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Motion analysis using chronophotography

Updated: Apr 16

Do you want to analyze motion using chronophotography in class? This article contains all the information you need to find the right pictures, analyze movements with FizziQ, and share the data in a spreadsheet.


Table of contents:


Why use chronophotography in science?


Let's start with a bit of history! Three photographers developed the technique of chronophotography, a photographic technique that involves capturing multiple images of a moving object at regular time intervals, and assembling them into a single image. These artists and scientists are Étienne-Jules Marey, Eadweard Muybridge, and Berenice Abbott.


Chronophotography was invented by French photographer Étienne-Jules Marey in the 19th century and was widely used to analyze the movements of animals, humans and mechanical objects. He invented the photographic rifle, a device capable of taking several images in rapid succession on a single photographic plate.


Eadweard Muybridge is famous for his studies on animal movement, particularly for his series of photographs titled "Sallie Gardner at a Gallop." It was thanks to him that the controversy over whether horses lift all four legs off the ground during gallop was resolved. His analysis showed that this was the case, and it was the first time that photography was used to solve a scientific problem.


Berenice Abbott was an American photographer known for her documentary photographs of New York City in the 1930s. In the 1950s and 1960s, Abbott worked on a project called "Documenting Science," where she explored various photographic techniques to illustrate scientific principles and make science more accessible to the general public. As part of this project, she used high-speed and stroboscopic photography methods to capture images of fast-moving phenomena.


These photographers showed that chronophotography could be a useful tool for the study and teaching of science. Thanks to their work, teachers have today new tools to introduce mechanics to their students.


Which photos to use in class?


Ideally, students should be involved in producing the images. Unfortunately, producing chronophotographie pictures through Photoshop or other software is a time-consuming process, and the application that existed for creating one's own pictures from a film is no longer available. If you want to involve your class in the production, it is better to turn to the analysis of cinematic videos.

On the internet, you can find beautiful chronophotographie pictures that are perfectly suitable for classroom work. You can also find them in science books. You can also use old photographs that are fun for students. On the page https://www.fizziq.org/chronophotographies, you will also find many pictures to use in the classroom.


With FizziQ you can study almost any type of chronophotography : a drawing, an image, the photo film, or a chronophotography available on a web address or on fizziq.org. All these images can be downloaded in the app and used to study movement.


Remember : if you have a document on which a chronophotography is printed and you wish to analyze this image with FizziQ, the easiest way is to take a photo of this document, and it can be reused directly in the app.


What chronophotography are to be used in class? It must have several characteristics:

  • The scale must be easily readable

  • Duration between images must be known

  • The different positions of the object should be easy to point accurately (no blurring or overlapping)

  • The object must be at all time at (or close to) the same distance from the objective

We published 7 important recommendations when creating a cinematic video and these remarks can also be useful in chronophotography.


What lessons with chronophotography ?


A chronophotograph allows you to obtain the following information about the movement of an object or person: x and y positions, velocity vector, acceleration vector, kinetic and potential energy, angle, and rotation speed.


This information allows you to study virtually all aspects of mechanics programs in middle and high school:

  • Uniform motion: bike, walking person, ball thrown on the ground. Study of trajectory, calculation of velocity.

  • Free fall : Study of free fall in the air. Calculation of g, calculation of velocity vectors, friction.

  • Pendulum : Analysis of the oscillatory motion. Verification of the formula for the period, amplitude, speed at the low point, calculation of the speed vectors.

  • Parabolic movement : Study of the parabolic motion of a projectile launched with a certain speed and angle. Parabolic trajectory, range, maximum height, flight time, conservation of mechanical energy.

  • Uniform circular motion: Object in uniform circular motion, like a ball attached to a spinning thread. Tangential speed.

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

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

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

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

  • Center of Inertia: Study of an object thrown in rotation. Determination of the center of inertia.

  • Complex movements: movements of athletes comprising several sequences such as the pole vault. Energy, speed, acceleration


Uploading a photograph to FizziQ


The kinematics module is accessed in the application from the Tools tab > Kinematics Analysis. Select Chronophotography and access the photo selection menu.


The user can download:

  • an image of the film. Pressing My Images and accesses the library and choose any available image

  • one of the images in the application among those of free fall, parabola or pendulum

  • an image available on the internet, or coming from the library of the site fizziq.org, either from an address where the image file is located

To download an image from our Image and Video Library: press "FizziQ Resources", then copy the link of the image you want to add. Return to the application and press "Internet", then "Paste" icon. The image is ready to be analyzed.


To download an image from a file available on the internet: place a copy of the internet link of this image in the clipboard, in the application, press "Internet" then the "Paste" icon.


Analysis

The analysis of a chronophotography with FizziQ is done in three steps:

At any time, you can return to the previous step to change the scale or modify movement points.


Scaling

Scaling is done in three steps that can be done in any order:

- position of the Origin by moving the ruler with the finger

- position of the End of the ruler

- enter of the ruler length

As long as these three steps have not been completed, you cannot move on to the next step. Once the scaling is done, press the "Pointing" tab on the right


Pointing

Pointing consists of two steps:

- check that the time interval is the one that corresponds to the sequence of images. This interval is entered in milliseconds,

- enter all the movement points by moving the target with your finger to position it, then tap on the screen to validate.

If you made a mistake you can cancel by pressing the trash can. To hide the indications which can disturb the pointing one can press on the eye. Finally the camera allows you to take a screenshot.


Results

After pointing out the entire movement, we can then move on to the analysis which is done in the experiment notebook using the graphic possibilities of the application:

- select the data you want to transfer to the notebook. A maximum of 3 data can be selected,

- transfer the data by pressing Notebook on the right,

- the application switches to the experiment notebook and the data is added at the end of the notebook.


Use the experience book


The experiment notebook is one of the specific features of the FizziQ application. It allows you to organize data, analyze it in the form of a graph, and to add text and photos to document your reasoning. It can be exported in PDF or CSV format.


Data from kinematic analysis is added to the notebook as a new observation card in the form of a table. A table in FizziQ is equivalent to a spreadsheet. Lines can be added by pressing the + button or removed by swiping left. The last line of the table allows you to add statistics.


At the bottom of the card, you will find the graphical possibilities of the table. The buttons allow you to create graphs combining the 3 data columns. In a graph, the + and - buttons allow you to change the scale and the up-down button centers the graph. The button on the right allows you to perform linear or quadratic interpolations of the data.


The table is an evolving tool, and other functionalities are regularly added.


Export data


With FizziQ you can export data very easily in Excel format. Many teachers prefer to use a spreadsheet on a computer rather than using FizziQ's table.


To export a table to a file in CSV format:

  • in the notebook, press the Share icon at the top right of the screen

  • select "Create a CSV file"

  • decide on a decimal separator, either a point or a comma, depending on the configuration of your spreadsheet

  • export the document


To know more


The kinematics module and the use of videos to make kinematics in FizziQ is described in this tutorial prepared our team.


You can also consult the excellent video by Jean-Michel Courty for Billes de Sciences on the use of the FizziQ application for kinematic analysis.


Finally, chronophotographie is one method to study movements. Studying motion through video analysis is also another innovative method to teach about mechanics and movement. To discover how to use Video Analysis in physics, check out our article : Mastering Video Analysis in Physics: A Comprehensive Guide



















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