Name: Date: Partners: Purpose: To investigate and analyse basic properties of motion using a Vernier Go! Motion Detector and logging software. Materials: 1. PC with Logger Lite Software installed. 2. Go! Motion detector 3. USB cable 4. Ramp, and materials to support ramp 5. Playground ball Setting up Go! Motion sensor: 1. Plug the USB Cable into the Go! Motion sensor, and plug the other end into the PC. You may have to look at the back of the PC tower to find a USB port. 2. Launch Program Files / Vernier Software / Logger Lite 3. On the Logger Lite toolbar, click Experiment / Data Collection 4. Make sure the Mode option is Time Based 5. Set Length equal to 10 seconds. 6. Click Done to close the Data Collection dialog box Gathering Data with the Motion Sensor: The motion sensor uses ultra-sonic waves to detect motion. Results might work best if the person standing in front of the motion sensor holds a flat object such as a textbook, binder, or piece of cardboard in front of him or her. Also, try to keep any wireless devices away from the motion sensor to avoid any possible interference. 1. With one person operating Logger Lite, and another person in front of the motion sensor, hit Collect while a teammate walks backwards and forwards in front of the Go! Motion sensor. 2. Let your other group members have a turn in front of the motion sensor. If you press Collect a second time, you will just record over the previous data set. You can clear the data at any time by simply clicking Data / Clear All Data. Take a few minutes here to get used to logging data, and clearing data sets. Rev 09-01 1/11
Activity P1 Position vs Time for Different Walking Speeds With your group, make some predictions about what it looks like on a Position / Time graph if you walk steadily slowly towards the detector, vs walking steadily quickly towards the detector. 1. PREDICTIONS a. On the graph below, draw what you think the graph will look like for a person walking slowly, but steadily, away from the detector. Label it Slowly Away b. On the graph below, draw what you think the graph will look like for a person walking quickly, but steadily, away from the detector. Label it Quickly Away c. On the graph below, draw what you think the graph will look like for a person walking slowly, but steadily, towards the detector. Label it Slowly Towards d. On the graph below, draw what you think the graph will look like for a person walking quickly, but steadily, towards the detector. Label it Quickly Towards Position (m) Rev 09-01 2/11
2. DISCUSSION: With your group, discuss the following questions. Jot down your thoughts, as well as any differing opinions in your group. a. What is the main difference between the lines for faster and slower motion on your predicted Position-Time graph? b. What is the main difference between the towards and away lines in your prediction? 3. OBSERVATIONS: a. Have someone in your group walk steadily away from the detector while facing the detector and computer screen. Do this a few times until your group gets a consistent result. Sketch the typical graph that represents this motion below. Label it as slowly away observed. Position (m) Rev 09-01 3/11
b. Repeat this process for the remaining three types of graph: quickly away observed, slowly toward observed, quickly toward observed. You should have 4 sketches in total on the above graph. c. What was the difference between the observed faster and slower motions on the Position-Time graph? d. What was the difference between away and toward on the observed graph? e. Did your group s predictions match the observations? If there were any differences, discuss with your group and list any possible reasons why there were differences. Activity V1 Velocity Curves In the Logger Lite application, click Open, and open C:/Program Files/ Vernier Software/ Logger Lite /Experiments/ Middle School With Computers/ 33c Graphing Motion Take turns with your group to log velocity-time data using the motion sensor, to get used to how these graphs look. Move backwards and forwards at different speeds, try swinging your arms vs. keeping your arms still, etc. Rev 09-01 4/11
1. PREDICTIONS a. On the graph below, draw what you think the velocity-time graph will look like for a person walking slowly, but steadily, away from the detector. Label it Slowly Away. b. On the graph below, draw what you think the velocity-time graph will look like for a person walking quickly, but steadily, away from the detector. Label it Quickly Away c. On the graph below, draw what you think the velocity-time graph will look like for a person walking slowly, but steadily, towards the detector. Label it Slowly Towards d. On the graph below, draw what you think the velocity-time graph will look like for a person walking quickly, but steadily, towards the detector. Label it Quickly Towards Velocity (m/s) 2. DISCUSSION: With your group, discuss the following questions. Jot down your thoughts, as well as any differing opinions in your group. a. What is the main difference between the lines for faster and slower motion on your predicted Velocity-Time graph? b. What is the main difference between the towards and away lines in your prediction? Rev 09-01 5/11
3. OBSERVATIONS: a. Have a member of your group walk slowly away from the detector, at a steady pace. Do this a few times until you get a consistent result. Sketch the typical graph that represents this motion below. Label it as slowly away observed. Velocity (m/s) b. Repeat this process for the remaining three types of graph: quickly away observed, slowly toward observed, quickly toward observed. You should have 4 sketches in total on the above graph. c. What was the difference between the observed faster and slower motions on the Velocity-Time graph? d. What was the difference between away and toward on the observed graph? Rev 09-01 6/11
e. Did your group s predictions match the observations? If there were any differences, discuss with your group and list any possible reasons why there were differences. f. How did the appearance of the graphs differ from the similar exercises you did for the Position activity? Activity A1 Acceleration: Rolling Down a Ramp 1. Minding the USB connector cable, carefully place the Go! Motion sensor on the floor. 2. Make a ramp on the floor in front of the motion sensor. Be careful that any books you use to prop up the motion sensor do not block the sensor. 3. You may need to prop up the motion sensor depending on the height of the ramp. 1. PREDICTIONS a. Consider the following: a ball is rolling down a ramp, and then at the bottom of the ramp the ball continues to roll along a flat, horizontal floor. Can you predict the shape of the position-time graph and velocity-time graph for the ball rolling down the hill? On each graph (on following page), label the part of the line that represents the ball rolling downhill, and the ball rolling horizontally. b. Describe in words how the velocity of the ball changes over time as it goes down the ramp and then onto the floor. c. Describe what you know about the term acceleration. Think, for example, what it means when a car is accelerating what do you notice on the speedometer? Where does the ball accelerate on the ramp, or as it rolls flat on the floor, or both? Rev 09-01 7/11
Position (m) Velocity (m/s) 2. DISCUSSION In your group, discuss the graphs you sketched for the predicted position-time, and velocity-time graphs. Did any members in your group have significantly different ideas of how the graphs might look? Jot down any differing opinions. Rev 09-01 8/11
3. OBSERVATIONS In the Logger Lite application, click Open, and open C:/Program Files/ Vernier Software/ Logger Lite /Experiments/ Middle School With Computers/ 33e Graphing Motion. Note that 3 different types of graphs are shown: Position, Velocity, and Acceleration. Do a few practice runs with the motion sensor. Hold the ball at the top of the ramp, hit Collect, and then let the ball roll down the ramp. When you ve got a satisfactory data run, sketch the results below: Rev 09-01 9/11
a. Is the Position-Time graph consistent with what you predicted? If not, why? Label on the observed graph where the ball was going down the ramp, and where it was rolling flat on the floor. b. Look now at the Velocity-Time graph. When is the velocity increasing? What is the ball doing in this time period? When is the velocity constant (in a horizontal line)? Is this what you expected? c. Now look at the acceleration graph. Can you explain why this graph has lots of bumps or waves? d. Bumps and wiggles aside, when is the acceleration approximately constant? Look at the Position and Velocity graphs, and describe what is happening to the ball at this point. Why is acceleration constant during this time? e. Why does the acceleration go to approximately zero? What is happening to the velocity when the acceleration is zero? f. Revisit your initial definition of acceleration. Now that you ve seen graphs of acceleration, velocity, and position for the same object in the same period of time, can you revise your definition at all? Share your ideas with your group and see if you can come up with a consensus. Rev 09-01 10/11
Summary and Suggestions for the Future: a. What were the main things that you learned from this activity? b. Can you think of alternative hands-on ways in which these concepts could be demonstrated? c. What changes (if any) would you make to teach these activities in a Grade 7-8 classroom Rev 09-01 11/11