Video clips in physics education

Film recordings – video clips – have been used in the teaching and learning processes for decades. At the very beginning, the dominant role was played by television and professionally prepared recordings on portable media (e.g. LaserDiscs). With the advancement of technology and the emergence of new media, as well as the revolution in access to image and sound recording and processing devices, video clips – including amateur ones – have become the dominant path of contemporary visual communication. The paper is of an overview character and discusses examples of educational use of video in physics education in the past and at present, including TV lectures, popular science programs, dedicated video materials and educational environments, software for video measurement and evaluation of learning outcomes. Various illustrations along with literature references are given to outline potential educational pathways in making use of video clips as didactically valuable medium in teaching - learning physics.


Introduction
The brothers Auguste and Louis Lumière, who on February 13, 1895, patented a device called Cinematograph, and on December 28 of the same year organized the first public film screening, are considered to be the first authors of the film recording.Their first movie titled "Workers Leaving the Lumiere Factory", due to its documentary nature, can be considered as the first film of educational value.It is also worth mentioning here that among the works of key importance for the development of cinema was a scientific fantasy by Georges Méliès (1902) entitled "A Trip to the Moon", which used the first cinematic tricks in the history of cinema [1].Moreover the construction of the cinematograph was inspired by the great Polish inventor Kazimierz Prószyński who patented his first film camera, called Pleograph, before the Lumière brothers, and later went on to improve the cinema projector for the Gaumont company.He was also the inventor of the widely used first hand-held camera -Aeroscope.The Lumière brothers considered Prószyński's work to be pioneering in the field of cinema and cinematography.
The twentieth century was a time of rapid development of both image capture and processing technologies and the educational use of video.For almost a century, a huge number of documentary, instructional, popularizing and propaganda films have been produced, with the recipient's role being initially limited to the passive addressee of the content (sound and image).
With time, the video became a tool in the hands of educators and its use began to be an important element of the teachers' workshop -initially mainly teachers of humanities, and soon also natural scientists [2].The media revolution at the turn of the nineteenth and twentieth centuries, the sign of which was the universal availability of image recording and reproducing devices, as well as platforms for their processing and sharing, made video the leading medium for transmitting information [3].From the screens of cinemas and televisions, "a picture worth more than a thousand words" found its way to mobile devices that are almost constantly in the hands of millions of people.Nowadays video clips provide an important opportunity to shape the basic communication abilities and to form students' learning skills.They are also considered as medium to enhance school curricula in ways that can enrich formation of key competencies [4].

Theoretical framework for the educational use of video
The history of the use of educational video clips depends on the nature of the scientific discipline whose teaching -learning processes were supported.With the development of information and communication technology (ICT), it has become crucial to visualize its role in educational activities.Among the time different ways of video uses have been introduced and researched as the tool bringing educational added value to teaching and learning processes.The following presentation and elaboration of examples of physics videos were made in the context of Ruben Puentedura's SAMR model [5].The SAMR model is widely used in research publications to describe and categorize the integration of digital technologies in educational practices [6].It seems to be also able to categorize educational practices, especially those making use of digital technologies.Specifically, that classification is based on the actions and roles of teachers and students using video in variety of educational settings.One must be aware that research findings [7] indicate that categorizing changes in practice using SAMR is relative to teachers' established practice within a specific educational context and may be influenced by teachers' familiarity with the respective technology.As video is a piece of technology such an approach is beneficial.
The model (Figure 1) defines four levels of technology integration in education processes.Their characteristics make it possible to become aware of how ICT tools can be used to increase the effectiveness of educational actions, they also provide information on the level of student involvement.SAMR stands for the first letters of four words in English: Substitution, Augmentation, Modification and Redefinition, characterizing the successive levels of technology use in the teacher's work [8].These levels can be briefly characterized as: • Substitution -this is the basic level of use of technology, in which it is applied to perform tasks that were previously performed effectively also without ICT; • Augmentation -at this level, technology improves the performance of tasks and allows for effective solving of basic problems; • Modification -this is the level at which technology enables the performance of new, previously unavailable tasks and makes the teaching context visibly wider; • Redefinition -at this level, technology enables the implementation of complex activities consisting of tasks and problems that could not have been predicted before.At this highest level, ICT creates educational opportunities that are yet to be discovered.
When discussing, in this theoretical reflection, the examples of video clips use in education that are reviewed below, the author attempts to assign each of them to the appropriate level of the SAMR model.The linking was primarily made based on the time lasting author's experience in using video clips in different educational contexts supported by the literature search.The important argument supporting the choice of such a framework rises also from the study examined how teacher educators are appropriating technological, pedagogical, and content knowledge (TPACK) and substitution, augmentation, modification, redefinition (SAMR) frameworks in their pre-service teacher preparation programmes [9].

Examples of educational use of videos
The selection of examples of the educational use of video clips was prepared on the basis of author's years of experience as a physics teacher of various educational levels, academic lecturer and researcher, as well as on the basis of finding described in number of scientific studies devoted to the subject.

Television lectures
Television lectures, both as live shows and as ,specially recorded readings appeared simultaneously with the development of television.The first educational broadcasts date back to the beginnings of television in almost every country [10].
Many interesting historical recordings, such as famous speeches (e.g.Feynman's Lectures on Physics -The Law of Gravitation Cornell University, USA, 1964) or Nobel lectures (e.g.Isamu Akasaki's, Nobel Prize in Physics, Lecture 2014), can be found on the Internet resources in an open access.These are examples of transferring traditional activities into the space of video transmission, and although it is the use of technology at the level of Substitution, thanks to this procedure, educational content reached a wide audience.

Popular science programs
Due to their nature, popular science programs are a separate form of using video clips for educational purposes that enriches the teaching and learning processes [11].An educational program in the form of a series entitled "Horizon" was broadcast on British television (BBC) since the early 1960s.These productions were usually prepared with the aim of providing recipients with specific knowledge while maintaining the characteristic context, form of narration, and thematic scope.Programs called "Discovery" and "Mythbusters" are among the most recognisable popular science programs produced in the English that are widely used in the context of physics lessons [12].
Game show programs (e.g."Wheel of Fortune" or "Millionaire"), despite the non-educational primary purpose, carried a considerable dose of educational content and therefore could be treated as actions supporting acquisition of certain knowledge.In both cases, the level of technology integration in the education process should be defined as Augmentation.

Video encyclopedia of physical demonstrations
The Video Encyclopedia of Physics Demonstrations™ (VEPD), released in 1992 in the form of 25 video disks, the playback of which required a dedicated device, is a series of professional video recordings showing demonstrations of physical phenomena [13].The number of recordings contained in the 68 chapters of VEPD is impressive and covers the subject scope of the full academic physics course.This material is widely known among workers of academic centers responsible for basic education of physicists (and wider the natural sciences) and is still often used to illustrate both course and popular science activities.Especially demonstrations that required specific equipment or needs unique arrangements are played back with use of video clips.In this case the level of technology integration in the education processes should be considered as Substitution.
The contemporary version of this type of educational materials are dedicated video channels, containing generally open and freely accessible on YouTube platform recordings of various physical experiments -a screenshot of one of them is presented in Figure 2.

Video as crucial element of MOOCs
Massive Open Online Courses for which Khan Academy is the most recognizable example [14] are additional cases of video integration in to education.Short instructional videos along with interactive quizzes and tools for teachers to chart student progress, is a realization of the mission of a free worldclass education for anyone anywhere.The advantage of just-in-time playing along with possibility to introduce new representation of rather classic (physics) content allow claiming that here, the level of technology integration in the teaching-learning process should be regarded as Modification.

Interactive Video Vignette
Interactive Video Vignette (IVV) is an example of integrating video and educational platform into a compact learning environment [15] in many aspects similar to MOOCs but going a step further in implementation by giving the educators opportunities to structure the materials in dedicated especially design environment.IVV brings a range of interactivity to a traditional online presentation -users not only play stored content (including videos) in a specific order, but the sequence in which they are presented depends on the responses given during the interaction.The effectiveness of IVV in the teaching-learning process is the subject of ongoing didactic research [16].
A collection of sample vignettes is generally available, along with the Vignette Studio software, which allows you to create your own materials of this educational layout [17].The tool allows students to create tasks to be performed remotely by themselves and provides an environment for individual and group learning.Moreover, IVV can be used as an introduction to the classes in the reverse physics lesson strategy [18].In this case, the level of technology integration in the teaching-learning process should be regarded as Modification.Figure 3 shows the view of the user interface for the project entitled "Projectile motion".

Video measurements
The first attempts to make video measurements date back to the times of analogue film with traditional film frames.Comparison of images of elements of known sizes (e.g. the distribution of elements of a fence against the background of a moving object) on individual frames of a film shot at a known speed, made it possible to determine the motion parameters of objects whose displacement was recorded [19].
In the era of analogue films, it was an extremely labour-intensive process and was based on the analysis of a series of photos.The digitisation of video and the advent of multiple film recording formats has provided the opportunity to automate the measurement process on video films.Over time, the freely available and non-commercial Tracker software [20] made video measurement a basic tool for motion analysis.For educational applications, there are also other video measurement programs available, among others: CMA Coach environment, PHYWE measure dynamics, NewtonDV.Video measurements are the subject of a number of educational studies, resulting in proposals of educational materials for students and teachers [21].The idea behind video measurement is simple: a selected element, whose movement we want to analyse, is tracked (manually or automatically) on individual frames of the video and then indicated by a marker (cursor).Appropriate scaling of the image and information on the number of frames recorded every second, allows one to track the location of a selected detail visible on the film (an object or its characteristic point) in time.It is enough to place an element of known size on the screen during motion recording and enter the information about its dimension into the program.In this way, information about the actual displacement of the indicated (tracked) object is obtained.On the other hand, the information about the time of movement is gained from the information about the frame rate of the film [22].
Both physical phenomena from our surroundings [23] and animated reality can be subjected to such a measurement procedure.It could be used for example in order to determine whether the physical laws apply in our students' favorite cartoons.In both cases, the level of technology integration in the education process should be defined as the highest -Redefinition.Figure 4 shows the measurement frame and selected results of the motion analysis of one of the heroes of the series entitled "Penguins from Madagascar".

Video clips in the process of evaluating learning outcomes
Video clips are used to record educational processes that are going on during lessons, educational activities, laboratories, interviews, and their analysis allows the study of these processes from number of perspectives.Various behaviours and reactions can then be interpreted and described, therefore video clips use is becoming prevalent in teacher education.It is recognized as a fundamental tool to help improving teaching and learning and for assessing effective education [24].
The use of video as a component of assessment became popular especially during remote classes.Various platforms such as Quizziz or Kahoot contributed significantly to this, where the video clip can be introduced as an integral part of the question [25].Due to the complexity of the steps to be taken to prepare video formative assessments, this kind of integration of technology in the teaching-learning process should be defined as Redefinition.
Such educational platforms can also be successfully used as part of a project method called WebQuest or constitute the culmination of student work.This project method primarily uses students' interests in computer and digital resources.From the teacher's perspective, this is an extremely labourintensive approach, but it clearly shows that the virtual network can be a work tool, and even an instrument for verifying knowledge and skills.Video channels can be a particularly valuable source of videos to be used in the evaluation, as well as of their fragments, if we use the appropriate tools to process them (including shortening).A videoblog or channel located on a video platform (eg.YouTube, TikTok) is a form of communication, the main content of which are video clips files, published by the author in chronological order.The files are made available for playback by people visiting the blog or channel.Typically, the formula for this type of video is specific to the author (blogger) and combines many conventions.

Video channels
"Veritasium" is one of the best-known materials on popular science, largely related to physics.These sample network locations (Figure 5 shows a screenshot of the channel) are places where the popularizing formula is combined with an introduction or review narration, and where educational content is an important, but not intrusive, aspect of the message.Hence, this form should be attributed to Augmentation -enhancement level of technology integration in the education process.However, when an educational task consists of preparation of a film by students on a specific physical topic or even setting and running a thematic video blog, we are dealing with the next level of integration -Modification.The video clips from the video platforms are a great triggering element to create education activities in the formula of flipped classroom [26].

Perspectives
Video image is an element that determines the pace of the globalisation process and is directly related to the development of information and communication technologies, which naturally forces educational processes using video to become global as well.Universal access to knowledge creates the need to educate students, above all, to gain the ability to search and process visual information, including the assessment of the reliability of video resources.The key in this process is the awareness of the possibility of modifying the image, and thus influencing its content.
A video in teaching and learning physics is undoubtedly an important element of the teacher's workshop, allowing for the integration of technology into educational processes at a very different level.It becomes especially valuable when we use it in the study of phenomena from the world around us, and thus we show physics as a discipline of human knowledge, as crucial for the development of our culture and civilization.

Summary
In modern science education there is a variety of uses of video, from the carrier of direct information, through the source of data about the phenomena occurring around us, to the element of the learning outcomes evaluation process.The universality of video recording and processing tools favours the multiplication of educational contexts, but at the same time poses the risk of the spread of pseudoscientific content [27].
The time of the COVID-19 pandemic and the long period of conducting classes in a remote format contributed to the dissemination of, among others, the educational potential of video material.During this period, the knowledge and skills of educators, including information and education technologies (ICT) in teaching -learning physics, also increased significantly.However, determining the effectiveness of work with the use of ICT tools and their impact on learning outcomes requires advanced educational research.The effort that is not focused on videos themselves but on the teaching and learning processes that involve video clips in diverse ways.

Figure 2 .
Figure 2. Screen excerpt from the Caltech's Feynman Lecture Hall video channel.

Figure 3 .
Figure 3.View of the Interactive Video Vignette user interface.

Figure 4 .
Figure 4. View of the Coach 6 screen while analysing selected motion characteristics of an animated penguin.

Figure 5 .
Figure 5. YouTube video channel home page view of Veritasium.