Lab #1: Introduction to Velocity - NNM-Science

Lab #1: Introduction to Velocity
Velocity is a rate. It tells us how much distance is covered in a unit of time. Velocity also includes a
direction for that motion, though we will not focus on direction for these labs. Velocity can be expressed by the formula:
v = d/t
where v = velocity or speed (in m/s), d = distance traveled (in meters), and t = time (in sec). In this activity, you will study
the velocity of a car released from different points on a ramp.
OBJECTIVES
In this experiment, you will:
• Develop a hypothesis about the relationship between release point and velocity.
• Use a single photogate to measure velocity.
• Evaluate data and write a conclusion using data collected during the lab.
• Generate a list of variables that could affect velocity.
PROCEDURE
1. Open the file “1-Velocity” from the Apps server in the Science/Logger Pro folder.
2. Confirm that the height of the photogate above the track is correct so that the photogate is unblocked (light off) as it
is positioned above the track, but will give one “block/unblock” event when a car travels through.
3. Measure the length of your car in centimeters, and convert it to meters. Enter that number in Logger Pro in the box
that says “CarLength.”
4. Place your car on the ramp with its front at the 60 cm line (30 cm from the gate). Click and release the car.
Do not press the stop button. Simply continue collecting data.
5. Record the velocity in your data table.
6. Repeat Steps 4 and 5 four more times.
7. Repeat Steps 4-6 with the car being released from the 80 cm and 100 cm positions (50 and 70 cm from the gate)
8. Calculate the averages for each release position.
PRE-LAB QUESTIONS
Manipulated variable: ___________________________ Responding variable: ______________________
Controlled variables (2): ___________________________________________________________________
Hypothesis:
4 Books
Wooden board with hot
wheels track attached.
There are marks at 5 cm
intervals.
Photogate set up at
the 30 cm mark
If ____________________________________________________________________________________________, then
__________________________________________________________________________________________, because
__________________________________________________________________________________________________________.
Labs 1&3 Adapted from Physical Science with Computers by Vernier
Lab 4 Adapted from Adapted from http://teacher.pas.rochester.edu/PhyInq/Experiments/P03/P03_Average_Speed.html Page 1

DATA
VELOCITY (M/S)
TRIAL # 60 CM (30 CM FROM GATE) 80 CM (50 CM FROM GATE) 100 CM (70 CM FROM GATE)
1
2
3
4
5
AVERAGE
PROCESSING THE DATA (SEPARATE PIECE OF PAPER, PLEASE!)
1. Print your graph and draw a line of best fit through your data points.
2. Velocity is calculated by determining how much distance is covered in a certain period of time. What distance did
Logger Pro use? What time? Draw a labeled picture or explain. Be careful on this one!
3. What happened to velocity as you released the car from higher points?
4. Did you have any outliers? If so, what is your explanation for why they exist?
5. What was the extra validity measure in this investigation?
6. List 3 other variables that you think might change how quickly the car travels down the ramp (not release point).
7. Write a conclusion for this lab.
Lab #2: Velocity Inquiry
In lab #1, you identified 3 variables that could affect the velocity of the car. You will now pick one
of those variables and write a procedure to test your hypothesis about that particular variable.
OBJECTIVES:
In this investigation, you will:
* Develop a hypothesis about a manipulated variable of your choice.
* Write a procedure and conduct an investigation.
* Analyze data and write a conclusion about your experiment.
* Use a single photogate as you did in Lab #1 to measure velocity.
Manipulated variable: ___________________________ Responding variable: ______________________
Controlled variables (2): ___________________________________________________________________
Hypothesis: If __________________________________________________________________________________, then
__________________________________________________________________________________________, because
__________________________________________________________________________________________________.
� The variables and hypothesis have been checked by your teacher.
Write a procedure on a piece of notebook paper that includes: logical steps, 2 controlled variables, 3 conditions of the
manipulated variable, what you are measuring and how often (responding variable), recording the data, multiple trials,
an extra validity measure, and an experimental control.
� The procedure has been checked by your teacher. Use the “2-Inquiry” file on the App$ server in the Science/Logger
Pro folder. Consider printing your graph for your lab report, due _______________________.
Labs 1&3 Adapted from Physical Science with Computers by Vernier
Lab 4 Adapted from Adapted from http://teacher.pas.rochester.edu/PhyInq/Experiments/P03/P03_Average_Speed.html Page 2

Lab #3: It’s Race Day
Air resistance, mass and friction are some factors that influence the speed of a Hot Wheels car. In
this contest, you will use principles you have learned in science as you race a car down a ramp. The
fastest car will be the one that reaches the highest maximum velocity going down the ramp.
Velocity will be measured with a computer-interfaced Motion Detector.
OBJECTIVES
In this contest, you will:
* Apply knowledge gained from lab 1 and 2 to a new scenario.
* Have a little fun.
GUIDELINES
1. You may use your own car or temporarily modify a laboratory car supplied by your teacher. You are encouraged to
make changes that will increase the speed of the car.
2. The car may only be powered by the pull of gravity. It may not be otherwise pulled, pushed, or propelled.
3. You are encouraged to experiment and practice before the contest.
4. During the contest, your car will get two runs down a ramp set up by your teacher. A Photogate will be used to
measure velocity as in Lab #1, “Introduction to Velocity.” The greater velocity of your two runs will count, and the
winning car is the one with the highest maximum velocity.
Lab #4: Instantaneous vs. Average Speed
In these lab activities, you'll investigate the relationship between instantaneous speed and average
speed, and see how a series of average speeds can be used to deduce an instantaneous speed.
Background
An average speed can be a useful value. It's the ratio of the overall distance an object travels and the amount of time
that the object travels. If you know you will average 50 miles per hour on a 200-mile trip, it's easy to determine how long
the trip will take. On the other hand, the highway patrol office following you doesn't care about your average speed
over 200 miles. The patrol officer wants to know how fast you're driving at the instant the radar strikes your car, so he or
she can determine whether or not to give you a ticket. The officer wants to know your instantaneous speed.
If you measure average speed of a moving object over smaller and smaller intervals of distance, the value of the average
speed approaches the value of the object's instantaneous speed.
In this activity, you will use two photogates to measure the amount of time it takes for an object to move a measured
distance. You will enter the measured distance into the computer (since the computer has no way of knowing the
distance between the two photogates). The Logger Pro program will calculate the average speed based on the distance
you enter, and the time that is measured. Then you will change the distance over which the object's motion is measured
and repeat the process.
Set-up
Photogate set up at the
90 cm mark (this one
DOES move for each test)
4 Books
Wooden board with
hot wheels track
attached. There are
marks at 5 cm
intervals.
Photogate set up at the
10 cm mark (this one
does not move)
Labs 1&3 Adapted from Physical Science with Computers by Vernier
Lab 4 Adapted from Adapted from http://teacher.pas.rochester.edu/PhyInq/Experiments/P03/P03_Average_Speed.html Page 3

Procedure
1. Open the file “4-Average and Instantaneous” from the App$ server in the Science/Logger Pro Files folder.
2. Place the first photogate at the 90 cm mark. Place the second photogate at the 10 cm mark.
3. Confirm that the height of the photogate above the track is correct so that the photogate is unblocked (light off) as it
is positioned above the track, but will give one “block/unblock” event when a car travels through.
4. Determine the overall distance "D" between the centers of the two photogates. Record the value of D in the in Logger
Pro and on this paper. In Logger Pro, you will only enter distances in the first row.
6. Place the Hot Wheels car at the 95 cm mark. Click and release the car. Once the car has passed through
both photogates, collection will stop. Record the velocity in your data table. Press CTRL+L to store the latest run on your
graph. If there was something wrong, do not store the run. Repeat this step two more times.
7. Move the top photogate to the 80 cm mark.
8. Repeat steps 3-6.
9. Continue to move the top photogate closer to the bottom photogate by 10 cm for each test. Stop when the
photogates are 10 centimeters apart.
10. Print your graph.
PRE-LAB QUESTIONS
Manipulated variable: ___________________________ Responding variable: ______________________
Controlled variables (2): ___________________________________________________________________
Hypothesis: If__________________________________________________________________________________, then
__________________________________________________________________________________________, because
__________________________________________________________________________________________________.
Data
Distance between
Photogates (m)
Average Speed (m/s) Calculated Averages for Each
photogate distance (m/s)
Trial #1 Trial #2 Trial #3
Labs 1&3 Adapted from Physical Science with Computers by Vernier
Lab 4 Adapted from Adapted from http://teacher.pas.rochester.edu/PhyInq/Experiments/P03/P03_Average_Speed.html Page 4

QUESTIONS (on a separate piece of paper, please!)
1. At which photogate distance do you think you came the closest to measuring the instantaneous speed of the car
at the 15 cm mark? What was the velocity at this point?
2. Extrapolate your graph back to the y-axis. At what value does the line or curve cross the y-axis ?
3. What experimental situation would the "Y-intercept" represent? Draw a picture.
4. What type of speed would the “Y-intercept” represent…instantaneous or average?
5. What variables can change the instantaneous speed of an object?
6. Are there ways to measure instantaneous speed directly, or is instantaneous speed always a value that must be
derived from average speed measurements? Explain.
7. Which of the average speeds that you measured comes closest to the average speed of the cart as it moved over
the whole track?
8. Look back at Lab #1 when we measured the velocity of a car with one photogate. Did that lab come closer to
measuring average speed or instantaneous speed?
9. Attach your graph to this lab. Be sure to plot and label where the y-intercept would be. Label the point you
think best reflects the average speed over the whole track and label the point you think best reflects the
instantaneous speed at point X1.
OBJECTIVES
In this contest, you will
Lab #5: Make a Track
• Apply knowledge gained from lab 4 to the design of a track with specific guidelines.
• Use a computer to measure speed (both instantaneous and average).
Your teacher will provide you with a track. You must shape the track in such a way that the highest instantaneous speed
is not at the end of the track. Your track may not be a simple ramp. You must draw a picture of this track neatly on a
piece of computer paper, labeling the following:
� Placement of a single photogate to determine the instantaneous speed at the point on the track with the
highest instantaneous speed. Show the location by labeling the distance from the start and end of the track to
the photogate.
� The instantaneous speed at this point.
� The average speed over the whole track.
� Your placement of two photogates to determine average speed. Show the locations by labeling distances from
the start and end of the track to each photogate.
Your grade on this lab is determined mostly by your drawing. Please take your time on this drawing and make it neat.
Be sure to include all required parts. Use colored pencils to differentiate between photogates for average speed and
instantaneous speed. Use the “5-Make a Track” file on the App$ server in the Science/Logger Pro folder.
Is your packet ready to be turned in?? Turn your lab report in separately (do not attach), but do make sure all of the
packet is filled in (10 pts.), and make sure the following are attached:
� Questions for labs 1 & 4 (5 pts. each)
� Graphs for labs 1 & 4 (with proper labels) (5 pts. each)
� Drawing for lab 5 (15 pts.)
You do not need to attach your lab report to this packet. Turn it in separately, please!
Labs 1&3 Adapted from Physical Science with Computers by Vernier
Lab 4 Adapted from Adapted from http://teacher.pas.rochester.edu/PhyInq/Experiments/P03/P03_Average_Speed.html Page 5