Purpose; the operation of PASCO Capstone
The purpose of this activity is to become familiar with the operation of PASCO Capstone.
Equipment
 1 Smart Pulley sensor (ME-9387)  2 Mass hangers
 1 1-m tall ringstand with flat base  1 Set of slotted masses
 1 Short aluminum bar  1 Meter stick
 1 Right-angle clamp  1 Roll of string
 1 Wireless force sensor (PS-3202)  1 0.5 kg hanging mass
 1 Hooked metal block
Introduction
You will use both automated (computerized) and manual (non-computerized) instruments to
perform each experiment in this course. You will use both computer sensors and manual
instruments to measure different properties of objects and substances. You will analyze your
measured data analytically and graphically (i.e., with equations and with graphs) and by
computer analysis routines.
Each computer sensor is a transducer of some type. It produces a voltage signal that is
proportional to the property being measured, and then feeds that signal into the Interface and
then into the computer. The PASCO Capstone program in the computer displays and records
the value of the measured property.
Sensors are available to measure many different basic properties and derived properties (such
as distance, time, speed, acceleration, rotary speed, force, pressure, brightness, frequency,
temperature, and loudness).
Our computerized lab system uses various electronic sensors, a PASCO 850 Universal
Interface unit, and the PASCO Capstone program running on the computer. This program
allows you to experimentally measure various basic properties, to calculate derived properties
that cannot be directly measured, to display, manipulate, and analyze the measured data to
obtain relationships between properties, and to obtain statistics on the precision of your
measurement data.
In this first experiment you will learn how to use the PASCO Capstone sensors and program
to collect and analyze data and how to report on the work you have done.
University Physics, Exp 2: Getting to Know PASCO Capstone Page 3
Theory
Setting up an Experiment
When you perform an automated experiment, you will measure the properties of interest with
electronic sensors. The sensors are connected to the PASCO 850 Universal Interface which is
connected to the computer. The Capstone computer program displays the collected data and
performs the desired analysis. However, it doesn’t write your lab report; you have to do that
yourself.
The PASCO 850 Interface is already connected to the computer. It is the silver, black, and
blue box under or beside the monitor.
Digital sensors plug into the digital channels on the upper left side of the Interface, and analog
sensors plug into the analog channels on the upper right side. The two types of sensor have
different connectors, so it is impossible to plug a sensor into the wrong type of channel.
PASPort sensors plug into the blue ports on the bottom. In some labs, we may add a
Bluetooth adapter to allow addition of wireless accessories to Capstone as well. These will be
in the computers before you attend lab. We will use one of these sensors today.
The Interface samples the output voltage signal from the sensor many times per second and
feeds the resulting digital values to the PASCO Capstone program in the computer. PASCO
Capstone then calculates the measurement values represented by the signal from the Interface
and displays them on the monitor.
PASCO Capstone can simultaneously accept samples from up to four digital sensors, up to
four analog sensors, and up to four PASPort sensors. It also allows you to enter data from the
keyboard to go with the data that is being collected by a sensor. For example, you might enter
the sensor’s position for PASCO Capstone to use in its analysis of the data from the sensor.
You can connect sensors to the interface at any time, but it is usually best to do so before
setting up the rest of your equipment.
First switch on the power to the computer and the Interface. When the computer completes its
start-up routine, it will display the Desktop on the monitor. Double-click on the PASCO
Capstone icon, and the PASCO Capstone window will appear with a QuickStart template
selection screen. Ignore this for now.
University Physics, Exp 2: Getting to Know PASCO Capstone Page 4
The menu bar in the PASCO Capstone window is similar to menu bars found in all Windows
programs. Below that, PASCO Capstone’s tool bar shows icons for managing files and
cutting or pasting items. Unlike previous versions of PASCO’s software, most of the tools for
managing sensors and data are hidden in the Tools Palette menus on the left side of the
screen.
To set up sensors, click the Hardware Setup icon in Tools Palette on the left side of the screen
within the PASCO Capstone window shown above. If your interface is on and functioning
properly, you should something like see the following appear. Even without the interface
present, Capstone may automatically search for wireless accessories. You will only detect
them if the Bluetooth adapter is plugged into the computer.
University Physics, Exp 2: Getting to Know PASCO Capstone Page 5
The Hardware Setup window shows the PASCO 850 Interface, the sensors that you can plug
into it, and the signal outputs available from it. To add a sensor (for example, the Motion
sensor), click on the yellow circle for the port you are using and then find the sensor in the list
that pops up. You can do this by scrolling through the list or typing in the sensor you are
using. The Motion sensor icon appears above digital channels 1 and 2 of the Interface. When
you are done adding sensors, click the Hardware Setup icon again to hide the window.
When adding a wireless accessory, take care to make sure you are selecting the one that
matches the serial number on the device. It will be a six digit number in the form XXX –
XXX. So a wireless device would appear as Smart Cart (Blue) 828 – 910 in the list of wireless
sensors.
After adding sensors, clicking the Data Summary icon will bring up the list of attached
sensors and the measurements they can take. In addition, the internal clock for the interface
and software is represented. For instance, below you can see the motion sensor, and the
Position, Velocity, and Acceleration data it can record as well as the internal clock. If you
have collected any data, you will see (editable) titles like “Run #1,” “Run #2,” etc. under each
of the measurements and an associated icon for that data set.
University Physics, Exp 2: Getting to Know PASCO Capstone Page 6
The other available tools, including the Timer Setup (not shown), Calibration, Calculator, and
Signal Generator tools will be addressed when needed.
Displaying the Data
To see the data collected by a sensor, or entered from the keyboard, or calculated by PASCO
Capstone, you must select a display. Each display appears in one of the journal pages shown
in the middle of the screen. If desired, you can add individual journal pages to separate data.
Within a journal page, you can drag or resize the display to suit your needs. You may use all
the displays simultaneously, or use more than one of each kind. The available displays are on
the right side of the screen in the Display Palette.
The Digits and Meter displays do not have a memory, i.e., they display only real-time data
unless statistics are selected – they do not save a measured value after its initial display. In
contrast, the Table and Graph displays not only show real-time values but continue to display
all values that have been collected.
During a typical data run, more samples are collected than can be displayed in the Table at
one time, but you can scroll down to see them all. You can rescale a Graph display so it will
show either all the collected data or an expanded view of only a selected portion of the data.
University Physics, Exp 2: Getting to Know PASCO Capstone Page 7
In addition to showing data samples that you have collected, the Table and Graph displays
can also provide a statistical analysis of the data. They can show the minimum, maximum,
mean, and number of samples in a data run and the standard deviation of those samples. The
Graph display can also determine a suitable equation (depending on the type of relationship)
to a selected portion of the plot. This is called curve fitting.
The Scope display provides a real-time graph of Data Signal vs. Time or some other variable;
and the FFT display shows Data Signal vs. Frequency. These generally will not be used until
PHYS 2426 if at all.
The Histogram display is not used in this course, but can be used to analyze data. The Text
Box, Image, and Video displays are all for completing reports completely within PASCO
Capstone, which we do not do at this time.
Selecting a Display
To view the data collected by any sensor in a particular display, double-click on that display
icon in the Display Palette or drag it into the journal page.
Digits Display
The Digits display (shown below) shows in a digital format values that the sensor is collecting
in real time. When you stop recording data, the last measured value remains on view.
You can control many features on the display. You can enlarge or shrink the display by using
the controls on the edge of the box. You can open more than one Digits display at once – each
displaying a different measurement.
The first three icons give you control of the number of decimal places displayed by the digits
display, but the default setting is usually optimal as it accounts for the sensor’s measurement
resolution. You may need to resize the window in order to see all the digits if you change the
number of digits displayed. While you are recording data, you can display a different
statistical value or the recorded values by selecting that feature on the Statistics menu. Only
one statistic can be displayed at a time.
University Physics, Exp 2: Getting to Know PASCO Capstone Page 8
Clicking the gear icon to at the right end of the toolbar opens the Display Properties window.
This gives you additional control of the appearance of your digits display, but should not be
necessary.
Graph Display
The Graph display plots values of any dependent variable on the ordinate (y) and values of
any independent variable on the abscissa (x). The Graph display can show relationships
between any two variables if they are present.
A single Graph display window can show multiple plots. For example, you can use the Graph
display window to show position versus time data, velocity versus time data, and/or
acceleration versus time data for a mass oscillating on a spring or for a freely falling object.
The origin of the graph will be the intersection of the minimum values on the two scales.
Clicking the Statistics button will show or hide selected statistics calculations. To open
the Statistics menu, click the down arrow button beside the Statistics button. On the resulting
Statistics menu, you can specify what will be shown on the Graph display. Choose the
statistics you want from the list. By default, the statistics being displayed apply to the entire
graph. To display statistics for a specific portion of the data, use the Highlighter tool and
resize the rectangle to select the portion you want to examine. You can highlight multiple
separate regions, if desired. The statistics will be superimposed on the selection.
University Physics, Exp 2: Getting to Know PASCO Capstone Page 9
Click the Fit button to see the list of analytical
relationships (mathematical formulas) for the plotted or selected
data, some of which are shown to the right. Each type of curve fit
corresponds to a particular form of equation between y and x.
PASCO Capstone calculates the values of the coefficients that
yield the best fit of the selected equation to the selected data
points.
When you select the Area tool, the program calculates and
displays the value of the area under (or above) the selected portion
of the plotted curve (the integral of the dependent variable).
When you select the Slope tool, the program calculates and
displays the value of the slope of the curve at the selected point
(the derivative of the dependent variable).
Clicking the Coordinate tool button lets you read the x and y coordinates of any data
point. The cursor becomes a large plus sign that extends vertically and horizontally to both
axes. The coordinates of the cursor appear in the label areas of each axis. You can add more
than one coordinate tool if desired. It also has the capability to display delta values if desired.
Click the Autoscale tool (on left) to zoom in on your highlighted portion of the
graph. Manual zooming can be accomplished with the mouse wheel while hovered over an
axis to adjust one axis or over the plot area to adjust both if desire.
Procedure
A. Smart Pulley Sensor
Plug the Smart Pulley sensor into Digital Input 1. This sensor consists of a low-friction
pulley with a built-in infrared beam passing through its spokes to a detector on the other side.
The sensor’s output signal drops from 1 volt to 0 volt whenever a spoke blocks the beam.
PASCO Capstone measures the brief time interval between spokes as the pulley rotates.
Knowing the number of spokes in the pulley, PASCO Capstone calculates the time interval
for one complete rotation of the pulley (its period T). The inverse of T is the pulley’s rotary
frequency in rotations/sec (f = 1/T). Knowing the pulley’s radius r, PASCO Capstone then
calculates the linear speed of the string passing over the pulley (v = 2πr/T).
1. Select Hardware Setup from the Tool Palette.
2. Click the circle on Digital Input 1. In the Sensors list, scroll down to Pulley with
Photogate and select it. In the Timer Setup tool, confirm that Linear Acceleration, Ch
1 (m/s2
) and Linear Speed, Ch 1 (m/s) are listed among the available measurements,
and click Data Summary again to hide it. If anything is missing, go to the Timer Setup
University Physics, Exp 2: Getting to Know PASCO Capstone Page 10
tool to enable the desired measurements. You can also do this to hide unwanted
measurements.
3. In the Display Palette, drag a Graph display to the journal page and resize it to your
liking. For the y-axis, click Select Measurement select Linear Speed. For the x-axis,
select Time. This is what we will call Graph 1. Then drag a second Graph display to
the journal page. For this one, select Linear Acceleration for the y-axis and select
Time again for the x-axis. This is Graph 2. Arrange Graph 2 and Graph 1 as you wish.
4. Using the right-angle clamp, attach the smart pulley to the top of the ring-stand. Be
careful not to unplug the smart pulley while doing this.
5. Cut a length of string about 1.5 meters long. Pass the string over the pulley and tie small
loops in both ends. Hang mass hangers from both loops. Adjust the pulley height so
that one hanger is a little bit below the pulley when the other hanger rests on the floor.
6. Stack 200 g of small-diameter slotted masses (not the larger-diameter ones) on the lower
hanger. This is mass m1. While holding your finger on the pulley to prevent it from
rotating, stack 210 g on the upper hanger. This is mass m2. Record the values of
masses m1 and m2 (be sure to include the mass of the mass hangers) in Table 1.
7. Click Record at the bottom of the screen and release the pulley. Observe the two graphs
while the pulley is moving. If any masses fall off of their hanger while moving (or if
the two mass hangers collide), stop the measurement, replace any masses that fall off
the hangers, and start over.
8. When the heavier mass hits the floor, click the stop button. Click the Autoscale tool on
both graphs, then drag a rectangle to select the linear portion of the plotted line in each
graph.
9. Click the down arrow to the right of the Fit button on the Velocity graph (Graph 1) and
select Linear Fit. PASCO Capstone writes a linear equation in its general form: y = mx
+ b and calculates the values of m and b for which the equation best fits the selected
portion of the Velocity graph. In the Velocity graph, the coefficient m (or slope) is the
acceleration of the masses. Record m from Graph 1 in Table 1. In the linear fit
window in Graph 1 PASCO Capstone reports an uncertainty associated with both b
and m. Since we do not know how PASCO Capstone arrives at those numbers, we will
not use them for our uncertainties in those measurements at this time.
10. Next, click the Statistics tool on the Acceleration graph (Graph 2) and record the Mean
value in Table 1.
11. Print the two graphs (Velocity and Acceleration) from PASCO Capstone (be sure
everyone in your group gets a copy).
12. Repeat steps 7-10 an additional nine times (for a total of 10 data runs). You only need to
print the two graphs once to include as an example in your lab report. Do not print the
graphs for all 10 data runs.
13. Calculate the mean and standard deviation for the 10 measured values of acceleration
for each graph, and record these values in Table 1.
14. Using the values of your measured acceleration, m1 and m2 and Newton’s second law,
calculate the value of the acceleration of gravity g for both graphs. Record this value
in Table 1.
15. Calculate the uncertainty in your calculated value of g for both graphs. Record this value
in Table 1
16. Calculate the percent error of your calculated value of g from your graphs. Record these
percent errors in Table 1.
17. Show all calculations, including calculations of uncertainty, on a separate calculations .18. Remove the pulley and replace it with the short bar. Discard the string and set the
pulley, mass hangers, and masses aside.
B. Force Sensor
Turn on your Wireless Force Sensor. This sensor has a small strain gauge that creates a
voltage that is proportional to the applied force (in addition to other things). Pulling on the
hook creates a voltage of one polarity; pushing on it creates a voltage of the opposite polarity.
1. Connect your Wireless Force Sensor to Capstone by selecting the one that matches the
serial number on your device from the Available Wireless Devices list below the
picture of the interface. It should be of the form Force Accel XXX – XXX. If you do not
see a list, click the Bluetooth symbol to make Capstone search for wireless devices if
you do not see “Searching for wireless devices…” If you are still having trouble, have
your instructor check to see the Bluetooth adapter at your station.
2. Clamp the force sensor to the short bar so that it hangs vertically, and hang the 0.5-kg
mass on its hook.
3. Click the Calibration tool in the Tools Palette and follow the on screen instructions as
below. The 0.5-kg mass has a weight of 4.90 N, so this two-point calibration lets
PASCO Capstone record the two voltages from the sensor that correspond to pulling
forces of 4.9 N and 0.0 N. It can then use this linear relationship between force and
voltage to calculate the force corresponding to any other voltage the sensor feeds to it.
1) Choose the type of measurement you would like to calibrate: Force
2) Choose the probes you would like to calibrate now: Force Measurements →
Wireless Force Sensor XXX – XXX: Force will automatically be selected.
3) Choose the type of calibration you would like to perform: Restore Factory
Calibration
4) Repeat Steps (1) and (2) to get back to the place where you can choose the
type of calibration. This time select: Two Standards (2 point). At this point,
make sure that the 0.5 kg hooked mass is hanging from your Wireless Force
Sensor.
5) Calibrate the first point: Standard Value = – 4.90 (The minus sign is very
important!). Click the Set Current Value to Standard Value button. Then
remove the mass to let the sensor hang with its hook empty.
6) Calibrate the second point: Standard Value = 0.00. Click the Set Current
Value to Standard Value button.
7) Review your calibration and accept. Check that the Live Value under the New
Calibration is near 0 N. Add the 0.5 kg mass back and make sure that the Live
Value increases to near -4.90 N. If it does, click Finish. Otherwise, try
stepping backwards fix any errors. If you still do not get a proper calibration,
ask your instructor for help.
4. Delete one or both of your Graph displays from Part A. In the Display Palette, drag a
Digits display to the journal page. If you deleted both Graph displays, also drag a
Graph display to the journal page. Arrange the Graph display and Digits display as
you wish on the screen. On the Graph display select Force for the y-axis and Time for
the x-axis. On the Digits display, select Force for the measurement.
5. You will now weigh an unknown mass (a metal block with a hook). To weigh your
unknown mass hang the mass on the sensor’s hook.
University Physics, Exp 2: Getting to Know PASCO Capstone Page 12
6. Click the Record button. After about 5 seconds, click the Stop button. Record the
reading, including units, from the Digits display in Table 2. Highlight the data in the
Graph display. Click the statistics button record the Mean value in Table 2. Print the
graph from PASCO Capstone (be sure everyone in your group gets a copy).
7. Repeat step 7 an additional nine times (for a total of 10 data runs). You only need to
print the graph once to include as an example in your lab report. Do not print the
graphs for all 10 data runs.
8. Calculate the mean and standard deviation for the 10 measured values of weight for both
the graph and digits display, and record these values in Table 2.
9. Weigh the unknown mass using a manually operated mass balance. Record the block’s
mass from this instrument, as well as the estimated uncertainty, in Table 2.
10. Calculate the weight of the unknown mass from the mass balance measurement, and
record it along with its uncertainty in Table 2.
11. Show all calculations, including calculations of uncertainty, on a separate calculations
page.
12. Calculate the percent difference between each value of weight measured using PASCO
Capstone (graph and digits) and the value of weight measured using the mass balance.
Record this percent difference in Table 2.
13. Return all equipment to the equipment cart as you found it, and be sure to turn off your
computer and PASCO interface and leave your lab table clean before exiting the lab.Student Name: REPORT
Section Number:

Instructions

1) Follow all of the lab activity steps given in the Lab Procedure.
2) Attach your completed data tables and graphs to this page.
3) TYPE YOUR ANSWERS IN THE PROVIDED SPACES below & in your data tables.
4) Attach additional sheets of paper that clearly (NEATLY) show all of your calculations performed
during this experiment.

Results

1) In Parts A and B, what sources of systematic error might be present in your experimental data?
What effect would these error sources have on your data?
Write out your answer in a clear and well supported paragraph.

erase this and type in your answer

2) In Parts A and B, does the precent difference between your measured weight in Data Studio
and the measured weight using the mass balance represent primarily measurement error, or is
there significant systematic error in your data? Explain how you make this determination.
Write out your answer in a clear and well supported paragraph.

erase this and type in your answer

3) In Part B, which value of weight (from the Digits display or Graph display) was closest to your
weight measured with the balance? Which of these two values would you expect to be more
accurate? Why? Write out your answer in a clear and well supported paragraph.

erase this and type in your answer

PS: that’s what i got so far with the lab i would like to continue from where i finished thanks and here they are :A. Smart Pulley B. Force Sensor

Table 2.1 Table 2.2
m1 (kg) 0.25000 W from Digits (N) W from Graph (N)
Uncert. – m1 0.00001
m2 (kg) 0.26000 -2.61 -2.61
Uncert. – m2 0.00001 -2.59 -2.6
a from Graph 1 (m/s/s) a from Graph 2 (m/s/s) -2.62 -2.61
-2.59 -2.61
-2.61 -2.61
0.168 0.17 -2.62 -2.61
0.166 0.17 -2.61 -2.61
0.158 0.16 -2.63 -2.61
0.157 0.16 -2.61 -2.61
0.156 0.16 -2.61 -2.61
0.164 0.16 Mean W – Digits -2.61
0.167 0.17
0.168 0.17 Std. Dev. – Digits #NAME?
0.166 0.17
0.167 0.17 Mean W – Graph -2.609
Mean a – Graph 1 0.164
Std. Dev. – Graph #NAME?
Std. Dev. – Graph 1 #NAME?
Meas. m – Mass Bal. 0.2645
Mean a – Graph 2 0.17
Uncert. – Meas. m
Std. Dev. – Graph 2 #NAME?
Calc. W – Mass Bal. 2.594745
Calc. g – Graph 1 -8.35
Uncert. – Calc. W
Uncert. – g – Graph 1
% Diff. – Digits
Calc. g – Graph 2 -8.5
% Diff. – Graph
Uncert. – g – Graph 2

% Error – Graph 1 15%

% Error – Graph 2 14%