Video Physics from Vernier is a very handy app for the Secondary physics classroom. Running on all iOS devices it allows the students to analyse the motion of moving objects in videos.
Using the app, students can capture video of an object in motion, then track it automatically by tapping on the object in the video, frame by frame. Video Physics can instantly create trajectory, position, and velocity graphs for the object. The processed video can be saved to the camera roll.
With the app students can capture a new video using the built-in camera or choose a video from your Photo Library. There are some handy sample videos included with the app so that you can practise how to work the software.
The software will track an object automatically or the students can manually add points to the video frame. The app will use an object of known size within the video to set the scale. It’s a good idea to include something like a metre stick in shot. Highlight this object in the app, and set the size, then the distances involved can be calculated automatically. It’s very clever!
Once the data is collected, the app will produce graphs of trajectory, x/y position and velocity.
Tips on using the Video Physics App:
- Try to use a blank wall or sheet of paper as a background. Objects that are very different than their background (black/white) work best for automated tracking. It is also helpful to use a background with uniform color and shading. If the background is too busy, there may be issues.
- Do not move the camera when filming. Analysis assumes the camera is fixed in position. Use a tripod or some other way to fix the camera in place.
- The object in motion should remain approximately in a plane perpendicular to the viewing direction.
- Place an object with known dimensions, such as a metre stick in shot, the same plane as the motion. Use this to scale the video.
It’s a handy app, and if you teach High School Physics, then it’s highly recommended.