Tips to support data collection for yesterday’s lab.
Photogates
The Vernier Photogates use a beam of light to detect objects between the two ‘arms.’ LoggerPro identifies the gate state as “Open” or “Closed.”
- Open implies that nothing is blocking the light beam
- Closed implies there is something blocking the light beam.
In most cases, we want to know the time that the gate is closed.
Determining the speed of an object that passes through the photogate
Attach a photogate to a ringstand, then adjust it so a flag mounted on your cart will break the beam of light.
Measure the length of the object that will pass through photogate. When the object passes through the photogate, it measures how long the beam is blocked. The object’s speed (at the position of the photogate) is determined by dividing the length of the object by the blocked time.
This video should walk you through setting up Logger Pro for ‘gate timing.’ The interface she uses different than our LabQuest Mini, but the sensor set up should be the same.
Remember that you will need to attach both photogates, so you can get the velocity of each cart.
More detailed information on the photogates can be found on Vernier’s website.
Here’s a video with more deep background on how the Photogate works.