your equations and calculations in the
space below and summarize your results with units.