Video Analysis in Logger Pro

Inserting the Video

1. “Insert” “Movie”
2. Find the movie file to analyze, then click “Open”

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Adjust window sizes…

...so you can see all 3

Video Analysis Settings

1. Double-click on the movie to open the “Movie Options” pop-up window
2. Check the “Override frame rate…” option, and change it to 240 fps (for iPhone 6 slomo).
3. Check the “First VA point defines movie time zero” option.
4. Type “10” in the box for “Advance the movie ___ frame(s) after adding a new point” option.

Setting up the initial time for the ball drop, t = 0

Move the scroll bar at the bottom of the screen forward until the point in the video where the ball is dropped (for this video it’s frame #413 - check with your teacher…)

frame #

scroll bar

Taking video height measurements for the ball, h

1. Click on the “Add Point” button to the right of the video
2. Carefully click on the center of the ball. A blue dot will appear to mark its position, and it will automatically frame forward 10 frames.
3. Repeat this process until the ball is below the meter stick. (DON’T click below the meter stick.)

At this point your screen should look like this (w/o red stuff)...

Checkpoint: the final time should be between 0.45 and 0.55 seconds (if the ball dropped about 1 m) - if this is wrong, go to the troubleshooting slide(s)

Set the zero height level

1. Click on “Set origin”
2. Click on the bottom of the meter stick to set this as the zero height level

“Set origin”

Calibrate the distance measurement

1. Click on the “Set scale” button
2. Click and drag from the top of the meter stick to the bottom
3. A pop up menu will appear to set this distance - leave it at 1 m and click “OK”

“Set scale”

Now your screen should look like this - w/o red stuff (check the #s)

The starting “y” value should be close to 1.0 m.

Clean up the data table

1. Delete the “X” column by right-clicking and choosing “Delete column”
2. Double-click on the “Y” column and change the name to “Height” with short name “h”
3. Double-click on the “Vy” column and change the short name to “v”

Before...

...After

Calculate Gravitational Potential Energy, E_g

1. Click on “Data” and choose “New Calculated Column…”
2. Set name to “Gravitational Potential Energy,” short name to “Eg,” units to “J”
3. Under “Expression,” type in the mass of the ball * 9.8 (for gravity) * (click on “Variables (Columns)” and choose the height)

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Your data table should now look like this (w/o red stuff)...

• Write down the first Eg value (at time = 0) - this is the TOTAL amount of energy we gave the ball, and it’s ALL potential (stored) energy at the start.
• Any of this energy that is lost has become kinetic energy.

Total Energy of Ball

Calculate Kinetic Energy, E_k

1. Click on “Data” and choose “New Calculated Column…”
2. Set name to “Kinetic Energy,” short name to “Ek,” units to “J”
3. Under “Expression,” type in the total energy of the ball (# from the last step) - (click “Variables (Columns)” and choose “Gravitational Potential Energy”)

Your screen should now look like this...

Graph E_k vs. v

Click on the y-axis label and choose “Kinetic Energy”

Click on the x-axis label and choose “Velocity”

Adjust axes

1. Set your x-axis from 0 to -4 (a pop up stating “The axis direction will be reversed” shows up - click “Yes”)
2. Set your y-axis from 0 to 0.6 or so (make sure all your data is on the graph)

Analyze Ek vs. v graph

1. Click on “Curve fit” and select the best option between linear, quadratic and inverse. (It should be quadratic!).
2. Set “B”=0 and “C”=0
3. Adjust “A” until the curve is the best fit, then click “OK.”

Final result - your graph should look something like...

Troubleshooting tips

• My time at the bottom of the ball’s path is way off…
• Check the frame rate of your video by looking up the device it was filmed on
• Some common frame rates: 30, 60, 120 or 240
• iPhone 4/4s and 5/5s = 30 fps
• iPhone 6/6+ = 30 or 60 fps for regular mode; 120 or 240 fps for slomo
• Samsung Galaxy S4/S5 = 30 fps
• Samsung Galaxy Note3 = 30, 60 or 120 fps
• If you’re not sure, add the data points and check the last time - it should be between 0.45 and 0.55 seconds for a 1.0 m fall

Troubleshooting tips

• LoggerPro doesn’t give me the option to “Insert” the “Movie” (that option is greyed-out)...

Troubleshooting tips

• My video will load into LoggerPro, and I can hear the video when played, but the screen is black...