In last week’s post, we learned about how the GlobiLab software makes data analysis immediate and effortless. Today, you will learn how to use the award winning Labdisc and the GlobiLab software to teach your students about gravity with the Labdisc Free Fall Activity. This experiment will help you educate your students about Sir Isaac Newton’s second law of motion and acceleration, and teach them how to measure gravity.

Setting up the experiment

1. Program your Labdisc

1. Use the scroll key (right button) to program your Labdisc and enter set-up with select key (left button)
2. Set the sensors using the select key

1. For this activity, you will measure distance. To do this, select the ruler icon by pressing on it twice.
2. Please note: You may need to turn off a previously used icon by pressing that icon (i.e. if the microphone is on, press the microphone sensor to turn off)
1. Select the main button to return to the main screen
2. Navigate to sample rate (You may need to advance with the right button to choose 25 samples)
3. Press the main button to return back
4. Select # of samples by pressing the scroll key and select 1,000
5. Confirm with select key
6. Press the main button to return back to main screen (You may need to press a couple of times)
7. One more time, check for distance by selecting the ruler icon
8. Open the back cover (located under the Labdisc). This must be open in order for the sensor to work.

Running the experiment

1. Person A – Hold the Labdisc about chest high (or 1.2 meters above the surface from where you are measuring). Make sure hands are not underneath the Labdisc, as it will interfere with the data collection.
2. Person B – Hold the ball underneath the Labdisc. The Labdisc should read between .2 or .3
3. To avoid errors, hold the ball and Labdisc steady
4. Person A – Press the sample button, pause for a moment, and say “Drop”
5. Person B – Drop the ball. Make sure to not use any force when dropping the ball
6. Person A – Press the stop button once the ball stops bouncing

Viewing data

1. If the software is already open and the Labdisc has been connected via Bluetooth, data should automatically upload.
2. If not already open,
   1. Connect to computer via Bluetooth
   2. Open software (GlobiLab) on your computer (lower right corner, Bluetooth icon should turn from grey to blue)
   3. Use the green button and choose to download data
   4. Download previous to show all samples or last to show just the most recent data collection
   5. Choose the first data set you did and press download (note that the time and date will be incorrect as you did not set up the GPS during this activity)
3. Review the graph and bounces that are represented

1. Everything on the graph is inverted because it is measuring the ball’s distance to the ground (how far the ball moves away from the device)
2. Identify points of error such as a steady hand or throwing the ball down
1. Use the Marker icon (graph with a red X), click on a peak of a large bounce and click on the peak of a second bounce located a bit further down the graph. Next, use the crop function (black square icon) to see a closer view of the ball jumps on the graph.

1. Confirm delete all other data (You can always reload the full data again if needed)
2. Right click on Distance (located on the right side of the screen) to see each individual plot points (there are 25 points per second)
3. Click on two data points to get time differential and distance differential of each point
4. Click on the graph icon with the drop down menu and choose the curved icon that represents a line of best fit
5. Expected value is 4.9. The number represents the acceleration due to gravity (1/2 g)

1. You can use this data for many other measurements depending on grade level (for example: loss of energy)

See how this can be done in your classroom here: https://www.youtube.com/watch?v=QrEyjY-lPdU&feature=youtu.be  

Want to learn more?

Be sure to download our Labdisc eBook: https://34.201.222.12/getting-started-labdisc-ebook/

Visit our Labdisc page: https://34.201.222.12/product-offerings/labdisc/.

Teq offers Professional Development to support your STEM, STEAM, and Labdisc initiatives. To see what courses are currently available, take a look at our Professional Development Catalog, here:  https://34.201.222.12/wp-content/uploads/2016/07/Teq_PD_Catalog_2016_web.pdf