PASCO OS-8539 User Manual
®
Instruction Manual with
10
1
100
GAIN
LIGHT
SENSOR
C
I-
6
604A
POL
ARI
ZERMOUNT
Experiment Guide and
Teachers’ Notes
012-06575C
*012-06575*
Educational Spectrophotometer
Accessory Kit and System
OS-8537 and OS-8539
Educational Spectrophotometer Table of Contents
Quick Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Set Up
Mounting the Rotary Motion Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Mounting the Degree Plate and Light Sensor Arm. . . . . . . . . . . . . . . . . . . . . . . . . . . 6
More Information About the Degree Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Mounting the Aperture Bracket Light Sensor Mount and Light Sensor . . . . . . . . . . . 7
Mounting the Grating Mount. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Mounting the Spectrophotometer Base on the Optics Bench. . . . . . . . . . . . . . . . . . . 8
Rod Stand Mounting Clamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Mounting the Collimating Slits and Lens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Positioning the Collimating Slits and Lens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Mounting the Grating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Mounting and Positioning the Focusing Lens. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Procedures
Turning the Degree Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Masking the Light Source or the Spectrophotometer . . . . . . . . . . . . . . . . . . . . . . . . 11
Using the Data Acquisition Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
General Information About the Light Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
General Information About Slit Widths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Scanning a Spectrum. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Calibrating the Grating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Angular Resolution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Cuvettes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Other Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Activity 1: Emission Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Activity 2: Absorption (Dark Line) Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Teacher’s Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
i
Educational Spectrophotometer Table of Contents
ii
®
Model No. OS-8537 and OS-8539 Quick Start
1
0
1
1
0
0
G
A
IN
HIGH SENSITIVITY
LIGHT SENSOR
CI-6604
Quick Start
The following pages give an overview of the Spectrophotometer equipment setup.
Step One: Prepare the Rotary Motion Sensor by
removing the thumbscrew, three-step pulley, and
rod clamp.
thumbscrew
three-step pulley
Rotary Motion Sensor
rod clamp
Step Three: Attach the Rotary Motion Sensor to
the Base hinge with the two small thumbscrews and
attach the Pinion to the Rotary Motion Sensor shaft.
Spectrophotometer Base
Put the Pinion
on the shaft.
hinge
Use the thumbscrews to
attach the sensor.
Rotary Motion
Quick Start 3: Attach the Sensor and Pinion
Step Four: Put the Degree Plate/Light Sensor Arm
on the Base. Attach the Grating Mount, Light Sensor Mount, and Light Sensor. Position the Focusing
Lens.
Sensor
Quick Start 1: Prepare Rotary Motion Sensor
Step Two: Prepare the Spectrophotometer Base by
removing the two small thumbscrews and Pinion
and by rotating the hinge away from the Base.
Spectrophotometer Base
Remove the
Pinion
Quick Start 2: Prepare the Hinge
Rotate the
hinge.
Remove the
thumbscrews.
Light
Sensor
Light Sensor Mount with
Aperture Disk and Screen
Focusing
Lens
Grating
Mount
Degree
Plate
Light
threaded
Sensor
Arm
lock washer
wing nut
Quick Start 4: Degree Plate & Light Sensor Arm, Grating Mount,
Focusing Lens, Light Sensor Mount, and Light Sensor
post
1
Educational Spectrophotometer Accessory Kit and System Quick Start
®
GRATING MOUNT
FOR USE WITH
OS-8537
SPECTROPHOTOMETER
Optics Bench
T-slot
square nut
thumbscrew
hinge
Base
GAIN
10
100
1
Collimating
Lens
Collimating
Slits
Quick Start 6: Setup for Collimation
Degree
Plate
H
IG
L
IG
H
T
Grating
glass side faces light source
Quick Start 7: Attach the Grating
GAIN
10
100
1
Scan slowly and
continuously in
one direction.
central ray
(“zeroth order”)
first order spectral lines
first order spectral lines
Grating
Step Five: Put the Spectrophotometer Base onto
one end of the Optics Bench
.
Quick Start 5: Put Base onto Optics Bench
Step Six: Mount the Collimating Slits and Collimating Lens onto the Optics Bench. Set up a light
source. Adjust the Collimating Slits and Collimating Lens to collimate the light beam.
Step Eight: Set up the experiment in the data acquisition program.
1. Select the Light Sensor for Analog Channel A.
2. Select the Rotary Motion Sensor for Digital
Channels 1 and 2.
3. Set the Rotary Motion Sensor to high resolution (1440 Divisions/Rotation).
4. Create a calculation for “Actual Angular Position” based on the Angular Position data from
the Rotary Motion Sensor and the ratio of the
radius of the Degree Plate to the radius of the
small post on the Pinion (typically, a 60 to 1
ratio).
5. Select a Graph display. Set the vertical axis to
Light Intensity and the horizontal axis to your
calculation of “Actual Angular Position”.
6. Set the sampling rate to 20 Hz (20 measurements per second).
Step Nine: Scan the Spectrum
light
source
light ray
path
Step Seven: Attach the Grating to the mount so the
glass side of the Grating faces the light source.
CAUTION: Avoid touching the Grating surface.
1. Mask or hood the light source if necessary.
2. Move the Light Sensor Arm so the Light Sen-
sor is beyond the edge of the first order spectral
pattern.
3. Start recording data. Slowly and continuously
scan the spectrum. Scan the first order spectrum on one side of the central ray, through the
central ray, and through the first order spectrum on the other side.
2
Step Ten: Analyze Your Data
®
Model No. OS-8537 and OS-8539 Introduction
Grating Mount
Grating
Degree Plate
Light Sensor Arm
Spectrophotometer
Base
Collimating Slits
Collimating Lens
Pinion*
Cuvettes (2)
Focusing Lens
Rod Mounting
Clamps (2)
Figure 1a: Educational Spectrophometer Accessory Kit
Introduction
About This Manual
This manual describes the PASCO OS-8537 Educational Spectrophotometer Accessory Kit and the PASCO
OS-8539 Educational Spectrophotometer System. The OS-8537 Accessory Kit is designed to be mounted on the
Optics Bench of the OS-8515 Basic Optics System.
Components of the Kit
The OS-8537 Educational Spectrophotometer Accessory Kit (see Figure 1a) includes the following items:
Spectrophotometer Base Degree Plate with Light Sensor Arm
Grating Mount Grating (~600 lines per mm)
Focusing Lens Collimating Lens
Collimating Slits Cuvettes (2)
Rod Stand Mounting Brackets (2)
(*The pinion shown in Figure 1a can be mounted on a post on the Spectrophotometer Base when not in use.)
3
®
Educational Spectrophotometer Accessory Kit and System Description
Rotary Motion Sensor
Aperture Bracket
DIN-to-DIN cable High Sensitivity Light Sensor Optics Bench (60 cm) Aperture Bracket Holder
Figure 1b: Additional Components of the Spectrophotometer System
thumbscrew
post
Light Source
Collimating Slit
Collimating Lens Diffraction Grating
Focusing Lens
spectral line
Figure 2: Grating Spectrometer
Recommended Equipment for use with the Spectrophotometer Accessory Kit:
Basic Optics System (OS-8515) High Sensitivity Light Sensor (CI-6604)
Aperture Bracket (OS-8534) Rotary Motion Sensor (CI-6538)
Components of the System
The OS-8539 Educational Spectrophotometer System includes the items in the Spectrophotometer Accessory Kit
plus the following:
Optics Bench (60 cm) Rotary Motion Sensor (CI-6538)
High Sensitivity Light Sensor (CI-6604) Aperture Bracket (OS-8534)
GAIN
1
10
100
04A
CI-66
LIGHT
SOR
SEN
Recommended Equipment for use with both the Kit and the System:
Light Source (such as SE-9466 Mercury Spectral Tube) Rod, 45 cm (ME-8736) (2)
Spectral Tube Power Supply and Mount (SE-9460) Large Rod Stand (ME-8735) (2)
Description
The Spectrophotometer allows you to view and measure the spectral pattern (spectrum) produced by a
light source. The Collimating Slits and Collimating
Lens produce a narrow beam of parallel light rays.
The Grating disperses the beam of light into a spectrum with different colors at different angles but with
all of the light of a given color in a parallel beam. The
Focusing Lens focuses these parallel beams of color
into spectral lines (see Fig. 2). The narrow slit on the
Aperture Disk (part of the Aperture Bracket) allows
light of a single color to enter the High Sensitivity Light Sensor. The High Sensitivity Light Sensor (included
with the Spectrophotometer System) measures the intensity of the light while the Rotary Motion Sensor
(included with the Spectrophotometer System) measures the angle to which the light is diffracted by the Grating.
4
MOUNT
POLARIZER
®
Model No. OS-8537 and OS-8539 Set Up
G
A
IN
1
0
1
0
0
1
Figure 3: Spectrophotometer System (top view)
Collimating Slit
Collimating Lens
Diffraction Grating
Grating Mount
Light Sensor
Arm
Focusing
Lens
Aperture
Disk
High Sensitivity Light Sensor
Pinion
Rotary Motion Sensor
Degree Plate
Light
Source
Optics Bench
Figure 4: Spectrophotometer Base (top view)
Hinge
Large
Thrumb
screw
Small
Thrumb
screws
Magnetic Pad
Pinion
Index
Threaded Post
Figure 5: Prepare Rotary Motion Sensor
Thumbscrew
Three-step Pulley
Rotary Motion Sensor
Rod Clamp
You can find the wavelength of each color of light using the measured angle and the Grating spacing “d”.
m = d sin m = 0, 1, 2…
where d is the distance between the
rulings on the Grating, m is the order
of the particular principal maximum,
is the angle of the diffracted light,
and is the wavelength.
The Grating disperses the beam of
light into a first order spectrum and
higher order spectra. The higher
order spectra are broader and less
bright than the first order spectra, and
may overlap.
The Grating is blazed, so one side of
the spectrum is much brighter than
the other.
Set Up
This part of the manual describes how to set
up the Spectrophotometer System (see Fig. 3).
.
Mounting the Rotary Motion Sensor
This describes how to mount the Rotary
Motion Sensor to the hinge on the Spectrophotometer Base.
The top of the Spectrophotometer Base has a
short threaded post for centering the circular Degree Plate and for
holding the Grating Mount. It also has a magnetic pad for holding
the Degree Plate, and a triangular shaped index marker. One side
of the base has a post upon which the Pinion can be stored when it
is not in use. The other side has a spring-loaded hinge and two
small thumbscrews for mounting the Rotary Motion Sensor
(included in the Spectrophotometer System). On both sides of the
base are large thumbscrews and square nuts used for mounting
the Spectrophotometer Base on the Optics Bench (see Fig. 4)
The Rotary Motion Sensor has a three step pulley attached to its
shaft with a small thumbscrew. The sensor also has a rod clamp
attached at one end.
First, remove the small thumbscrew and three step pulley from
the Rotary Motion Sensor shaft. Then, remove the rod clamp
from the Rotary Motion Sensor (see Fig. 5).
Remove the two small thumbscrews from the threaded storage holes on the side of the Spectrophotometer Base
and set them aside for the moment. Remove the Pinion from the storage post on the opposite side of the Spectrophotometer Base and set the Pinion aside for a moment (see Fig. 6).
5
®
Educational Spectrophotometer Accessory Kit and System Set Up
Spectrophotometer Base
Remove
the pinion
Rotate
the hinge
Figure 6: Prepare the Hinge
Put the pinion
on the shaft
Use the thumb-
screws to attach
the sensor
Hinge
Figure 7: Attach the Sensor and Pinion
Figure 8: Degree Plate onto Base
Let the post on top of
the pinion rest
against the edge of
the Degree Plate.
Rotary Motion
Sensor
Light Sensor
Arm
Degree Plate
Rotate the hinge away from the side of the base until the hinge
is almost perpendicular to the base. Use the two small thumbscrews to fasten the Rotary Motion Sensor to the lower set of
holes on the inside of the hinge.
Place the Pinion all the way onto the Rotary Motion Sensor
shaft and tighten the Pinion on the shaft by turning the small
thumbscrew on the side of the Pinion (see Fig. 7).
Connect the Rotary Motion Sensor to the PASCO interface.
Mounting the Degree Plate and Light Sensor Arm
Remove the
thumbscrews
The Degree Plate and Light Sensor Arm are shipped as a unit.
The Light Sensor Arm is attached to the circular Degree Plate
with two small thumbscrews. The hole in the center of the
Degree Plate fits over the short threaded post on the top of the
Spectrophotometer Base.
Hold the Rotary Motion Sensor slightly away from the base so
the small diameter post on top of the Pinion is not in the way of
the edge of the Degree Plate. Position the hole in the plate over
the short threaded post on the top of the base. Place the Degree
Plate onto the Spectrophotometer Base. Let the small diameter
post on the top of the Pinion rest against the edge of the Degree
Plate (see Fig. 8).
Rotary Motion
Sensor
More Information About the Degree Plate
The ratio between the radius of the Degree Plate and the
radius of the small post on the top of the Pinion is
designed to be 60 to 1. In other words, the Pinion rotates
60 times for one rotation of the Degree Plate.
This assumed ratio of 60 to 1 is included in a calculation
for the actual angular displacement of the Degree Plate as
it turns during the measurement of a spectrum (see “Using
the data acquisition program” in the Procedure section).
Using the exact ratio of the Degree Plate to the small Pinion post can slightly improve the accuracy of measurement. To determine the exact ratio of the Degree Plate to
the small Pinion post, do the following to calibrate the
Degree Plate:
1. Remove the Light Sensor Arm from the Degree Plate by unscrewing the two small thumbscrews. (You can
store the thumbscrews in the empty threaded holes on the Light Sensor Arm.) Turn the Degree Plate so the
zero degree mark is exactly aligned with the index mark on the arm that extends from the Spectrophotometer
Base.
2. Start the data acquisition program. (See the software’s Help system or User’s Guide for more information.)
3. In the program, select “Rotary Motion Sensor” to be connected to the PASCO interface. If possible, set the
resolution of the Rotary Motion Sensor to 1440 Divisions/Rotation.
6
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