Creating Physics Phone Experiments

Creating Physics Phone Experiments

Author: Vera Koester, Sebastian Staacks

Dr. Sebastian Staacks, RWTH Aachen University, Germany, has created the app phyphox that uses the sensors of the smartphone to record data for physical experiments. A website offers ideas for experiments and explanations in video and text form, and in social media, there is an exchange and discussion about experiments.

Here Sebastian Staacks speaks to Dr. Vera Koester for ChemistryViews about his fascination for physics and open source software, the app, its creation, and how and where it is used.



What gave you the idea for this app?

The head of our institute, Professor Christoph Stampfer, was the first of us to learn that you can use the phone’s sensors for physics experiments. After all, we are by no means the first group to do this, but we had some ideas that could not easily be implemented with existing apps. Since I already had some experience in app development, we decided to create our own app.

First, this app was only meant to address our own introductory lecture for physics students, but soon we realized that it had some features that might be interesting to others as well. So we published it in September 2016 without the faintest idea that it would become so huge.



What is particularly important to you about the app project?

Personally, I have always been a big fan of open-source software and open interfaces that allow integrating the software into other projects. Phyphox is open source, and it features a generic interface to exchange data with almost any Bluetooth Low Energy device. You can read data from phyphox through the local network and tell phyphox to collect data from the internet. This may not be the main use for the first-time user, but it provides almost unlimited possibilities to come up with new experiments with all the sensors and data that are available to you—from using phyphox and the smartphone sensors to control musical instruments to combining the data from users around the globe to trace the Sun across the winter solstice to determine the Earth’s axial tilt.



What was the biggest challenge or the biggest surprise during the development?

Phyphox’s success and the sheer amount of feedback that it encompasses was definitely a great surprise and a challenge I did not expect. In the beginning, I was the developer, webmaster, tech support, social media manager, and, of course, the instructor who held teachers’ trainings, created our demonstration videos, and gave talks at conferences. I love every single aspect of this—well, maybe not the tech support—but as phyphox has seen more than a million installations by now, I had to admit that I need some help.



Do you have a favorite experiment?

I find it hard to pinpoint THE favorite experiment.

In terms of simplicity and accessibility, I would say that it is our method to determine the speed of sound with just two phones. It can be understood by everyone and only requires basic arithmetic to get to the result.

In terms of playfulness, I would say that detecting when someone flushes the toilet on a plane with the pressure sensor of your phone offers a nice mix of surprise and absurdity.

But as an overall favorite experiment, I usually come back to measuring centripetal acceleration by placing the phone in a salad spinner. This just has the right mix of craziness and physics while showcasing many strengths of phyphox, including the combination of multiple sensors, data analysis, and remote control from another device as you cannot control your phone while it is spinning.



Have you ever broken your phone during such experiments?

No, luckily, I only scratched one severely while shooting an instruction video. I think that the danger to the phone during the experiment is not that high, because one is very aware of the unusual situation and focussed on the phone. So, I did not damage the phone during the experiment, but afterward, when I tried to pick up too much gear at once and dropped the phone to which I was no longer paying any attention.



What is the difference between your app and similar apps from other providers?

I think the most important difference is our method to keep the app simple while offering an extreme range of customization options that are not even visible to the user at first. A new user might notice how many preset configurations there are in the main menu and how smooth our graphs are, but he or she might even wonder where to find any settings or customizations.

A teacher can show phyphox to students and simply instruct them to pick a preset experiment from the menu and tap start to begin the experiment without worrying about complicated instructions on how to set up sensors, acquisition rates, averaging, data analysis, and the correct visualization.

Phyphox does not offer an overloaded interface with these settings but, instead, anybody can define their own configuration with our web-based configuration editor or by directly editing our file format and even existing experiment configurations. In fact, not a single configuration in phyphox is hardcoded—everything can be changed by the user.

A teacher can pick data sources like the sensors, the microphone, or GPS, apply data analysis from simple arithmetic to Fourier transforms and interpolation, and decide precisely which data is plotted along with labels, instructions, buttons, etc. In the end, the teacher offers the custom configuration to the students in form of a QR code and again, they are ready to go without having to deal with any overblown settings menus.



Today there is a whole team behind Phyphox. What are you doing, and how is this financed?

Until recently, it was a typical research team. Besides me, there was the head of our institute, one or two Ph.D. students, and an ever-changing number of students working on their Bachelor/Master thesis in physics education. They have been of great value as they usually worked on specific experiments and teaching scenarios as part of publicly funded projects.

The general development of phyphox is funded by our institute, and we have received great support from our University, the RWTH Aachen, in this regard. Luckily, since earlier this year, we have two new members in our team who work permanently on this project to bring phyphox to a larger scale. They are funded by the Hans-Hermann Voss foundation, and I think that as the project continues to grow and exceed the scope of our institute, we will have to approach more foundations for funding opportunities.



What are the homelabchallenges?

This was a spontaneous idea at the beginning of the COVID19 lockdown. Phyphox allows students to conduct experiments with their own phones and some simple household materials. So we created a short series of videos that challenge the viewer to do a specific experiment within a few minutes.

In fact, we saw a strong increase in views of our experiment videos as more countries went into lockdown, and teachers probably sent the video links to their students.



What kind of feedback have you received?

Teachers seem to love phyphox. They tend to disagree on many details, like whether students should use their own devices, what is the minimum age for phyphox experiments, and which particular experiments actually help to engage and motivate students, but you will have a hard time to find a teacher who is not at least fascinated by the possibilities they suddenly get from this free tool.

We also get a lot of good feedback from students, who especially like that they could use their constant companion rather than some odd lab equipment. However, the app is, of course, not a cure-all. A student who hates physics will not suddenly love it because of a single app.



Is the app being developed further?

Yes, my to-do list is growing faster than I can implement new ideas. One of the biggest opportunities that we have not even touched so far is the phone’s camera, and it is the next major item on that list.



When did your interest in science begin?

That would be a good question to my parents as they love to mention “sciency” habits from my childhood that I cannot even remember. I always wanted to understand how things work, and I always loved to apply my knowledge to create something.

But as much as I would like to name a big scientist as a role model here, it was probably Sci-fi from the late 80s and early 90s that romanticized science such that I could not help but become a physicist.



Please tell us a bit about how your career has developed?

After I got my Ph.D. in condensed matter physics, I actually planned to become a physics teacher. Part of this decision was motivated by the fact that, unfortunately, the typical science career does not allow to settle in one location and, therefore, was not compatible with my plans to start a family. I found teaching to be an appealing alternative. I was in the process of applying at a local school when phyphox became so successful that I was offered a permanent position at the RWTH Aachen University.



What was your research focused on?

While I started in condensed matter physics researching spin dynamics in semiconductors, my focus has shifted entirely to the didactics of physics. Here it will not surprise anybody if I explain that I focus on the digitalization and the application of modern technology to enhance student experiences.



What do you do in your spare time?

When I am not playing with my son, I love to automate things at home that probably did not need any automation. If I eventually fancy an activity that does not require a keyboard, I play the drums or the guitar.



What else would you like readers of ChemistryViews to know?

In short: install phyphox! Start experimenting with the world around you!



Great advice. Thank you for this interview.

Sebastian Staacks studied physics and finished his Ph.D. on condensed matter physics researching spin dynamics in semiconductors at the RWTH Aachen University, Germany, in 2014. He has first been a research assistant and since 2017, an academic counselor (Akademischer Rat) at the RWTH Aachen University, focussing on the digitalization and the application of modern technology to enhance student experiences in the didactics of physics.


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