PASCO SF-8563 User Manual

Instruction Sheet
for the PASCO
Model SF-8563

Molecular Motion Demonstrator

012-03407B

12/92
$1.00

SF-8563 Molecular

Motion Demonstrator

PI-9587A Function Generator/Amplifier

or PI-9598 Student Wave Generator

Wave Driver

(WA-9753 or SF-9324)

Introduction

The PASCO Model SF-8563 Molecular Motion
Demonstrator is used to model the behavior of gas
molecules in a closed container. The molecules of the
gas are represented by fifty-one steel ball bearings. In
the kinetic theory of gasses, as a gas is heated, the
random kinetic energy of the molecules increases,
increasing the pressure of the gas on the sides of the
container. In this demonstration, kinetic energy is
imparted to the ball bearings by a vibrating plunger
which fits into a slot in the bottom of the container.

Operation

➤ Note:

The SF-8563 Molecular Motion Demonstrator is
designed to be used with a wave driver. The
wave driver must be powered by a function
generator capable of delivering at least 0.5 A of
current into an 8 Ω load. (We recommend the
PASCO Model PI-9587A Function Generator/
Amplifier or PI-9598 Student Wave Generator.)

➀ Set up the Molecular Motion Demonstrator as

shown below, but leave the pressure plate out for
now.

The banana plug connector on the plunger mates
with the drive arm of the wave driver. The base of
the ball bearing container then mounts to the top of
the wave driver using the thumbscrews to hold it in
place. The plunger slides through the slot in the

Pressure

plate

Container with

bearings and base

Plunger

Connect to

PI-9587A

or PI-9598

Wave driver

10101 Foothills Blvd. • P.O. Box 619011 • Roseville, CA 95678-9011 USA

Phone [phone] • FAX [phone] • TWX 910-383-2040

better

ways to

teach physics

012-03407B

bottom of the glass-walled container.

➁ Connect the function generator to the wave driver.

Start with minimum amplitude and low frequency
(a few Hertz) vibrations. Vary the amplitude and/or
frequency of the vibrations and observe the effects
on the ball bearings. As the energy transfer to the
ball bearings increases, the motion of the bearings
increases. Your students can get a sense for how a
solid substance, when heated, goes through phase
transformations, first to a liquid state, then to a gas­eous state. They can also note how the bearing den­sity varies with altitude, much as the density of at­mosphere varies with altitude.

➂ Now slide the pressure plate into the slot in the top

of the container as shown.
Vary the amplitude and/or
frequency of the vibrations.
Your students can see how
the pressure exerted by the
bearings increases with in­creasing kinetic energy.
They can also see how in­creasing the kinetic energy
of the bearings (heating up in
a gas) can cause work to be
performed on the pressure plate, as heating a gas
can cause a piston to rise in a heat engine.

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.

➃

You can use an overhead projector to help your stu­dents see the demonstration more easily. Just tilt
the Molecular Motion Demonstrator over the pro­jector as shown in the illustration.

Overhead Projector

2