Video analysis

Purpose: As an alternative to traditional methods of investigating motion in the classroom, such as ticker tape timers or light gates, it is simpler and cheaper to analyse video clips of the movement of objects. Cameras in mobile phones and tablets can record a brief video which when imported into a video analysis app will track the motion of the subject and calculate its velocity and acceleration.

Teaching approach: When designing investigations into forces and motion use video clips in place of traditional methods of measuring distance and time. This method requires students to tag the object being studied in individual frames in the video, but saves the time involved in calculating and drawing graphs. This method has been used in primary classrooms to show the relationship between speed, distance and time. It can be used to analyse projectile trajectories and spring oscillations as well as linear movement. It has also been used to compare parachute designs and crumple zones.

Preparation: Video collection needs to be from a fixed position at right angles to the direction of movement. Tablet apps such as Video Physics or laptop software such as Tracker are then used to analyse movement in the video clip and will generate a range of graphs to represent different aspects of motion.

The principles of video analysis are explained in this information provided by the manufacturer of the Video Physics app.

• http://livephoto.rit.edu https://www.educationalappstore.com/app/vernier-video-physics

• Website supporting Tracker laptop open source software:

• https://physlets.org/tracker/