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Table of contents
T
E
CBR
X
A
S
I
NS
T
R
U
)
M
E
)
N
T
)
S
I
NTRODUCTION
What is CBR? 2
Getting started with CBR — It’s as easy as 1, 2, 3 4
Hints for effective data collection 6
Activities with teacher notes and student activity sheets
TRIGGER
85-86
92
³
Activity 1 — Match the graph linear 13
³
Activity 2 — Toy car linear 17
³
Activity 3 — Pendulum sinusoidal 21
³
Activity 4 — Bouncing ball parabolic 25
³
Activity 5 — Rolling ball parabolic 29
Teacher information 33
Technical information
CBR data is stored in lists 37
RANGER settings 38
Using CBR with CBL or with CBL programs 39
Programming commands 40
statistics and data analysis: data collection methods, statistical analysis
0
What’s in this guide?
Getting Started with CBR
calculator or programming experience. It includes quick-start instructions for using
on effective data collection, and five classroom activities to explore basic functions and
properties of motion. The activities (see pages 13–32) include:
teacher notes for each activity, plus general teacher information
0
step-by-step instructions
0
a basic data collection activity appropriate for all levels
0
explorations that examine the data more closely, including what-if scenarios
0
suggestions for advanced topics appropriate for precalculus and calculus students
0
a reproducible student activity sheet with open-ended questions appropriate for a wide
0
range of grade levels
is designed to be a guide for teachers who don’t have extensive
, you’re just three simple steps from the first data sample!
CBR
Connect
Connect
using the calculator-to-
Push in
connection.
The short calculator-to-calculator
Note:
cable that comes with the calculator also
works.
to a TI graphing calculator
CBR
cable.
CBR
firmly
at both ends to make the
Transfer
RANGER
transfer the appropriate program from the
First, prepare the calculator to receive the program (see keystrokes below).
, a customized program for each calculator, is in the
to a calculator.
CBR
. It’s easy to
CBR
TI-82 or TI-83TI-85/CBL or TI-86TI-92
LINK
Ÿ
[
Next, open the pivoting head on the
program-transfer button on the
During transfer, the calculator displays
transfer is complete, the green light on
and the calculator screen displays
on
Once you’ve transferred the
won’t need to transfer it to that calculator again unless you delete it from
the calculator’s memory.
Note:
You may need to delete programs and data from the calculator. You can
save the programs and data first by transferring them to a computer using
TI-Graph Linké or to another calculator using a calculator-to-calculator cable
or the calculator-to-
flashes twice and
CBR
The program and data require approximately 17,500 bytes of memory.
For quick results, try
one of the classroomready activities in this
guide!
TI-82 or TI-83TI-85/
^
Press
Choose
Press
RANGER
›
.
.
.
^ A
Press
Choose
›
Press
or TI-86TI-92
CBL
RANGER
.
.
.
Press L [
Choose
Press ¨
VAR-LINK
RANGER
›
.
.
The opening screen is displayed.
Press
›. The
MAIN MENU
SETUPàSAMPLE
SET DEFAULTS
APPLICATIONS
PLOT MENU
TOOLS
QUIT
From the
Press
MAIN MENU
› to choose
MAIN MENU
&
&
&
&
&
choose
is displayed.
view/change the settings before sampling
change the settings to the default settings
DISTANCE MATCH, VELOCITY MATCH, BALL BOUNCE
plot options
GET CBR DATA, GET CALC DATA, STATUS, STOPàCLEAR
SET DEFAULTS
START NOW
. The
. Set up the activity, and then press › to
screen is displayed.
SETUP
begin data collection. It’s that easy!
Important information
0
This guide applies to all TI graphing calculators that can be used with
so you may find that some of the menu names do not match exactly those
on your calculator.
0
When setting up activities, ensure that the
is securely anchored and
CBR
that the cord cannot be tripped over.
0
Always exit the
RANGER
program performs a proper shutdown of
ensures that
0
Always disconnect
is properly initialized for the next time you use it.
Understanding how a sonic motion detector works can help you get better data plots. The
motion detector sends out an ultrasonic pulse and then measures how long it takes for that
pulse to return after bouncing off the closest object.
, like any sonic motion detector, measures the time interval between transmitting the
CBR
ultrasonic pulse and the first returned echo, but
much more. When the data is collected,
using a speed-of-sound calculation. Then it computes the first and second derivatives of
CBR
the distance data with respect to time to obtain velocity and acceleration data. It stores
these measurements in lists
L1, L2, L3
, and L4.
calculates the distance of the object from the
CBR
has a built-in microprocessor that does
CBR
Performing the same calculations as
Collect sample data in
➊
Use the sample times in
➋
REALTIME=NO
in conjunction with the distance data in L2 to calculate the
L1
is an interesting classroom activity.
CBR
mode. Exit the
RANGER
program.
velocity of the object at each sample time. Then compare the results to the velocity data
in
.
L3
(
+
L2
=
L3
n
Use the velocity data in L3 (or the student-calculated values) in conjunction with the
➌
sample times in
L1
n+1
to calculate the acceleration of the object at each sample time. Then
)à2 N (
L2
n
L1
n+1
N
compare the results to the acceleration data in
Object size
Using a small object at a far distance from the
+
L2
n
L1
n
decreases the chances of an accurate
CBR
L2
L4
n-1
.
)à2
reading. For example, at 5 meters, you are much more likely to detect a soccer ball than a
ping-pong ball.
Minimum range
When the
the
CBR.
be misidentified by
sends out a pulse, the pulse hits the object, bounces back, and is received by
CBR
If an object is closer than 0.5 meters (1.5 feet), consecutive pulses may overlap and
. The plot would be inaccurate, so position
CBR
at least 0.5 meters
CBR
away from the object.
Maximum range
As the pulse travels through the air, it loses its strength. After about 12 meters (6 meters on
the trip to the object and 6 meters on the trip back to the
weak to be reliably detected by the
the
G
ETTING STARTED WITH
6
. This limits the typical reliably effective distance from
beam is not a narrow, pencil-like beam, but fans out in all directions up
CBR
to 10° in a cone-shaped beam.
To avoid interference from other objects in the vicinity, try to establish a clear zone in the
path of the
recorded by
Reflective surfaces
beam. This helps ensure that objects other than the target do not get
CBR
CBR. CBR
records the closest object in the clear zone.
Some surfaces reflect pulses better than others. For example, you might see better results
with a relatively hard, smooth surfaced ball than with a tennis ball. Conversely, samples
taken in a room filled with hard, reflective surfaces are more likely to show stray data points.
Measurements of irregular surfaces (such as a toy car or a student holding a calculator while
walking) may appear uneven.
A Distance-Time plot of a nonmoving object may have small differences in the calculated
distance values. If any of these values map to a different pixel, the expected flat line may
show occasional blips. The Velocity-Time plot may appear even more jagged, because the
change in distance between any two points over time is, by definition, velocity. You may
wish to apply an appropriate degree of smoothing to the data.
program can reduce the effect of stray signals
or variations in the distance measurements. Avoid excessive smoothing. Begin with no
smoothing or
smoothing. Increase the degree of smoothing until you obtain
LIGHT
satisfactory results.
For an activity with a higher-than-average likelihood of stray signals, you may wish to
0
increase the smoothing on the
For already-collected
0
REALTIME=NO
calculator must be connected to the
choose
Noise—what is it and how do you get rid of it?
When the
SMOOTH DATA
receives signals reflected from objects other than the primary target, the plot
CBR
, and then choose the degree of smoothing.
screen before sampling (see page 38).
SETUP
data, you can apply smoothing to the data. The
. Choose
CBR
PLOT TOOLS
from the
PLOT MENU
,
shows erratic data points (noise spikes) that do not conform to the general pattern of the
plot. To minimize noise:
Make sure the
0
viewing a
REALTIME=NO
Try to sample in a clutter-free space (see the clear zone drawing on page 7).
0
Choose a larger, more reflective object or move the object closer to the
0
REALTIME=YES
is pointed directly at the target. Try adjusting the sensor head while
CBR
sample until you get good results before collecting a
sample.
CBR
(but farther
than 0.5 meters).
When using more than one
0
in a room, one group should complete a sample before
CBR
the next group begins their sample.
For a noisy
0
REALTIME=YES
obtain satisfactory results. (You cannot change the smoothing in the
VELOCITY MATCH
For a noisy
0
, or
REALTIME=NO
sample, repeat using a higher degree of smoothing until you
DISTANCE MATCH
BALL BOUNCE
applications.)
sample, you can apply a higher degree of smoothing to the
original data.
,
Speed of sound
The approximate distance to the object is calculated by assuming a nominal speed of sound.
However, actual speed of sound varies with several factors, most notably the air
temperature. For relative-motion activities, this factor is not important. For activities
requiring highly accurate measurements, a programming command can be used to specify
the ambient temperature (see pages 40–41).
when you need to collect or plot only one type of data (distance, velocity, or acceleration)
0
mode:
for a sample
In
REALTIME=YES
mode, the
processes the requested plot data (distance, velocity, or
CBR
acceleration), which is transferred to the calculator following each individual distance
measurement. Then
RANGER
plots a single pixel for that pulse.
Because all of these operations must be completed before the next sample can be
requested, the maximum rate at which data can be sampled in
REALTIME=YES
mode is
limited.
It takes approximately 0.080 seconds just to sample, process, and transfer the data for a
single data point. Additional time is required for operations such as plotting the point, which
slows the effective sample rate to approximately 0.125 seconds in
REALTIME=NO
Use
REALTIME=NO
for faster objects
0
when smoothing is required (see page 9)
0
to operate the
0
when you need to collect or plot all types of data (distance, velocity, and acceleration) for
0
mode:
in detached mode (see page 11)
CBR
RANGER
.
a sample
In
after all sampling is completed. The sample rate can be as fast as once every 0.005 seconds
for close objects. Data for time, distance, velocity, and acceleration is transferred to the
calculator.
Because the data is stored in the
and again.
0
0
0
G
ETTING STARTED WITH
10
REALTIME=NO
mode, data is stored in the
, you can transfer it from the
CBR
Each time you change smoothing, the
CBR
and not transferred to the calculator until
CBR
to a calculator again
CBR
applies the new smoothing factor, transfers
the adjusted data to the calculator, and stores the smoothed values in the lists.
Choosing a domain changes the lists stored in the calculator. If you need to, you can
recover the original data from the
choose
TOOLS
. From the
menu, choose
TOOLS
. From the
CBR
MAIN MENU
GET CBR DATA
in the
.
RANGER
program,
You also can share the same data with many students, even if they are using different
types of TI graphing calculators. This allows all students to participate in data analysis
activities using the same data (see page 11).
, you can explore the data in relationship
to a function. Because the data is collected as lists and displayed as a statistical plot, you can
use
, , and œ to explore this relationship.
Inside RANGER
Explore plots using
0
, which is set automatically. (On the TI-85, use the free-moving
TRACE
cursor.)
Manipulate the data set, including smoothing the data or selecting the domain of
0
interest.
Outside RANGER
Explore data using the calculator’s list editor.
0
Manually model a function to the data using the calculator’s Y= editor.
0
Automatically determine the equation that best fits the data using the calculator’s
0
regression capabilities.
Other relationships can be explored beyond those represented by the plot options in
RANGER
as statistical plots. From the
Plot1
. For instance, simultaneous plots of Distance-Time and Velocity-Time can be viewed
as L1 versus L2 and
MAIN MENU
as L1 versus L3. (You may also need to adjust the Window.)
Plot2
in the
RANGER
program, choose
, and then set
QUIT
Data and plots can be sent to a computer using TI-Graph Link. This is especially useful when
students generate more involved reports of their activity findings.
Using CBR without the RANGER program
You can use
For information on using
0
For information on obtaining programs and activities, see page 36.
0
For information on programming commands to write your own programs, see pages
Function explored: linear.
MATCH introduces the real-world concepts of distance
and time—or more precisely, the concept of distance
versus time. As students attempt to duplicate graphs
by walking while seeing their motion plotted, the
concept of position can be explored.
In Explorations, students are asked to convert their
rate of walking in meters per second to kilometers per
hours.
Once they have mastered the Distance-Time match,
challenge your students to a Velocity-Time match.
A TI ViewScreené allows other students to watch—
and provides much of the fun of this activity.
Hints
Students really enjoy this activity. Plan adequate time
because everybody will want to try it!
This activity works best when the student who is
walking (and the entire class) can view his or her
motion projected on a wall or screen using the TI
ViewScreen.
Typical answers
1. time (from start of sample); seconds; 1 second;
distance (from the CBR to the object); meters;
1 meter
2. the y-intercept represents the starting distance
3. varies by student
4. backward (increase the distance between the CBR
and the object)
5. forward (decrease the distance between the CBR
and the object)
6. stand still; zero slope requires no change in y
(distance)
7. varies by graph; @yà3.3
8. varies by graph; @yà1
9. the segment with the greatest slope (positive or
negative)
10. this is a trick question—the flat segment, because
you don’t move at all!
11. walking speed; when to change direction and/or
speed
12. speed (or velocity)
13. varies by graph (example: 1.5 meters in 3 seconds)
14. varies by graph; example: 0.5 metersà1 second
Guide the students to walk in-line with the CBR; they
sometimes try to walk sideways (perpendicular to the
line to the CBR) or even to jump up!
Instructions suggest that the activity be done in
meters, which matches the questions on the student
activity sheet.
See pages 6–12 for hints on effective data collection.
Typical plots
example: (0.5 meters à 1 second) Q (60 seconds à
1 minute) = 30 meters à minute
example: (30 meters à 1 minute) Q (60 minutes à 1
hour) = 1800 meters à hour
example: (1800 meters à 1 hour) Q (1 kilometer à
1000 meter) = .18 kilometers à hour.
Have students compare this last number to the
velocity of a vehicle, say 96 kilometers à hour
(60 miles per hour).
15. varies by graph; sum of the @y for each line
segment.
in one hand, and the calculator in the other. Aim the sensor directly at a
CBR
wall.
Hints:
The maximum distance of any graph is 4 meters (12 feet) from the
minimum range is 0.5 meters (1.5 feet). Make sure that there is nothing in the clearzone (see page 7).
CBR
. The
Run the
➋
➌
➍
From the
From the
RANGER
MAIN MENU
APPLICATIONS
displayed.
Press › to display the graph to match. Take a moment to study the graph. Answer
➎
program (see page 5 for keystrokes for each calculator).
choose
menu choose
DISTANCE MATCH
APPLICATIONS
automatically takes care of the settings.
. Choose
DISTANCE MATCH
METERS
.
. General instructions are
questions 1 and 2 on the activity sheet.
Position yourself where you think the graph begins. Press › to begin data collection.
➏
You can hear a clicking sound and see the green light as the data is collected.
Walk backward and forward, and try to match the graph. Your position is plotted on
➐
the screen.
When the sample is finished, examine how well your “walk” matched the graph, and
➑
then answer question 3.
Press › to display the
➒
OPTIONS
menu and choose
SAME MATCH
. Try to improve your
walking technique, and then answer questions 4, 5, and 6.
Function explored: linear.
The motion of a motorized toy car is used to illustrate
the real-world concept of constant velocity.
Materials
Ÿ calculator
Ÿ CBR
Ÿ calculator-to-CBR cable
Ÿ battery-operated toy car
Ÿ TI ViewScreen (optional)
Hints
Toy cars vary greatly in size, shape, and angle of
reflection of the incident ultrasonic sound. Therefore,
the resulting plots may vary in quality. Some vehicles
may require an additional reflective surface in order to
obtain good plots. Try mounting an index card to the
vehicle to assure a good target for the sensor.
You may wish to try a variety of vehicles so the
students can explore these effects.
Toy cars that are slower (such as those designed for
younger children) are better for this activity. Look for a
car that appears to keep a constant velocity.
See pages 6–12 for hints on effective data collection.
Explorations
The slope of an object’s Distance-Time plot at any time
gives the object’s speed at that time. Thus, for an
object traveling at constant velocity, the slope of its
Distance-Time plot is constant. This is why the
Distance-Time plot exhibits a linear relationship.
If you start collecting data before the car begins
moving, you will notice the Distance-Time plot is not
linear at the beginning of the plot. Why? The car
begins at rest (v = 0). It cannot instantaneously attain
its constant velocity. Acceleration is given by:
∆
v
a
=
∆
t
In order for the object to go instantaneously from rest
to its constant velocity, ∆t = 0. But this implies infinite
acceleration, which is not physically possible. (In fact,
by Newton’s Second Law, F = ma, an infinite
acceleration could only result from an infinite force,
which is equally impossible.) Thus we must observe the
object accelerating (increasing its speed) to its
constant velocity over a finite time period.
Typical plots
Answers to questions
1. the first or last plot; distance increases at constant
rate
2. students enter values from TRACE
3. distance values increase by a constant amount
4. velocity is rate of change for distance over time;
the values are the same for each equal time
increment
5. student should get a value similar to the values
calculated for m
similar to mm represents velocity or speed of car
6. b is the y-intercept; example: y = 2x + 0
7. varies; for example, if m = 2, distance (y) = 20
meters after 10 seconds (y = 2 Q 10 + 0); for 1
minute, y = 120 meters
Advanced Explorations
The slope of a Velocity-Time plot for constant velocity
is zero. Therefore, the Acceleration-Time plot shows
a = 0 (in the ideal case) over the time period where
velocity is constant.
The resulting area is the object’s displacement (net
distance traveled) during the time interval t
For calculus students, the displacement can be found
from:
t
2
=
svdt
∫
t
1
where s is the object’s displacement in the interval t
to t2.
The values for x (time) in half-second intervals are in the first column in question 2.
➊
Trace the plot and enter the corresponding y (distance) values in the second
column.
disregard inconsistent data at the beginning of the data collection. Also, you may need
to approximate the distance (the calculator may give you distance for 0.957 and 1.01
seconds instead of exactly 1 second). Pick the closest one or take your best guess.
➋
Answerquestions 3 and 4.
Calculate the changes in distance and time between each data point to complete the
➌
third and fourth columns. For example, to calculate @Distance (meters) for 1.5 seconds,
subtract Distance at 1 second from Distance at 1.5 seconds.
The function illustrated by this activity is y = mx + b. m is the slope of a line. It is
➍
calculated by:
Include results only from the linear part of the plot. You may need to
Note:
(cont.)linear
The y-intercept represents b.
Calculate m for every point. Enter the values in the table in question 2.
➎
Answer questions 5, 6, and 7.
Advanced Explorations
Calculating the slope of a Distance-Time plot at any time gives the object’s approximate
velocity at that time. Calculating the slope of a Velocity-Time plot gives the object’s
approximate acceleration at that time. If velocity is constant, what does acceleration equal?
Predict what the Acceleration-Time plot for this Distance-Time plot looks like.
Find the area between the Velocity-Time plot and the x-axis between any two convenient
times, t
and t2. This can be done by summing the areas of one or more rectangles, each
1
with an area given by:
What is the physical significance of the resulting area?
See pages 6–12 for hints on effective data collection.
Physical connections
An object that undergoes periodic motion resulting
from a restoring force proportional to its displacement
from its equilibrium (rest) position is said to exhibit
simple harmonic motion (SHM). SHM can be described
by two quantities.
0
The period T is the time for one complete cycle.
0
The amplitude A is the maximum displacement of
the object from its equilibrium position (the position
of the weight when at rest).
For a simple pendulum, the period T is given by:
L
= 2p
T
where L is the string length and g is the magnitude of
the acceleration due to gravity. T does not depend on
the mass of the object or the amplitude of its motion
(for small angles).
The frequency f (number of complete cycles per
second) can be found from:
1
f =
, where f is in hertz (Hz) when T is in seconds.
T
The derivatives of a sinusoidal plot are also sinusoidal.
Note particularly the phase relationship between the
weight’s position and velocity.
g
Typical plots
Typical answers
1. varies (in meters)
2. varies (in meters)
3. varies (in seconds); T (one period) = total time of
10 periodsà10; averaging over a larger sample
tends to minimize inherent measurement errors
4. the total arc length, which should be
approximately 4 times the answer to question 2;
because an arc is longer than a straight line
5. sinusoidal, repetitive, periodic; distance from the xaxis to the equilibrium position
6. each cycle is spread out horizontally; a plot
spanning 10 seconds must fit more cycles in same
amount of screen space, therefore cycles appear
closer together
7. (total # of cycles)à(5 seconds) = cyclesàsecond;
easier to view full cycles, and fewer measurement
errors
8. f = 1àT, where T is time for 1 period
9. decreased period; increased period
(Pendulum length is directly related to period time;
the longer the string, the longer the period.
Students can explore this relationship using the
calculator’s list editor, where they can calculate the
period for various values of L.)
10. A (amplitude) = ¼ total distance that the
pendulum travels in 1 period
11. both sinusoidal; differences are in amplitude and
phase
12. equilibrium position
13. when position = maximum or minimum value
(when the weight is at greatest distance from
equilibrium).
14. It doesn’t. T depends only on L and g, not mass.
Advanced explorations
Data collection: the plot of L2 versus L3 forms an
ellipse.
to 5 seconds. Repeat the data collection. Observe the plot. Answer questions 6 and 7.
The quantity you determined (cycles per second) is called the frequency. Although you
calculated frequency in question 7 using the plot, you can find it mathematically from:
1
where T is the period in seconds, and f is the frequency in hertz (Hz).
f =
T
Answer question 8.
Data collections 3 and 4
Repeat the 5-second data collection two more times. First, shorten the string. Second,
lengthen the string. After observing those plots, answer question 9.
Another important distance measurement affecting the motion of the pendulum is the
amplitude. The answer to question 2 was the amplitude of that pendulum swing. Answer
question 10.
Advanced explorations
Data collection 5
From the
PLOT MENU
choose
choose
SETUPàSAMPLE
VELOCITY-TIME
. On the
screen, change the time from 10
SETUP
. Answer questions 11, 12 and 13.
Data collection 6
Repeat the data collection with a significantly lighter or heavier weight, and then answer
question 14.
Model the distance-time behavior of the pendulum using the form for a sinusoidal function,
S = A sin (wt +
frequency,
d
T, by w = 2
), where S is the instantaneous position, A is the amplitude, w is the
d
is the phase angle, and t is the time. The frequency, w, is related to the period,
T.
pà
Enter this equation in the Y= editor using the calculated values of A and w. Simultaneously
graph this function and the statistical plot of
of A, w, and
until a good fit is obtained. On the TI-83 or TI-86, use the sine regression to
d
(time) versus L2 (distance). Adjust the values
L1
determine the values.
Explore the relationship between position and velocity by plotting
(distance) versus
L2
L3
(velocity). What do you predict for the appearance of the resulting plot? Compare the actual
result to your prediction.
Using data collected from your plot, calculate the number of complete cycles per second. ________
7.
Why is it easier to determine this using the second plot (spanning 5 seconds) rather than the first
one (spanning 10 seconds)?_____________________________________________________________
Calculate the frequency for one period using the equation. __________________________________
8.
How does shortening the string length affect the period of the pendulum?_____________________
9.
How does lengthening the string affect the period of the pendulum?
. What is the relationship between the amplitude of the pendulum swing and the total distance that
10
__________________________
the pendulum travels in one period? _____________________________________________________
Function explored: parabolic.
Real-world concepts such as free-falling and bouncing
objects, gravity, and constant acceleration are
examples of parabolic functions. This activity
investigates the values of height, time, and the
coefficient A in the quadratic equation,
Y = A(X – H)
2
+ K, which describes the behavior of a
bouncing ball.
Materials
Ÿ calculator
Ÿ CBR
Ÿ calculator-to-CBR cable
Ÿ large (9-inch) playground ball
Ÿ TI ViewScreen (optional)
Hints
This activity is best performed with two students, one
to hold the ball and the other to push ¤.
See pages 6–12 for hints on effective data collection.
The plot should look like a bouncing ball. If it does
CBR
not, repeat the sample, ensuring that the
is aimed
squarely at the ball. A large ball is recommended.
Typical plots
3. The Distance-Time plot for this activity does not
CBR
represent the distance from the
BALL BOUNCE
flips the distance data so the plot
to the ball.
better matches students’ perceptions of the ball’s
behavior. y = 0 on the plot is actually the point at
which the ball is farthest from the
CBR
, when the
ball hits the floor.
4. Students should realize that the x-axis represents
time, not horizontal distance.
7. The graph for A = 1 is both inverted and broader
than the plot.
8. A < L1
9. parabola concave up; concave down; linear
12. same; mathematically, the coefficient A represents
the extent of curvature of the parabola; physically,
A depends upon the acceleration due to gravity,
which remains constant through all the bounces.
Advanced explorations
The rebound height of the ball (maximum height for a
given bounce) is approximated by:
x
y = hp
0
y is the rebound height
0
h is the height from which the ball is released
0
p is a constant that depends on physical
characteristics of the ball and the floor surface
0
x is the bounce number
, where
Explorations
After an object is released, it is acted upon only by
gravity (neglecting air resistance). So A depends on the
acceleration due to gravity, N9.8 metersàsecond
2
(N32 feetàsecond2). The negative sign indicates that
the acceleration is downward.
The value for A is approximately one-half the
acceleration due to gravity, or N4.9 metersàsecond
2
(N16 feetàsecond2).
Typical answers
1. time (from start of sample); seconds; height à
distance of the ball above the floor; meters or feet
2. initial height of the ball above the floor (the peaks
represent the maximum height of each bounce);
the floor is represented by y = 0.
For a given ball and initial height, the rebound height
decreases exponentially for each successive bounce.
When x = 0, y = h, so the y-intercept represents the
initial release height.
Ambitious students can find the coefficients in this
equation using the collected data. Repeat the activity
for different initial heights or with a different ball or
floor surface.
After manually fitting the curve, students can use
regression analysis to find the function that best
models the data. Select a single bounce using
TOOLS
SELECT DOMAIN
,
. Then
QUIT
from the
PLOT
MAIN MENU
Follow the calculator operating procedures to perform
a quadratic regression on lists
L1
and L2.
Extensions
Integrate under Velocity-Time plot, giving the
displacement (net distance traveled) for any chosen
time interval. Note the displacement is zero for any full
bounce (ball starts and finishes on floor).
Begin with a test bounce. Drop the ball (do not throw it).
➊
Hints:
Position the
at least 0.5 meters (1.5 feet) above the height of the highest
CBR
bounce. Hold the sensor directly over the ball and make sure that there is nothing in the
clear zone (see page 7).
Run the
➋
From the
➌
From the
➍
BALL BOUNCE
RANGER
MAIN MENU
APPLICATIONS
program (see page 5 for keystrokes for each calculator).
choose
APPLICATIONS
menu choose
. Choose
BALL BOUNCE
METERS
or
FEET
. General instructions are displayed.
automatically takes care of the settings.
.
➎
➏
➐
➑
G
ETTING STARTED WITH
26
Hold the ball with arms extended. Press ›. The
mode. At this point, you may detach
from the calculator.
CBR
RANGER
program is now in Trigger
Press ¤. When the green light begins flashing, release the ball, and then step
back. (If the ball bounces to the side, move to keep the
be careful
to change the height of the
not
CBR
.)
directly above the ball, but
CBR
You can hear a clicking sound as the data is collected. Data is collected for time and
distance, and calculated for velocity and acceleration. If you have detached the
CBR
,
reattach it when data collection is finished.
Press ›. (If the plot doesn’t look good, repeat the sample.) Study the plot. Answer
Function explored: parabolic.
Plotting a ball rolling down a ramp of varying
inclines creates a family of curves, which can be
modeled by a series of quadratic equations. This
activity investigates the values of the coefficients in
the quadratic equation, y = ax
2
+ bx + c.
Materials
Ÿ calculator
Ÿ CBR
Ÿ calculator-to-CBR cable
Ÿ mounting clamp
Ÿ large (9 inch) playground ball
Ÿ long ramp (at least 2 meters or 6 feet—a
lightweight board works well)
Ÿ protractor to measure angles
Ÿ books to prop up ramp
Ÿ TI ViewScreen (optional)
Hints
Discuss how to measure the angle of the ramp. Let
students get creative here. They might use a
trigonometric calculation, folded paper, or a
protractor.
See pages 6–12 for hints on effective data
collection.
Typical plots
15
¡
30
¡
Typical answers
1. the third plot
2. time; seconds; distance of object from CBR; feet
or meters
3. varies (should be half of a parabola, concave
up)
4. a parabola (quadratic)
5. varies
6. varies (should be parabolic with increasing
curvature)
7. 0¡ is flat (ball can’t roll); 90¡ is the same as a
free-falling (dropping) ball
Explorations
The motion of a body acted upon only by gravity is
a popular topic in a study of physical sciences. Such
motion is typically expressed by a particular form of
the quadratic equation,
s = ½at
0
0
0
0
In the quadratic equation y = ax
y represents the distance from the
2
+ vit + si where
s is the position of an object at time t
a is its acceleration
vi is its initial velocity
si is its initial position
2
+ bx + c,
CBR
to the ball
at time x if the ball’s initial position was c, initial
velocity was b, and acceleration is 2a.
Advanced explorations:
Since the ball is at rest when released, b should
approach zero for each trial. c should approach the
initial distance, 0.5 meters (1.5 feet). a increases as
the angle of inclination increases.
If students model the equation y = ax
manually, you may need to provide hints for the
values of b and c. You may also direct them to
perform a quadratic regression on lists
their calculators. The ball’s acceleration is due to
the earth’s gravity. So the more the ramp points
down (the greater the angle of inclination), the
greater the value of a. Maximum a occurs for
q = 90¡, minimum for q = 0¡. In fact, a is
proportional to the sine of q.
Answer question 1 on the activity sheet. Set the ramp at a 15° incline. Attach the
clamp to the top edge of the ramp. Attach the
and position it perpendicular to the ramp. Attach the calculator to the
to the clamp. Open the sensor head
CBR
.
CBR
Mark a spot on the ramp 0.5 meters (1.5 feet) from the
ball at this mark, while a second student holds the calculator.
Hints:
Aim the sensor directly at the ball and make sure that there is nothing in the
clear zone (see page 7).
Run the
➋
MENU
Press › to display the settings. For this activity, they should be:
➌
SMOOTHING:LIGHT
RANGER
choose
REALTIME:NO
TIME (S):3 SECONDS
DISPLAY:DISTANCE
BEGIN ON:[ENTER]
UNITS:METERS
program (see page 5 for keystrokes for each calculator). From the
SETUPàSAMPLE
.
. Have one student hold the
CBR
MAIN
➍
➎
➏
➐
G
ETTING STARTED WITH
30
Instructions for changing a setting are on page 38.
When the settings are correct, choose
START NOW
. Press › to begin sampling.
When the clicking begins, release the ball immediately (don’t push) and step back.
When the sample is complete, the Distance-Time plot is displayed automatically.
Answer questions 2 and 3.
Press › to display the
DOMAIN
. Move the cursor to where the ball was released, and then press ›. Move
PLOT MENU
the cursor to where the ball reached the end of the ramp, and then press
. Choose
PLOT TOOLS
, and then choose
›. The
SELECT
plot is redrawn, focusing on the portion of the sample that corresponds to the ball
rolling down the ramp. Answer questions 4 and 5.
Predict what will happen if the incline increases. Answer question 6.
➊
Adjust the incline to 30¡. Repeat steps 2 through 6. Add this plot to the drawing in
➋
question 6, labeled 30¡.
Repeat steps 2 through 6 for inclines of 45¡ and 60¡ and add to the drawing.
➌
➍
Answer question 7.
Advanced explorations
Adjust the time values so that x = 0 for the initial height (the time at which the ball was
released. You can do this manually by subtracting the x value for the first point from all the
points on your plot, or you can enter
(cont.)
L1(1)"A:L1NA"L1
parabolic
.
Calculate the values for a, b, and c for the family of curves in the form y = ax
➊
at 0¡, 15¡, 30¡, 45¡, 60¡, 90¡.
What are the minimum and maximum values for a? Why?
➋
Write an expression describing the mathematical relationship between a and the angle
is an easy-to-use system with features that help you integrate it into your lesson plans
CBR
quickly and easily.
offers significant improvements over other data-collection methods you may have used
CBR
in the past. This, in turn, may lead to a restructuring of how you use class time, as your
students become more enthusiastic about using real-world data.
You’ll find that your students feel a greater sense of ownership of the data because they
0
actually participate in the data-collection process rather than using data from textbooks,
periodicals, or statistical abstracts. This impresses upon them that the concepts you
explore in class are connected to the real world and aren’t just abstract ideas. But it also
means that each student will want to take his or her turn at collecting the data.
Data collection with
0
is considerably more effective than creating scenarios and
CBR
manually taking measurements with a ruler and stopwatch. Since more sampling points
give greater resolution and since a sonic motion detector is highly accurate, the shape of
curves is more readily apparent. You will need less time for data collection and have more
time for analysis and exploration.
0
With
students can explore the repeatability of observations and variations in what-if
CBR
scenarios. Such questions as “Is it the same parabola if we drop the ball from a greater
height?” and “Is the parabola the same for the first bounce as the last bounce?” become
natural and valuable extensions.
The power of visualization lets students quickly associate the plotted list data with the
0
physical properties and mathematical functions the data describes.
Other changes occur once the data from real-world events is collected.
lets your
CBR
students explore underlying relationships both numerically and graphically.
Explore data graphically
Use automatically generated plots of distance, velocity, and acceleration with respect to time
for explorations such as:
What is the physical significance of the y-intercept? the x-intercept? the slope? the
0
maximum? the minimum? the derivatives? the integrals?
How do we recognize the function (linear, parabolic, etc.) represented by the plot?
0
How would we model the data with a representative function? What is the significance of
0
the various coefficients in the function (e.g., AX
Explore data numerically
Your students can employ statistical methods (mean, median, mode, standard deviation,
etc.) appropriate for their level to explore the numeric data. When you exit the
program, a prompt reminds you of the lists in which
velocity, and acceleration is stored.
CBR plots—connecting the physical world and mathematics
The plots created from the data collected by
RANGER
are a visual representation of the
relationships between the physical and mathematical descriptions of motion. Students
should be encouraged to recognize, analyze, and discuss the shape of the plot in both
physical and mathematical terms. Additional dialog and discoveries are possible when
functions are entered in the Y= editor and displayed with the data plots.
A Distance-Time plot represents the approximate position of an object (distance from the
0
) at each instant in time when a sample is collected. y-axis units are meters or feet;
CBR
x-axis units are seconds.
A Velocity-Time plot represents the approximate speed of an object (relative to, and in the
0
direction of, the
) at each sample time. y-axis units are metersàsecond or feetàsecond;
CBR
x-axis units are seconds.
An Acceleration-Time plot represents the approximate rate of change in speed of an
0
object (relative to, and in the direction of, the
metersàsecond
The first derivative (instantaneous slope) at any point on the Distance-Time plot is the
0
2
or feetàsecond2; x-axis units are seconds.
) at each sample time. y-axis units are
CBR
speed at that instant.
The first derivative (instantaneous slope) at any point on the Velocity-Time plot is the
0
acceleration at that instant. This is also the second derivative at any point on the DistanceTime plot.
A definite integral (area between the plot and the x-axis between any two points) on the
0
Velocity-Time plot equals the displacement (net distance traveled) by the object during
that time interval.
0
Speed and velocity are often used interchangeably. They are different, though related,
properties. Speed is a scalar quantity; it has magnitude but no specified direction, as in “6
feet per second.” Velocity is a vector quantity; it has a specified direction as well as
magnitude, as in “6 feet per second due North.”
A typical
Velocity-Time plot actually represents speed, not velocity. Only the
CBR
magnitude (which can be positive, negative, or zero) is given. Direction is only implied. A
positive velocity value indicates movement away from the
movement toward the
measures distance only along a line from the detector. Thus, if an object is moving at
CBR
CBR
.
; a negative value indicates
CBR
an angle to the line, it only computes the component of velocity parallel to this line. For
example, an object moving perpendicular to the line from the
an activities page with applications developed and shared by teachers like you
0
programs that access additional
0
CBR
more detailed information about
0
Additional resources
Texas Instruments’ Explorations books provide supplemental material related to TI graphing
calculators, including books with classroom activities for
and high-school math and science classes.
collects data, it automatically transfers it to the calculator and stores the data in
CBR
lists. Each time you exit the
contains time data.
0
L1
contains distance data.
0
L2
contains velocity data.
0
L3
contains acceleration data.
0
L4
For example, the 5th element in list
collected, and the 5th element in list
In
REALTIME=YES
, only the data for the requested plot (distance, velocity, or acceleration) is
calculated and transferred. In
Settings are stored in list L5
The
RANGER SETUP
screen makes it easy to change the most commonly-used
(see page 38).
When you transfer the
new list containing the defaults.
See pages 40–41 for information about programming commands that change other
settings.
RANGER
RANGER
program, you are reminded of where the data is stored.
represents the time when the 5th data point was
L1
represents the distance of the 5th data point.
L2
REALTIME=NO
program from the
, all the data is calculated and transferred.
CBR
CBR, L5
is automatically replaced with a
parameters
Using the data lists
The lists are not deleted when you exit the
additional graphical, statistical, and numerical explorations and analyses.
You can plot the lists against each other, display them in the list editor, use regression
analysis, and perform other analytical activities. For example, you could collect the data from
pendulum motion using
explore elliptical functions. (You may also need to adjust the Window.)
displays the most commonly used settings before data collection begins.
From the
MAIN MENU
in the
RANGER
program, choose
SETUPàSAMPLE
settings are shown. 4 indicates the location of the cursor.
MAIN MENU
REALTIME: & YES
TIME (S):
DISPLAY: & DISTANCE, VELOCITY
BEGIN ON:
SMOOTHING:
Press c or b to move to the setting you want to change.
➋
Press
➌
›
to move to the next option. To change
.
b
When all the settings are correct, press c or b until the cursor is on
➍
To continue, press
0
To return to the
0
The new settings remain unless you choose
program that changes the settings. If you manipulate
delete
, the default settings may be restored the next time you run
L5
START NOW
or
NO
UNITS:
& TOTAL TIME
= 1–99
& [ENTER], [TRIGGER],
& NONE
& METERS
,
LIGHT, MEDIUM
or
FEET
SECONDS
, or
ACCELERATION
or
10-SECOND DELAY
, or
HEAVY
(
to cycle through the available options. When the option is correct, press
, enter 1 or 2 digits, and then press c or
TIME
.
›
MAIN MENU
, press e, and then press
SET DEFAULTS
L5
›
, run an application, or run another
outside the
. The current
REALTIME=NO
START NOW
.
RANGER
RANGER
)
only
.
program or
.
c
Restoring RANGER settings to the defaults
The default settings are appropriate for a wide variety of sampling situations. If you are
unsure of the best settings, begin with the default settings, and then adjust.
➊
From the
MAIN MENU
in the
RANGER
The settings are changed to the defaults and the
If you wish to change a setting from the default, follow the steps above.
➋
To continue, press
➌
when cursor is on
›
Other RANGER settings
The
RANGER
program accesses the most commonly changed settings.
settings. See pages 40–41 for information about programming commands that change
these settings.
0 (default)Disables temperature compensation.
1Enables temperature compensation.
Command 2 Data setup {2,
data_typeResults
1 (default)List
Command 3Sample/Trigger {3,
sample_timeResults
0.005–1500 (0.1)Time in seconds between each sample
0.0001–0.005Rounds to 0.005.
1500<x<16000Rounds to 1500.
sample#Results
L1Selects
REALTIME=NO
1–512 (
triggerResults
0Begins sampling with no trigger.
1 (default)Begins sampling on ¤.
7Delays 10 seconds, then begins sampling.
record_timeResults
0 (default)None
REALTIME=NO
1(
REALTIME=NO
2(
filter (see command 1, operation field)Results
0 (default)No filtering
REALTIME=NO
1 (
REALTIME=NO
2 (
REALTIME=NO
3 (
REALTIME=NO
4 (
REALTIME=NO
5 (
REALTIME=NO
6 (
REALTIME=YES
7 (
REALTIME=YES
8 (
REALTIME=YES
9 (
)Takes from 1 to 512 samples.
)Absolute time (starts at time 0, then adjusts sample time)
)Relative time (starts at time 0, then adjusts sample time)
)5 point Savitzsky-Golay smoothing
)9 point Savitzsky-Golay smoothing
)17 point Savitzsky-Golay smoothing
)29 point Savitzsky-Golay smoothing
)3 point median pruning filter
)5 point median pruning filter
0(default)Clears all equations.
4Designates equation 4.
equation_typeResults
0(default)Clears equation.
13Designates temperature compensation.
temperatureResults
floating-point numberSets current temperature.
unitsResults
0(default)None (ignored by
1Sets degrees = Fahrenheit.
2Sets degrees = Celsius.
3Sets degrees = Kelvin.
4Sets degrees = Rankin where R = F + 459.7.
Command 5 (
REALTIME=NO
first_channelResults
0(default)Selects lowest active channel.
1, 2, 3, 11, 21Specifies sonic channel.
M1Records time list.
data_selectResults
0Smoothed data {distance}
1Smoothed dàdt data {velocity}
2Smoothed d
3Raw data {distance}
4Raw dàdt data {velocity}
5Raw d
data_beginResults
1–512First data element for GET
data_endResults
0–512Last data element for GET (0 = last sample)
) Data range setup{5,
Command 6Systems options{6,
system_commandResults
0Stops sampling (for CBL compatibility).
2 (default)Stops sampling.
3Turns sound off (sound is on at power on).
4Turns sound on (sound is on at power on).
5Sets ID Number (operation required).
6Applies new filter to previous data (operation required).
operationResults
floating-point number ID_Number of form n.nnnnn (system_command = 5)
0–6New filter for previously collected data (system_command = 6)
Command 7Request status{7}
Returns a list containing:
10.rrrrDeviceCode.RomVersion
0–99Last error code (0 = no error)
0–2Battery condition (0 = OK; 1 = low during samples; 2 = always low)
11Sonic-channel identifier
sample_timeCurrent sample interval in seconds
trigger_conditionCurrent triggering option in use
functionCurrent channel function (1–9)
post_processingCurrent post-processing option (0–2)
filterCurrent filtering level (0–9)
samples# of samples available; 0–512
recorded_timeRecorded time option (0–2)
temperatureTemperature in use (¡C)
piezo_flag0 = sound off; 1 = sound on
system_state1 = not setup; 2 = armed; 3 = triggered/sampling; 4 = done
window_start0 = no command 5 yet; 1–512
window_end0 = use # of elements; 1–512
id_number6 digit ID # (default 0.00000) set by command 6 (system_command = 5)
Difficulty transferring the
program or collecting data
RANGER
Check for a poor calculator-toends of the cable.
CBR
connection. Always push in
firmly
Check for low batteries (see page 42).
CBR
begins collecting data by
itself
CBR
doesn’t quit collecting dataPress ¤ to stop sampling. Repeat sample. If problem continues, check
If you set down the CBR with the ¤ button face down, the ¤ button
may depress and activate sampling. Press ¤ again to stop sampling.
Before storing the
CBR
CBL
other
or
CBR,
properly exit the
program.
RANGER
program (using
QUIT)
program code.
LINK ERROR
messageAttach the
Check for a poor calculator-to-
CBR
to the calculator with the calculator-to-
CBR
connection. Always push in
CBR
cable.
firmly
ends of the cable.
If you do not want to (or cannot) attach the
break out of the
program, and then choose
Insufficient memoryYou must have sufficient memory for the
CBR
to the calculator, press ½
QUIT
.
RANGER
program and the data lists. The
programs and lists require approximately 17,500 bytes. Delete programs and/or
data.
Calculator doesn’t match activity
instructions
This guide applies to all the TI calculators that can be used with
find that some of the menu names, screens, or keys in this guide do not match
CBR
exactly those on your calculator. Choose the closest match. For example, if the
Data doesn’t look right:
0
points not on the curve
0
jagged plots
0
flat plots
0
broken plot
instructions say “Choose
MATCH
.
DISTANCE MATCH
Repeat the sample, ensuring that the CBR is aimed directly at the object.
Read pages 6–12 on getting good data samples.
Check that the clear zone does not contain students, tables, or other objects.
When using two
CBR
units at the same time in the same room, one group should
complete a sample before the next group begins their sample.
Check for a poor calculator-to-
CBR
connection. Always push in
,” on the TI-83 you would choose
firmly
ends of the cable.
Check for low batteries (see page 42).
Check that the degree of smoothing is not too much or too little.
CBR
won’t work with a TI-85Check to see that “
the calculator to indicate compatibility with
CBL
” appears at the end of the serial number on the back of
CBL
and
CBR
.
The TI-85 does not have statistical plotting capabilities, so some explorations (such
as using on plotted data) are not possible on the TI-85.
Lost calculator-to-
CBR
cableYou can use the calculator-to-calculator cable that came with the calculator. (The
calculator-to-calculator cable is much shorter, so you may wish to order a
replacement cable.)
Frequently low batteriesBefore storing the
CBR
CBL
or
program, and disconnect
When you try to run the
RANGER
program, nothing happens
Error message: Variable is locked
other
If you edit or view the
to two minutes for the calculator to prepare the program to run. This is normal.
You must unlock the variables L1, L2, L3, L4, and L5. See the calculator manual.
Call the Programming Assistance Group of Customer Support:
1.972.917.8324
For service information
Always contact Texas Instruments Customer Support before returning a product for service.
Customer support hours
8:00AM–4:30PM CST on Monday–Thursday and 9:30AM–4:30PM CST on Friday.
For more information about TI products and services, contact TI by e-mail or visit the TI
calculator home page on the World Wide Web.
ti-cares@ti.com
http://www.ti.com/calc
TI one-year limited warranty
This Texas Instruments electronic product warranty extends only to the original purchaser and user of the product.
Warranty Duration.
original purchase date.
Warranty Coverage.
warranty is void if the product has been damaged by accident or unreasonable use, neglect, improper service, or
other causes not arising out of defects in materials or construction.
Warranty Disclaimers. Any implied warranties arising out of this sale, including but not limited to the implied
warranties of merchantability and fitness for a particular purpose, are limited in duration to the above one-year
period. Texas Instruments shall not be liable for loss of use of the product or other incidental or consequential
costs, expenses, or damages incurred by the consumer or any other user.
Some states/provinces do not allow the exclusion or limitation of implied warranties or consequential damages, so the above
limitations or exclusions may not apply to you.
Legal Remedies.
or province to province.
Warranty Performance.
replaced with a reconditioned model of an equivalent quality (at TI’s option) when the product is returned, postage prepaid, to
Texas Instruments Service Facility. The warranty of the repaired or replacement unit will continue for the warranty of the
original unit or six (6) months, whichever is longer. Other than the postage requirement, no charge will be made for such repair
and/or replacement. TI strongly recommends that you insure the product for value prior to mailing.
This product is warranted to the original consumer purchaser for a period of one (1) year from the
This Texas Instruments electronic product is warranted against defective materials and construction.
This warranty gives you specific legal rights, and you may also have other rights that vary from state to state
During the above one (1) year warranty period, your defective product will be either repaired or
FCC information concerning radio frequency interference
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC
rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This
equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the
instructions, may cause harmful interference with radio communications. However, there is no guarantee that interference will
not occur in a particular installation.
If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the
equipment off and on, you can try to correct the interference by one or more of the following measures:
0
Reorient or relocate the receiving antenna.
0
Increase the separation between the equipment and receiver.
0
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
0
Consult the dealer or an experienced radio/television technician for help.
Caution
: Any changes or modifications to this equipment not expressly approved by Texas Instruments may void your authority