Ondas Gerti a Naz

7/24/2019 Ondas Gerti a Naz

1/40

Instruction Sheet

for the PASCO

Model WA-9771

012-05722A

5/95

$1.00

better

teach science

ways to

Phone (916) 786-3800 FAX (916) 786-8905 email: [email protected]

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

PROJECTION SCREEN ACCESSORY KIT

Introduction

The PASCO Model WA-9771 Projection Screen Acces-

sory is designed to be used with the PASCO WA-9775

Ripple Tank System to display wave patterns in large

classrooms and lecture halls. The accessory includes an

acrylic mirror, a white translucent screen and four pre-cutVelcro strips.

Equipment

The PASCO Model WA-9771 Projection Screen

Accessory includes the following:

acrylic mirror (approximately 53 X 40cm)

acrylic screen (approximately 48 X 37cm)

four Velcro loop strips

(approximately 8.5 X 5cm)

Setup Procedure

Assemble the WA-9773 Ripple Tank as per the in-

structions in the Ripple Tank manual.

Turn the Ripple Tank so the front is facing you (label

side toward you).

Peel the protective backing from a Velcro loop strip

and affix it to the top of the right front leg by placing

the center of the strip on the front of the leg and wrap-

ping the ends toward the back of the leg as shown in

Figure 1. Affix a second strip to the bottom of the

right front leg. Repeat this procedure for the left frontleg.

Peel the protective plastic film from the mirror and

screen.

Install the mirror by sliding the mirror flange into the

back of the Ripple Tank between the frame and the

glass. See Figure 2.

Connect the viewing screen to the Ripple Tank by

aligning the Velcro hook on the screen with the

Velcro loop on the legs and pressing firmly together.

1995 PASCO scientific

This instruction sheet written/edited by:

Mary Ellen Niedzielski

Velcro is a registered trademark


2/40

2

Projection Screen Accessory Kit 012-05722A

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 workman-

ship. 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 ship-

ment will not be covered by the warranty.) Shippingcosts for returning the equipment, after repair, will be

paid by PASCO scientific.

Equipment Return

Should this product have to be returned to PASCO scien-

tific, for whatever reason, notify PASCO scientific by

letter or phone BEFORE returning the product. Upon

notification, the return authorization and shipping instruc-

tions will be promptly issued.

NOTE:

NO EQUIPMENT WILL BE ACCEPTED FOR

RETURN WITHOUT AN AUTHORIZATION.

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 fol-

lowing rules:

The carton must be strong enough for the item

shipped.

Make certain there is at least two inches of packing

material between any point on the apparatus and the

inside walls of the carton.

Make certain that the packing material can not shift in

the box, or become compressed, thus letting the instru-

ment come in contact with the edge of the box.

WA-97

73

RIPPLE

TANK

FRAGILE

- GLASS

DRAINT

ANKAFT

ERUSE

acrylicmirror

Velcrostrip (4)

acrylic

screen

WA-9773Ripple Tank

Figure 1: Projection Screen Accessory Assembly

acrylic mirror

glass andgasket ofripple tank

ripple tank leg

Figure 2: Location of Mirror Flange

ripple tankframe


3/40

Instruction Sheet

for the PASCO

Model WA-9773

012-05837A

5/95

$1.00

better

teach science

ways to

Phone (916) 786-3800 FAX (916) 786-8905 email: [email protected]

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

RIPPLE TANK

long straightreflector (2)

mini straightreflector

curvedreflector

triangularrefractor

convexrefractor

concaverefractor

clear plasticrule

rubberstopper

tank frame

tank legs (4)

short straightreflector

Introduction

The WA-9773 Ripple Tank is the core of the Basic

Ripple Tank System and allows the user to create wave

patterns. The neoprene rubber walls damp the waves that

would reflect and disturb the primary wave and interfer-

ence patterns. The tempered glass bottom ensures a uni-

form water depth for all ripple tank experiments. A smallhole in the glass bottom and a standard rubber stopper

make draining the tank easy. The tank legs are removable

and can be stored in the tank itself so multiple tanks can

be stacked on top of one another. Each tank is shipped in

protective reusable packing for easy storage.

WA-9773 Ripple Tank specifications:

width 47.5cm X 47.5cm (19 X 19)

height 45cm minimum (feet of tank legs are

adjustable)

viewing area 39.5cm X 39.5cm (16 X 16)

water capacity 1.2-2.0 liters (1.1-1.8 quarts) or 6-

8mm (.25-.32), 8-10mm (.32-

.40) deep for refraction experiments

Equipment

The WA-9773 Ripple Tank includes the following:

glass tank with rubber gasket

steel tank frame

tank legs (4) with adjustable feet

triangular refractor

convex refractor

concave refractor

curved reflector

mini straight reflector

short straight reflector

long straight reflector (2)

rubber stopper

clear plastic cm/inch rule

1995 PASCO scientific

This instruction sheet written/edited by:

Mary Ellen Niedzielski

tank with rubber wallsand glass bottom


4/40

2

Ripple Tank 012-05837A

Assembly

To assemble the tank, screw a leg into the bottom of each

of the four corners of the tank frame. Place the glass plate

into the top of the tank frame so the rubber sides form a

basin for the water. If the glass plate does not touch the

tank frame at all four corners, use the leveling feet to re-shape the frame to fit the glass plate. Insert the rubber

stopper into the drain hole in the glass plate and push

down on it to make sure the water will not leak out. See

Figure 1.

When filling the tank with water, the water level must be

above the step on the rubber boundary so reflections will

be minimized. Most experiments require from 1.2 liters to

2.0 liters of water. The tank can be leveled by checking

the depth of the water in three of the four corners.

Cleanup and Storage

To empty the tank, place a container under the drain hole

and remove the rubber stopper. When the water stops

flowing out of the hole, raise the corner of the tank oppo-

site the hole so the rest of the water will drain out. Use a

towel to dry the glass tank. Replace the rubber stopper for

storage. Store the glass tank in its custom shipping box.

ripple tank leg (4)

steel tank

frame

Figure 1: Ripple Tank Assembly

Limited Warranty

PASCO scientific warrants this product to be free from

defects in materials and workmanship for a period of oneyear 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. 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 ship-ment will not be covered by the warranty.) Shipping costs

for returning the equipment, after repair, will be paid by

PASCO scientific.

Equipment Return

Should this product have to be returned to PASCO scien-

tific, for whatever reason, notify PASCO scientific by let-

ter or phone BEFORE returning the product. Upon notifi-

cation, the return authorization and shipping instructions

will be promptly issued.

NOTE:

NO EQUIPMENT WILL BE ACCEPTED FOR

RETURN WITHOUT AN AUTHORIZATION.

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 fol-

lowing rules:

The carton must be strong enough for the item

shipped.

Make certain there is at least two inches of packing

material between any point on the apparatus and the

inside walls of the carton.

Make certain that the packing material cannot shift in

the box, or become compressed, thus letting the instru-

ment come in contact with the edge of the box.

glass tank withrubber gasket

rubberstopper

leveling foot


5/40

Instruction Manual andExperiment Guide forthe PASCO scientific

Model WA-9775

012-05846A

11/95

1995 PASCO scientific $10.00

BASIC RIPPLETANK SYSTEM


6/40


7/40

i

012-05846A Basic Ripple Tank System

Table of Contents

Section PageCopyright, Warranty, and Equipment Return ................................................... ii-iii

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

Equipment ........................................................................................................ 2

Assembly

Assembly of the Tank ................................................................................. 4

Clean-up and Storage .................................................................................. 4

Mounting the Light Source .......................................................................... 5

Mounting the Ripple Generator ................................................................... 5

Generator Attachments ........................................................................... 6

Height Adjustment ................................................................................. 6

Frequency Adjustment ........................................................................... 6

Amplitude Adjustment ........................................................................... 7

Phase Difference .................................................................................... 7

Experiments

Exp 1 Reflection ......................................................................................... 9

Exp 2 Refraction ........................................................................................ 13

Exp 3 Diffraction ....................................................................................... 17

Exp 4 Interference ...................................................................................... 21

Exp 5 Image Formed by a Plane Mirror ...................................................... 25

Exp 6 Dependence of Wave Speed on Water Depth ................................... 27

Technical Support ...................................................................................... Back Page


8/40

ii

Basic Ripple Tank System 012-05846A

Copyright, Warranty and Equipment Return

Copyright Notice

The PASCO scientific 012-05846A Basic Ripple Tank

System manual is copyrighted and all rights reserved.

However, permission is granted to non-profit educational

institutions for reproduction of any part of the (manual

title) 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

workmanship. 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 equip-

ment after repair will be paid by PASCO scientific.

Credits

Author: Jon HanksEditor:

PleaseFeel free to duplicate this manual

subject to the copyright restrictions below.

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.

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:

The packing carton must be strong enough for the

item shipped.

Make certain there are at least two inches of

packing material between any point on the

apparatus and the inside walls of the carton.

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: (916) 786-3800

FAX: (916) 786-3292

email: [email protected]

web: www.pasco.com

NOTE: NO EQUIPMENT WILL BE

ACCEPTED FOR RETURN WITHOUT AN

AUTHORIZATION FROM PASCO.


9/40

1


Introduction

The WA-9775 Basic Ripple Tank System consists of

three components which enables the user to perform ex-

periments and to demonstrate basic wave and optics

theory. Each component is described below.

The WA-9773 Ripple Tank is the core of the Basic

Ripple Tank System and allows the user to create wave

patterns. The neoprene rubber walls damp the waves that

would reflect and disturb the primary wave and interfer-

ence patterns. The tempered glass bottom ensures a uni-

form water depth for all ripple tank experiments. A small

hole in the glass bottom and a standard rubber stopper

make draining the tank easy. The tank legs are removable

and can be stored in the tank itself so multiple tanks can

be stacked on top of one another. Each tank is shipped inprotective reusable packing for easy storage.

WA-9773 Ripple Tank specifications:

width: 47.5cm X 47.5cm (19 X 19)

height: 45cm minimum (feet of tank legs are

adjustable)

viewing area: 39.5cm X 39.5cm (16 X 16)

water capacity: 1.2-2.0 liters (1.1-1.8 quarts) or 6-

8mm (.25-.32), 8-10mm (.32-

.40) deep for refraction experimentsThe WA-9776 50W Halogen Point Light Source provides

a bright, nearly perfect point source for sharp wave pat-

tern projection. The point source is created by placing the

halogen light so the filament sits perpendicular to the

tank. The filaments position means the tip of the fila-

ment, rather than the length, faces the surface of the wa-

ter. The light source includes a built-in rod clamp.

WA-9776 50W Point Light Source specifications:

bulb type: 50W, 12 volt, type T-4 halogen

power requirements: 100-240 VAC

The WA-9777 Basic Ripple Generator can produce true

sinusoidal motion when the universal dippers (rubber

actuators) are used. Plane wave and multiple point wave

sources can also be produced with the included plane

wave actuator bar. A DC motor driving a pair of cams

provide the wave motion, with a phase adjustment of 0-

360, on two separate points. The WA-9777 uses a

phase lock knob to prevent the phase from changing un-

expectedly while in use. The three adjustment screws ac-

curately position the plane wave actuator bar or one or

two rubber actuators on the surface of the water. The

mount is mechanically isolated from the ripple tank

which ensures sharp wave patterns. The mechanical

ripple generator includes a built-in rod clamp.

NOTE:Loosen the phase lock knob to adjust the

phase and tighten to lock the phase in. Tighten just

enough to prevent the phase from changing due to

the vibration of the ripple arms. Over tightening

may cause a decrease in frequency.

WA-9777 Basic Ripple Generator specifications:

frequency: 2-20Hz

amplitude: 0.5-2mm (.02-.08) peak-

to-peak

dipper diameters: 0.6 (.25), 2.0 (.79), and

3.2 cm (1.25) diameters

plane wave attachment: 30cm (12) long

power supply: 9 VDC adapter (included)


10/40

2


Equipment

rubberstopper

tank legs (4)

tank frame

mini straightreflector

short straightreflector

long straightreflector (2)

convex refractor

clear plasticrule

concave refractor

triangularrefractor

curvedreflector

WA-9773 Ripple Tank Equipment

tank with rubber wallsand glass bottom

The WA-9773 Ripple Tank includes the following:

glass tank with rubber gasket steel tank frame

tank legs (4) with adjustable feet


convex refractor

concave refractor

curved reflector mini straight reflector



rubber stopper

clear plastic cm/inch rule

WA-9776 50W Halogen Point Light

Source Equipment

WA-97

76

50WHAL

OGEN

POINT

LIGHT

SOURCE

light sourceassembly with rod

clamp

The WA-9776 50W Halogen Point Light Source

includes the following:

light source assembly with rod clamp


11/40

3


FREQUENCY

AMPLITUDEADJUST

A

MIN

MAX

7

6

5

4

3

2

1

G

BC

D

E

F

HI

J

PHASE360

270

180

900

WA-9777 Ripple Generator Equipment

plane wave actuatorbar assembly

small rubberactuators (3)

actuatorforearms (2)

mechanical ripplegenerator assembly

large rubberactuators (3)

FREQUENCYAMPLITUDE ADJUST

A

MINMAX

7 6 5 4 3 2 1

G

B C

D

E

F

HI

J

PHASE

360

270

18090

0

CAUTION!

LOOSEN

PHASE

LOCK

KNOB

ON

OPPOSITE

SIDE

BEFORE

ADJUSTING

PHASE

9 VDC500mAAMPLITUDE ADJUST

MAXMIN

1 2 3 4 5 6 7

WA-9777 BASICRIPPLE GENERATOR

GND

+9VDC3.5mmLOOSEN TO

ADJUST

TIGHTEN TO

LOCK

PHASE LOCK KNOB

power input jack

rod clamp

amplitude adjustment(1mm - 4mm peak-to-peak)

ripple arm

frequency adjust

(0-20 Hz)

phase adjust

tiltsgenerator

raises andlowers ripple

arms

three pronged clip formounting actuatorforearms

Mechanical Ripple Generator Assembly Control and Details

phase lock

The WA-9777 Basic Ripple Generator includes the

following:

mechanical ripple generator assembly with rod

clamp

small rubber actuators (3)

large rubber actuators (3)

plane wave actuator bar with screws (8) for creating

multiple point sources

forearms (2) for attaching plane wave actuator or

rubber actuators to the mechanical ripple generator

assembly

9VDC power adapter


12/40

4


Assembly

steel tank frame

ripple tank leg (4)

Figure 1: Ripple Tank Assembly

rubber stopperglass tank withrubber gasket

leveling foot

When filling the tank with water, the water level must be

above the step on the rubber boundary so reflections will

be minimized. Most experiments require from 1.2 liters to

2.0 liters of water. The tank can be leveled by checkingthe depth of the water in three of the four corners.

Cleanup and Storage

To empty the water from the tank, place a container under

the drain hole and pull the plug. When the water stops

flowing out of the hole, raise the corner of the tank oppo-

site the hole so the rest of the water will drain out. Use a

towel to dry the glass tank. Replace the plug for storage.

Store the glass tank in its custom shipping box.

WA-9773 Ripple Tank

Assembly of the Tank

To assemble the tank, screw a leg into the bottom of eachof the four corners of the tank frame. Place the glass plate

into the top of the tank frame so the rubber sides form the

basin for the water. If the glass plate does not touch the

tank frame at all four corners, use the leveling feet on the

legs of the tank to reshape the frame to fit the glass plate.

Insert the rubber stopper into the drain hole in the glass

plate and push down on it to make sure the water will not

leak out. See Figure 1.


13/40

5


WA-97

76

50WHA

LOGEN

POINT

LIGHT

SOURCE

Figure 2: WA-9776 50W Point Light

Source Assembly

ME-8735 large rodstand

(not included)

ME-873890cm rod

(not included)

SE-9444 rightangle rod clamp(not included)

light sourceassembly with

rod clamp

ME-8736 45cm rod(not included)

FREQUENCY

AMPLITUDEADJUST

A

MIN

MAX

7

6

5

4

3

2

1

G

BC

D

E

F

HI

J

PHASE360

270

180

900

Figure 3: WA-9777 Ripple Generator

ME-8735 large rodstand

(not included)

mechanical ripplegenerator assembly

with rod clamp

ME-873890cm rod

(not included)

WA-9776 50W Halogen Point Light Source

Mounting the Light Source

All experiments require a point light source such as the

PASCO Halogen Light Source (WA-9776).

A PASCO ME-8735 Large Rod Stand and either theME-8738 (90cm) or ME-8741 (120cm) support rod are

needed to mount the light source. See Figure 2. Mount the

light source above the ripple generator on the same rod

stand. It is preferable to have the light source at least 50

cm above the tank. At this distance, the halogen filament

more closely approximates a point light source and the

waves cast well-defined shadows onto the paper on the

table beneath the ripple tank. See Figure 2.

WA-9777 Ripple Generator

Mounting the Ripple Generator

Mount the ripple generator below the light source on the

same lab stand. See Figure 3. The use of two support rods

mounted side-by-side in the large base with a cross-sup-

port will provide the ripple generator a particularly sturdy

support. Mount the ripple generator on the support rod

using the generators rod clamp. To prevent any unwanted

vibrations, the ripple generator should be positioned just

above the edge of the tank so it does not make contact

with the tank. The ripple generator is powered by a 9-Volt

adapter which plugs into the side of the generator.

NOTE:When the PASCO ME-8735 Large RodStand is used setting up the WA-9775 Basic Ripple

Tank System, the complete system can be setup us-

ing a single rod stand. For best results, setup the

equipment as shown in Figure 6.


14/40

6


Generator Attachments

Attachments of various sizes and shapes are sup-

plied with the ripple generator to create different

types of waves. The system includes a plane-wave

attachment and two different sizes of point source

attachments: large and small rubber actuators. Theplane wave actuator is a bar that can be attached to

the ripple generator by inserting the actuator fore-

arms from the ripple arms of the ripple generator

assembly into the holes in the plane wave actuator

bar. Note the orientation of the bar with respect to

the tank. See Figure 4.

The ripple generator arms are the two molded plastic

arms that protrude out of the front of the ripple gen-

erator. Each ripple generator arm has a bent wire

(actuator forearm) that must be inserted into the

three pronged clip at the tip of each ripple arm. SeeFigure 4. The actuator forearms can be used to adjust the

height of the actuator by sliding the forearm up or down

in the ripple generator arm. The plane wave actuator bar

also has screws which act as multiple point sources when the

plane wave actuator bar is inverted on the actuator arms.

The point sources (small and large rubber actuators) are

rubber disks that slide onto the actuator forearms on the

ripple generator. A total of four different sizes of point

sources can be achieved using the two rubber actuators

supplied. The four sizes include the large rubber actuator,

the small rubber actuator used with its larger side down,

the small rubber actuator used with its smaller down, and

the actuator forearm used without any attachment. In gen-

eral, the greater the frequency of the ripple generator, the

smaller the point source attachment should be to produce

the best looking circular waves. Please see the Equip-

ment section illustrations.

Height Adjustment

The ripple generator may be tilted left-to-right or front-to-

back using the three thumb nuts on the top of the ripple

generator. With these thumb nuts, fine adjustments in the

depth of the actuators can be made without moving the

whole ripple generator on its rod stand or moving the

bent-wire actuators. Screwing the front thumb nut down

will raise the actuator out of the water. Screwing one of

the back thumb nuts down will lower the actuator on the

side opposite to the thumb nut that is used.

Frequency Adjustment

The frequency of the ripple generator can be adjusted

from 0 Hz to 20 Hz. The frequency knob is marked with

the letters A (0 Hz) through J (20 Hz) in approximately

even intervals so the user may repeat experiments by

*Diagram from Water Waves in a Ripple Tank by Goro

Kuwabara, Toshihiro Hasegawa, and Kimitoshi Kono, Ameri-

can Journal of Physics, Vol. 54, No. 11, November 1986, page

1003.


A

MINMAX

7 6 5 4 3 2 1

G

B C

D

E

F

HIJ

PHASE360

270

18090

0

water

WA-9773Ripple Tank

mechanicalripple generator

assemblyheight adjustment

thumbnuts

ripple arm

actuator

forearm

plane waveactuator bar

Figure 4: Ripple Generator with Plane Wave Attachment

knowing to what letter the frequency was set. In general it

is necessary to use frequencies less than 5 Hz for refrac-

tion experiments because the speed of the waves for dif-

ferent depths is the same for frequencies above about 10

Hz. See Figure 5.

Amplitude Adjustment

The amplitude of each actuator arm can be adjusted by

loosening the thumb nut on the amplitude adjust and slid-

ing the indicator to the desired position and tightening the

thumb nut at this position. The amplitude can be varied

from about 1 mm to 4 mm peak-to-peak. This is indicated

on a scale of 1 (minimum) to 7 (maximum) on the label.

Frequency (Hz)1

Velocity(cm/sec)

2 5 1010

20

30

50

70

20 30

Figure 5: Dispersion Relation of Waves as aFunction of Depth*

2cm

1cm

0.5cm

0.2cm

h = 4cm


15/40

7



A

MINMAX

7 6 5 4 3 2 1

G

B C

D

E

F

HIJ

PHASE360

270

18090

0

Figure 6: Mounting the Complete WA-9775 Basic Ripple Tank System using one ME-8735 Large Rod Stand

50cm

WA-9777 BasicRipple Generator

ME-8735 LargeRod Stand

SE-9444 rightangle rod clamp(2, not included)

ME-8741 120cm rod(2, not included)

ME-8736 45cm rod(not included)

WA-9773 RippleTank

WA-9776 50W Halogen

Point Light Source

The numerical reference allows the user to set the same

amplitude on each side by setting each indicator to the

same number.

Phase Difference

The phase difference between the two actuators can be ad-

justed from zero to 360 degrees using the phase knob nearthe frequency knob on the side of the ripple generator.


16/40

8


Notes:


17/40

9


Experiment 1: Reflection

EQUIPMENT REQUIRED

Ripple Tank (WA-9773) straight barrier (triangular refractor)

curved barrier (concave refractor)

clear metric rule

50W Halogen Point Light Source (WA-9776)

Ripple Generator (WA-9777)

plane wave actuator bar

protractor

drawing compass

paper (40 cm x 40 cm)

rod stand (90 to 120 cm long)

PurposeTo study the reflection of a plane wave from different shaped barriers.

Theory

When a ray reflects off a surface, the angle of incidence

is the angle between the incoming (incident) ray and the

normal. The angle of reflection is the angle between the

outgoing (reflected) ray and the normal. The normal is a

line that is perpendicular to the surface. See Figure 1.1.

Wave fronts are perpendicular to the rays.

Setup

Type of Actuator: Plane Wave Actuator Bar

Water Depth: 5mm

Actuator Depth: touching water surface

Frequency: 5-10Hz

Amplitude: maximum

Fill the tank with water to a depth of about 5 mm so the water is just above the step in the rubber

gasket. The depth of the water must be less than the thickness of the plastic barrier.

Level the tank.

Put the plane wave actuator bar on the ripple generator. Adjust the height of the ends of the bar

so the bar is level with the surface of the water. Then lower the whole ripple generator until the

bottom of the bar is submerged about half way down.

Loosen the phase lock knob, set the phase setting to zero, retighten the phase lock knob.

Set the amplitude to the maximum setting.

Set the frequency to setting C.

Plug in the ripple generator and the light source.

Figure 1.1: Definition of Angles

wav

efront

incidentrayrefle

cted

ray

normal

ri


18/40

10


Part I: Reflection Using a Straight Barrier

Figure 1.2: Position of Straight Barrier

mechanical ripplegenerator


straight barrier(triangular reflector)

ripple tank

Procedure

Place the straight barrier in the water at an angle to the incoming plane waves. See Figure 1.2.

On the paper below the tank, place the metric rule parallel to the plane waves that are incoming to

the barrier. Make a line to show the incoming wave front.

Align the rule with the reflected wave and make a line to show the reflected wave.

Trace the position of the straight barrier.

Turn off the light source and ripple generator.

Draw a line that is perpendicular to the incoming wave front. Extend it to the straight barrier. This

represents the incoming ray so draw an arrow on it pointing toward the barrier.

Draw a line from the point where the incoming ray strikes the barrier so it crosses the reflected

wave front at a right angle. This represents the reflected ray so draw an arrow on it pointing away

from the barrier.

Draw the normal (perpendicular) line at the point of reflection on the barrier.


19/40

11


Measure the angle of incidence, i, and the

angle of reflection, r. What is the relationship

between these angles? Record the results in

Table 1.1.

Repeat this procedure with the barrier at a different angle.

Part II: Reflection Using a Curved Barrier

Angle of Incidence

Angle of Reflection

Trial #1 Trial #2

Table 1.1 Reflection Results

Procedure

Replace the straight barrier with the circular barrier and position as shown in Figure 1.3.

Trace the position of the circular barrier on the paper.

Mark the position on the paper where the reflected waves converge.

Turn off the ripple generator.

Use the tip of your finger to produce a circular pulse at the marked position where the waves

converged.

What is the shape of the pulse after it is reflected off the barrier?

mechanical ripple

generator plane waveactuator bar

ripple tank

Figure 1.3 Position of Circular Barrier

circular barrier(concave refractor)


20/40

12


To locate the center of the circle, use the drawing compass to trace the circular shape of the bar-

rier. Mark the center of the circle and measure the radius.

How is the radius of the circle related the distance between the circular barrier and the point

where the reflected waves converged?


21/40

13


Experiment 2: Refraction

EQUIPMENT REQUIRED

Ripple Tank (WA-9773) triangular refractor

concave refractor

convex refractor

clear metric rule




9 identical coins (to adjust the height of the triangular refractor)



PurposeThe purpose is to show how waves bend as they pass from one medium to another.

Theory

As a wave passes from one medium to another, it changes speed. If it slows down, the wave will

bend toward the normal as shown in Figure 2.1. This bending is called refraction.

Figure 2.1: A Wave Slowing Down

medium #2

medium #1

interface between twomediums

Setup


Water Depth: 10mm

Actuator Depth: deep as possible

Frequency: setting A or B (2-5Hz)Amplitude: maximum

Fill the tank with water to a depth of about 10 mm.

Level the tank.



bottom of the bar is submerged as far down as possible, leaving room for the bar to oscillate. If


22/40

14


the bar hits the bottom of the tank when it oscillates, raise it until it just barely clears the bottom

of the tank while oscillating.



Set the frequency to setting A or B.


Part I: Refraction Using a Straight Refractor




ripple tank

Figure 2.2: Position of Triangular RefractorProcedure

Place the triangular refractor in the water at an angle to the incoming plane waves. See Figure 2.2.

To simulate two different mediums, the depth of the water must change. Raise the triangular

refractor by placing an equal number of coins under each corner of the triangle. Adjust the height

in this manner so the depth of the water on top of the triangle is only 2 to 3 mm.

On the paper below the tank, place the metric rule parallel to the plane waves that are incoming to

the refractor. Make a line to show the incoming wave front.

Align the rule with the refracted wave over the triangle and make a line to show the refractedwave.

Trace the position of the edge of the triangular refractor that the wave hits.

Turn off the light source and ripple generator.

Draw a line that is perpendicular to the incoming wave front. Extend it to the edge of the triangu-

lar refractor. This represents the incoming ray so draw an arrow on it pointing toward the triangle.


23/40

15


Draw a line frm the point where the incoming ray strikes the triangle so it crosses teh reefracted

wave front at a right angle. This represents the refracted ray so draw an arrow on it showing

which way the wave is traveling.

Draw the normal (perpendicular) line at teh point of refraction on the triangle.

When the wave goes from the deep water to the shallow water in the triangle area, does the wave

bend toward or away from the normal?

When the wave goes from the deep water to the shallow water in teh triangle area, does teh wave

speed up or slow down?

Part II: Refraction Using Curved Refractors

Procedure

Replace the triangular refractor with the convex refractor, placing it a few centimeters from the

plane wave generator.

Turn on the ripple generator and trace the pattern seen.

Measure the focal length of the lens. This is the distance from the center of the lens to the place

where the plane waves are focused.

Replace the convex refractor with the concave refractor and trace the pattern seen.


24/40

16


Notes:


25/40

17


Experiment 3: Diffraction

EQUIPMENT REQUIRED

Ripple Tank (WA-9773) triangular refractor



clear metric rule






Purpose

The purpose of this experiment is to determine how the diffraction pattern changes as the slit

width and the wavelength are varied.

Setup


Water Depth: 7mm


Frequency: 10Hz (setting E)

Amplitude: setting 4


gasket. Level the tank.



bottom of the bar just touches the surface of the water.


Set the amplitude to setting #4.

Set the frequency to setting E.


Procedure

Place the two long straight reflector about 3 cm apart in the water as shown in Figure 3.1.


26/40

18


On the paper below the tank, trace the reflectors and roughly trace the angle that the waves spread

out when they pass through the slit. Make a sketch of the wave pattern here.

Change the slit width to about 1.5 cm by sliding the two reflectors closer together.

On the paper trace the new angle that the waves spread through. Is this angle more or less than the

angle for the wider slit?

Figure 3.1 Position of Straight Barriers

3cm

straight barriers(long straight reflectors)

ripple tank

mechanical ripplegenerator plane wave

actuator bar


27/40

19


Keeping the same slit width of about 1.5 cm, increase the frequency of ripple generator to setting

J.

How does increasing the frequency affect the wavelength?

How does increasing the frequency change the spread angle?

Replace the slit with the mini straight reflector. Remove the two long straight reflectors. See

Figure 3.2.

ripple tank


actuator bar

straight barrier(mini straight reflector)

Figure 3.2: Diffraction for a Solid Object

Sketch the resulting wave pattern here.

How does this pattern compare to the same-size slit pattern?


28/40

20


Notes:


29/40

21


Experiment 4: Interference

EQUIPMENT REQUIRED

Ripple Tank (WA-9773) long straight reflector (2)


clear metric rule






Purpose

The purpose of this experiment is to determine how the interference pattern changes as the slit

separation and the wavelength are varied.

Theory

When a wave passes through two slits, the positions of maximum intensities are given by

dsin=m(where m= 0, 1, 2,)

where d is the slit separation,is the angle between maxima, is the wavelength, and m is

the order. See Figure 4.1.

screenslits

a

d

maximum

maximum

Figure 4.1: Double-slit

SetupType of Actuator: Plane Wave Actuator Bar

Water Depth: 7mm


Frequency: 10Hz (setting E)



gasket.


30/40

22


Level the tank.

Put the plane wave actuator bar on the ripple generator. Adjust the height of the ends of the bar so

the bar is level with the surface of the water. Then lower the whole ripple generator until the




Set the frequency to setting E.


Procedure

Place the short straight reflector between the two longest reflectors to form two openings about 2

cm long as shown in Figure 4.2.

ripple tank


actuator bar

2cm

2cm

straight barriers

(long straight reflectors)

straight barrier(short straight reflector)

Figure 4.2: Position of Straight Barriers

On the paper below the tank, trace the reflectors and roughly trace the angles that the waves

spread out when they pass through the slit. Find the regions where the waves from the two slits

tend to cancel each other and find the regions where the waves add together to make waves with

higher peaks. Make a sketch of the wave pattern here.


31/40

23


Figure 4.3: Interference Using Two Point Sources

ripple tank

mechanical ripplegenerator point sources

(small rubberactuators, 2)

Decrease the slit separation by the replacing the center reflector with the mini straight reflector

but keep the slit width at 2 cm.

Does the spread angle of the wave increase or decrease?

Keeping the same slit width of about 2 cm and the same slit separation, increase the frequency

of ripple generator to setting J. This decreases the wavelength. How does decreasing the wave-

length change the spread angle?

Now remove the straight barriers from the tank and replace the plane wave actuator bar with two

point sources (large end of the small rubber actuators) as shown in Figure 4.3. Using the same

settings, compare the point source wave pattern with the two-slit pattern.


32/40

24


Notes:


33/40

25


Experiment 5: Image Formed by a Plane Mirror

EQUIPMENT REQUIRED

Ripple Tank (WA-9773) straight barrier (triangular refractor)

clear metric rule



point source (small rubber actuator)



Purpose

The purpose is to show the position of the image formed by a plane mirror.

Setup

Type of Actuator: one medium point source (large side of small rubber actuator)

Water Depth: 7mm


Frequency: setting A (2-3Hz)



gasket.

Level the tank.

Put the point source (small rubber actuator) on the ripple generator. Adjust the height of thepoint source until it just touches the surface of the water.



Set the frequency to setting A.



34/40

26


Figure 5.1: Straight Barrier

ripple tank

mechanical ripplegenerator point source

(small rubber actuator)

Procedure

Place the straight barrier in the tank as shown in Figure 5.1.

On the paper below the tank, mark the position of the point source and the position of the straight

barrier. Measure the perpendicular distance from the barrier to the point source.

Record this distance here:___________________

Lay a ruler on the paper with one end of the ruler on any point on the line that indicates the bar-

rier. Orient the ruler so it crosses the reflected wave fronts at a right angle. Draw a line along the

ruler in this position.

Move the end of the ruler to a new point on the barrier line and orient it so it again crosses the

reflected wave fronts at a right angle. Draw a line along the ruler in this new position.

Extend the two ruler lines until they cross. The point where they cross is the center of the re-

flected circles. This center represents the position of the image.

Is the image located on the same side of the barrier as the point object?___________

Measure the perpendicular distance from the barrier to the image of the point source. Record this

distance here:___________________

How is this distance related to the distance between the point source and the barrier?


35/40

27


Experiment 6: Dependence of WaveSpeed on Water Depth

EQUIPMENT REQUIRED

Ripple Tank (WA-9773)

straight barrier (triangular refractor)

clear metric rule




protractor

6 identical coins (to adjust the height of the triangular refractor)



stopwatch

Purpose

The purpose is to determine the dependence of wave speed on water depth and to show how

waves break on a shore.

Setup


Water Depth: 10mm


Frequency: setting B (4Hz)

Amplitude: maximum

Fill the tank with water to a depth of 10 mm.

Level the tank.






Set the frequency to setting B.



36/40

28


Figure 6.1: Experiment Setup



triangular reflector

ripple tank

water

Part I: Breaking Waves On Shore

Procedure

Place the triangular refractor in the tank as shown in Figure 6.1. Place several coins under one

corner of the triangle so it slants up out of the water. This causes the water depth to change and

forms the beach.

Observe the plane waves as they approach the beach.

At what angle do the wave fronts meet the beach?

Sketch the path of the wave fronts as they travel from the ripple generator to the shore.

glass

coins

coins


37/40

29


Part II: Wave Speed

Procedure

Lay the clear plastic metric rule in the water so it is perpendicular to the wave fronts. Follow the

movement of a wave front by running your finger along the projected image of the ruler on thepaper below the tank, keeping your finger pointed at a particular wave front. Use the stopwatch

to time how long it takes your finger to run the length of the ruler.

Table 6.1: Wave Speed Versus Frequency

TimeFrequency Setting Wave Speed

Use

v = d/tto calculate the wave speed. Record in Table 6.1.

Change the frequency to setting D and find the speed of the wave again. Record in Table 6.1.

In order to produce a good wave, it may be necessary to decrease the amplitude as the frequency

is increased.

Change the frequency to setting G and find the speed of the wave again. Record in Table 6.1.

How does speed of the wave depend on frequency?

Return the frequency to setting B and set the amplitude for maximum. Record the wave speedpreviously found for the 10 mm deep water in Table 6.2.

Drain some of the water so the depth is 7 mm. Find the wave speed for this new depth. Record

in Table 6.2.

Repeat the last step for depths of 5 mm and 2 mm.

Table 6.2: Wave Speed Versus Water Depth

TimeDepth of Water (mm) Wave Speed

10

7

5

2

On a separate sheet of graph paper, plot wave speed as a function of the water depth.

How does speed of the wave depend on the depth of the water?


38/40

30


Notes:


39/40

31


Technical Support Feedback

Feedback

If you have any comments about the product or manual,please let us know. If you have any suggestions on

alternate experiments or find a problem in the manual,

please tell us. PASCO appreciates any customer feed-

back. Your input helps us evaluate and improve our

product.

To Reach PASCO

For technical support, call us at 1-800-772-8700 (toll-

free within the U.S.) or (916) 786-3800.

fax: (916) 786-3292

e-mail: [email protected]

web: www.pasco.com

Contacting Technical Support

Before you call the PASCO Technical Support staff, it

would be helpful to prepare the following information:

If your problem is with the PASCO apparatus, note:

Title and model number (usually listed on the

label);

Approximate age of apparatus;

A detailed description of the problem/sequence of

events (in case you cant call PASCO right away,

you wont lose valuable data);

If possible, have the apparatus within reach when

calling to facilitate description of individual parts.

If your problem relates to the instruction manual,

note:

Part number and revision (listed by month and

year on the front cover);Have the manual at

hand to discuss your questions.


40/40

Documents

Ondas Gerti a Naz