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Mastering Video Analysis in Physics: A Comprehensive Guide

Updated: Apr 25

Teachers constantly seek out fresh and innovative strategies to explain complex topics, particularly within the challenging subject of physics. The use of video analysis for learning kinematics stands out as a prime example of cutting-edge technology that meets this need effectively. This article delves into the significant contributions of this technology and unveils the tools educators can employ in the classroom to fully leverage the potential of Video Analysis, also called ViMAS (Video Movement Analysis Using Smartphones).


Contents :


1. A bit of history


Video analysis, or the detailed examination of movement through video sequences, involves capturing the positions of an object or person as they move over time. Its growth as a teaching tool has capitalized on the development of technology, and especially imaging technology.


The first attempts to study motion through imaging date back the 19th century, using a technology called chronophotography. It was pioneered by the French photographer Étienne-Jules Marey, with his photographic rifle capable of snapping rapid sequential images, revolutionized the study of motion in animals, humans, and mechanical objects. In England, Eadweard Muybridge leveraged this technique to prove that horses lift all four hooves off the ground during a gallop, resolving a longstanding scientific debate through photography. In the mid-20th century, the American woman, Berenice Abbott utilized high-speed and strobe photography in her "Documenting Science" project to demystify scientific principles, making complex concepts accessible to a broader audience. Her work remains invaluable for analyzing the dynamics of falling objects and other movements. It continues to be used as teaching material in many classrooms.


The years 1980s saw a new phase in the use of technology to study motion for education with the advent of affordable VHS technology, enabling the filming and frame-by-frame analysis of object movements. Students could pause, fast forward, and mark positions on videos to compute velocities and accelerations, despite the excitement and engagement this new approach fostered, the technology of the time fell short in precision, resulting in blurry videos inadequate for a thorough analysis. Despite the historical achievements of methods like chronophotography, the video technology of the 1990s wasn't up to par with the pedagogical ambitions of this innovative educational strategy.


Today, the advent of modern mobile technology equips every student with the means to not only capture high-quality videos of movements but also to dissect these recordings with advanced, computerized analysis tools on tablets or smartphones, marking a new era in the teaching of mechanics.



2. Educational interest of kinematic analysis by video


Le principal intérêt pédagogique de l'analyse cinématique par vidéo réside dans la capacité de l'élève à mener de bout en bout une analyse de qualité avec les outils qu'il ou elle a dans sa poche, à l'image de ce que pourrait faire un chercheur. Chaque étape de l'étude, que ce soit le choix du sujet, la production de la vidéo, le pointage ou l'analyse des données, présente une opportunité pédagogique unique et donnera lieu à des échanges passionnants avec les élèves.


Carrying out a video analysis of a motion involves four different steps:

  • Selection of the situation to study

  • Creating the video to analyze

  • Pointing and data acquisition

  • Data analysis


In the selection phase, students delve into choosing the focus of their analysis. Whether they're captivated by a specific aspect of a sport, the motion of an object, or aiming to illuminate physical concepts such as uniform or accelerated movements, rectilinear or circular paths, or exploring the dynamics and energy of movement, this decision-making process sparks curiosity and critical thinking.


Following their choice, students embark on capturing the motion through video, confronting and solving various practical challenges. Addressing issues like parallax error, selecting the appropriate frame rate, determining scales, and optimal camera placement cultivates problem-solving skills and technical understanding, culminating in a video apt for detailed analysis.


In the third phase, students pinpoint positions using specialized software on computers, tablets, or smartphones, a task made more accessible with applications like FizziQ. This step introduces them to precise data collection, enhancing their attention to detail.

Analyzing the trajectory data marks the next step. Whether using the same app for marking points, specialized data analysis software, or even a spreadsheet, students dive into the heart of kinematics, turning abstract concepts into tangible realities.


Video analysis is transforming physics education by making it immersive and dynamic. Through real-world videos, students visually grasp and investigate motion, bridging theory with practical application. Advanced software tools enable interactive exploration of kinematic parameters, enriching the learning experience on both individual and collaborative levels. This hands-on approach not only stimulates lively discussions and group projects but also allows for the immediate empirical testing of theories, significantly deepening students' understanding of physics fundamentals.


3. Choosing Your Physics Playground


Physics is not just about studying black holes and quantum mechanics. While these subjects are always inspiring because they allow us to better understand the complexity of our world, to connect the infinitely large to the infinitely small, and to measure the progress made by science, physics is also about understanding everyday phenomena that also hold secrets that we discover with amazement. As Richard Feynman explains, "The beauty of a theory resizes in its simplicity and generality. If a theory is simple and general, it is beautiful, even if it describes only ordinary phenomena.". Studying mechanics through video analysis on smartphones allows students to study these ordinary phenomena, situations they encounter in everyday life, and which are full of mystery and wonder.


What phenomena can students study? It all depends on whether you choose a thematic approach or a conceptual approach.


As part of a thematic approach, one of the most interesting themes to study is the physics of sport. The human body is a fantastic playground and sport is the epitome of its development. The mixture of the study of physics and sport appeals to most students because each has a favorite sport or activity. Each sport contains fascinating subjects of study, as shown by the inventory of winning activities during the Société Française de Physique competition which focused on “Physics and Sports”. More than 100 classes used their wild imagination to study the physics of sports using the free FizziQ app, and studied more than 30 different types of sports like kayaking, handball, shot put, sailing , gymnastics, horse riding, rugby passes, moving players in a football game, paralytic javelin throwing, etc.


You will find in our article 15 inspiring activities that can be carried out in class.


Kinematic study by video also allows the teacher to illustrate physical concepts by studying videos specifically illustrating a movement. Here, for example, are examples of videos that could be used and the concepts attached to them:

  • Uniform movement: Bicycle, person walking, ball thrown on the ground. Study of the trajectory, calculation of speed.

  • Free fall : Falling object. Trajectory, speed, acceleration, calculation of g, calculation of speed vectors, friction.

  • Simple pendulum : Analysis of the oscillatory movement of a simple pendulum. Conservation of mechanical energy, period and length of wire, amplitude, speed at the low point, calculation of speed vectors.

  • Parabolic movement : Object thrown into the air. Study of parabolic trajectory, range, maximum height, flight duration, conservation of mechanical energy.

  • Uniform circular motion : An object in uniform circular motion, such as a ball attached to a rotating wire. Tangential speed.

  • Movement of a spring : Analysis of the movement of an object attached to a spring in vertical or horizontal oscillation. Measurement of the period, amplitude and spring stiffness constant.

  • Friction : Study the effect of the friction of a badminton shuttlecock or an object sliding on a surface or the fall of a drop in a liquid. Distance traveled, speed vector, coefficient of friction.

  • Collision : Study of elastic and non-elastic collision. Kinetic energy of the two objects, determination of the type of collision.

  • Waves : Observe the propagation of waves on the surface of water or on a tight rope. Analyze the propagation speed, wavelength and frequency of the waves.

  • Complex movements: athlete movements involving several sequences such as pole vaulting. Energy, speed, acceleration

  • Center of inertia : Study of an object launched into rotation. determination of the center of inertia


Free analysis or illustration of concepts, we see that kinematic analysis by video presents immense opportunities to allow students to discover and better understand the physics of movement.



4. Mastering Video Creation for Motion Analysis


Contrary to what one might believe, making the video is the most difficult part and probably the most rewarding for the students. During this realization they will discover all the elements which will later be important during the analysis.


We have described in another article 7 tips for making a good video for motion analysis and which can be summarized as follows.


The use of a smartphone, capable of filming in 720p resolution, is sufficient to create usable videos, making this technology accessible to all students. To ensure the accuracy of the analysis, it is crucial to stabilize the camera, ideally by using a tripod or placing the device on a stable surface, thus avoiding any spurious movement that could distort the interpretation of the movement of the object. filmed.


Adding a scale to the video field is necessary to match the dimensions on screen to those in the real world. This allows precise analysis of the movements and dimensions of moving objects. It is also important to maintain a constant distance between the moving object and the camera to avoid distortions due to variations in distance, which can be managed by positioning yourself properly or using the zoom judiciously.


Making pointing easier is another crucial aspect to get good data; the filmed object must be clearly identifiable and contrasted with the background to allow precise marking of its successive positions. This may require moving closer to the object or using a distinctive sign to facilitate tracking. Adjusting the frame rate based on the speed of movement is also essential for capturing sharp, usable images, with particular attention to respecting the time gap between images during analysis.


Finally, checking the framing before you start recording ensures that the entire desired movement sequence is included in the video, allowing for detailed analysis from start to finish. These practices optimize the use of kinematic videos for the study of physics, making learning more interactive, accurate, and engaging for students.



5. Best Software for Video Analysis


Once we have produced the video, we must analyze it to make measurements of the physical phenomena that we wish to study. For this we use pointing software. This software will have several functions:

  • Scaling which allows you to match the screen scale to the size in the real world.

  • Frame-by-frame motion pointing

  • Calculation of positions and its derivatives from pointing and scale

  • Data export


The analysis can be done on computers, smartphones or tablets and require specific softwares. Some are free of charge, while and some others like Vernier require fee based enrollment.


For computers the most used software are:

  1. Tracker : Tracker is free and open-source software that combines video analysis and modeling. It allows users to analyze and compare movements from videos.

  2. Logger Pro : Developed by Vernier, Logger Pro integrates video analysis with a suite of scientific data collection and analysis tools. Although it is paid, Logger Pro is widely used in educational establishments for its intuitive interface and its many features.

  3. PhysMo : PhysMo is an open-source video analysis software specifically designed for educational needs. It allows you to analyze motion in videos recorded using any standard camera.


For tablets, smartphones and Chromebooks, the two best apps are:

  1. FizziQ: A free application available on smartphone and tablet which allows pointing, calculation of positions, speed, acceleration, energy and rotation of mobiles as well as data analysis in an experience notebook and their export in Excel and Python format . Fizziq also has a library of more than 30 videos accessible for free.




  1. Vernier Video Physics : Available on iOS, this paid application allows you to create movement diagrams from videos taken with the smartphone.


Using smartphones and tablets for kinematic analysis is particularly interesting for several reasons: firstly because the videos created by students are most of the time on their smartphones or tablets, then because the analysis is particularly quick to carry out. and does not require the use of equipment that takes a long time to set up or is not always available, finally because it familiarizes students with the numerous possibilities of the digital tools they use.



6. Data analysis


After the pointing and data acquisition stage comes the final data analysis phase. From position data we can calculate all the characteristic elements of the physics of movement: speed, acceleration, rotation, kinetic energy and potential energy. These measurements will make it possible to characterize the phenomena involved and to verify the theory through experimental calculation.


During this process, we will pay particular attention to the modeling or adjustment of data (in English fitting). Indeed, the data from kinematic analysis by video can present variations due to pointing errors and adjustment is an essential step to obtain usable data. In the FizziQ application for example, position data is adjusted for the calculation of speed and acceleration by quadratic adjustment. Additionally, the graphs in the experiment book can also be modeled with a quadratic or linear fit.


In addition to trajectory, speed or acceleration calculations, precise trajectory data makes it possible to study a large number of physical phenomena such as the calculation of g, the analysis of friction, the conservation of mechanical energy, the range of a parabolic flight, tangential acceleration, amplitude and spring stiffness constant, types of collision, center of gravity, ...


Most pointing software allows data export, which makes it possible to study the data with specialized analysis software or for example with Excel. Note that the FizziQ application also allows you to export in Python line format, which significantly simplifies use for students.



7. Conclusion


Video motion analysis is not just a new approach to the study of physics: it is a powerful educational tool that resonates with the learning sensibilities of the digital age. By combining theory and practice and providing an interactive platform for exploration and analysis, it deepens students' understanding and appreciation of the complex dance of forces and movement that governs our universe.



Bibliography


1. Wee, Loo Kang & Lee, Tat. (2012). Video Analysis and Modeling Tool for Physics Education: A workshop for Redesigning Pedagogy.

2. Chernetckiy, Slipukhina, Kurylenko, Mieniailov & Opachko (2021) The Application of Tracker Video Analysis for Distance Learning of Physics

3. M. Ramli, K. Chan, and W. Fen, Study of Simple Pendulum Using Tracker Video Analysis and

High Speed Camera: an Interactive Approach to Analyze Oscillatory Motion. Solid State Science

and Technology

4. Brown, Doug. (2008). Video Analysis and Modeling in Physics Education. L2001

5. Lee, TL, Wee, LK, Cheng, SSS, & Tan, YL (2010). Learning Physics of Sport Science through Video Analysis and Modeling Retrieved 02 June, 2010

6. Finkbiner MJ, Gaina KM, McRandall MC, Wolf MM, Pardo VM, Reid K, Adams B, Galen SS. Video Movement Analysis Using Smartphones (ViMAS): A Pilot Study. J Vis Exp. 2017 Mar 14


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