Measure the duration of a free fall using your smartphone and the acoustic stopwatch in phyphox.
I hope you enjoyed our science night at the RWTH Aachen University and attended our smartphone experiment talk or visited us at our phyphox booth. But even if you did not attend our science night, you might still enjoy playing with a new tool…
Right at the beginning of the science night there was a big science slam which used phyphox as an applause meter to assign scores to the contestants. So, here it is – Simply open the following link on your phone with phyphox installed and it should automatically launch in our app:
Just a few things to keep in mind if you want to use it in an actual competitions:
- Scores varying across different phones, so you should use the same phone to judge all contestants.
- Do not place the phone too close your audience as close sounds register much louder. Often a place quite central on stage is a good choice. Always evaluate the applause from the same place and orientation of the phone.
- The score will be proportional to the integral of the RMS of the recording. In other words, you will get higher scores for louder and longer applause – It adds up continuously at a rate that depends on the volume of the applause.
It’s been more than a week since we held a workshop on academic teaching with phyphox for the first time. I picked the phrase “for the first time” with intent because this workshop has been a huge success and it is quite likely to be held again in the future.
A total of 25 participants from the RWTH Aachen University and a whole range of German educational institutions gathered to learn about ways to use phyphox in lectures and associated exercises. There was not just an introduction to the app and a presentation of our use of phyphox in physics lectures at RWTH Aachen University, but also hands-on experiences for experiments and our experiment editor as well as discussions on the future of phyphox.
LEIFIphysik is a well-known German web platform, which offers a huge range of ressources for teachers – and phyphox is now used in several experiments (in German) presented on their website.
So, the folks at PhoneLabs sent me one of their Starter Kits to play with. This is a set of 3D printed parts along with some skrews and a rod that are designed to assemble into a simple setup for smartphone experiments.
The only thing that you need to add (besides your smartphone) is a ruler. Unfortunately, all rulers I tried were either too wide or too short, so I had to resort to a folding rule, which is not ideal because of the bulky folded part on one side, but still worked quite nicely.
As you can see from the video, I decided to try out our centripetal acceleration experiment and used our remote access to view the data on a laptop PC while rotating the phone. If you don’t know this experiment, here is the video, explaining the setup using a salad spinner:
The advantage of the 3D-printed setup over the salad spinner is, that you can vary the radius of your motion. I simply did the experiment three times in a row for different radii, pausing and resuming my measurement in-between. Here is the result (screenshot from the remote interface) after three repetitions:
You can clearly see and compare the three slopes, following nicely.
By the way, PhoneLabs also offer their own apps. While these do not provide features like remote access, there is something quite unusual and novel about them as you do not need to be installed anything on your phone. In fact, they simply run in your web browser from where they can still access some of your phone’s sensors.
Since this is the English version of this article, I should probably start with an update on international events. After really enjoying the AAPT Summer Meeting in Cincinnati (that’s where the image above comes from), I intend to attend the AAPT Winter Meeting as well, which will be in San Diego, 6-9 January. I still have to submit abstracts and book flights, so this will be fixed and officially announced later this year.
There will also be a big workshop in Aachen on academic teaching with phyphox. If you are a college or university educator near Germany, this will be the event for you. However, it will be held in German and you will find more information here.
Additionally, there will be more events to be announced for Germany this year and next year. There are at least four public events, which are fixed and a few more planned, but I am waiting for the official release and/or schedule from the organizer.
Don’t worry, we are here to stay and I’d just like to communicate a few plans for the near future and address some details, which might confuse those who follow us closely. If you are just interested in being able to use phyphox as a free app, do not worry – everything is fine. If you are interested in some details, the team and our plans, read on…
First of all, let’s start with the change that might be confusing if not explained: I just got married and took the name of my wife. So, “Sebastian Kuhlen” is now “Sebastian Staacks”, but it’s still me and it is only a personal change for me, but absolutely no difference for phyphox.
Besides that, we are about to receive some help from our IT center and a new PhD student near the end of the year. While so far most of the development was done by myself (except for the much appreciated help from Jonas, a student who did a huge part of the iOS development at the beginning), there will be a software developer in training who will help for a few months and a PhD student, both working on a specific aspect of the app. Also, it is about time, that I update the “behind phyphox” section on the front page to also include those on the didactics front who have been there for a while now.
There will be even more help from people outside the RWTH Aachen University as many volunteered to translate phyphox at the GIREP conference in Dublin two weeks ago. If you want to translate phyphox to your language as well, I would be happy if you contact me. There are some requirements, though: First of all, be warned that there may be more text to be translated than you might expect and that just figuring out the right context may be more complicated than you might think. Also, you should be fluent in the language (ideally it is your first language) and you need to be a physicist in order to know the appropriate terms. Additionally, we require that you are a teacher at a school or university, so we can verify that you have a professional interest in translating. Finally, please be prepared on follow-up translations when new versions of phyphox introduce new text – this will not be much text and it will not occur too often, but it would be bad if we released new features and could not provide them in a language that we were able to provide before.
So, if you fulfill these requirements and I did not just scare you off, please contact me via the email address at the bottom of the page.
I have been promising this for a while now and as it happens so often, it took longer than expected. We intend to release the source code with the next major update (phyphox 1.1.0) or maybe its beta phase, so at that point anybody can contribute to its development. We just need to learn to develop the app as a team now and do not want to add to the confusion at this very moment.
Speaking of phyphox 1.1.0…
Another thing I have been promising for a while is better graphs, which should be included in phyphox 1.1.0 in a few months. Those graphs are still far from being ready, but here is a little teaser to prove, that I am working on it:
The other major features for the upcoming version will be Bluetooth support and a much more convenient way to transfer custom experiments from our editor to the app. However, development on this has not yet started, so I am a little hesitant to promise too much at this point – you will certainly hear about it, when things start to take shape.
We have just released a minor update with a handfull of bugfixes, especially addressing problems with the audio oscilloscope giving wrong data. In contrast to our regular updates, we push this one out on both systems as soon as possible since no features have been changed or added. Therefore the Android version should be available right now while the iOS version has to wait for Apple’s review process and is expected to be released until Friday.
Changes for both Android and iOS
- Fix wrong time axis of audio scope.
- Allow unusual frequencies in tone generator but add a warning.
- Rename centrifugal acceleration to centripetal.
Changes for Android
- Fix OK-button not accessible on startup (small screens with enlarged fonts)
- Fix rare crash in GPS module
- Combine wrong GPS status to “deactivated/active”
Changes for iOS
- Fix flickering of audio scope.
- Fix crash on audio playback, mostly on iOS11.
A few weeks ago, two students from the University of Salzburg have started to create short videos in which they present various experiments demonstrating the Doppler effect.
These videos will be presented by the Christian Doppler Fonds on christian-doppler.net and range from simple setups you can try at home to more involved ones which are well-suited for science classes in school. – and we are delighted that several of them use phyphox to determine the frequency shift using the Doppler experiment included in phyphox, which also calculates the corresponding velocity right away.
Unfortunately, these videos are only available in German, but if you are familiar with the Doppler effect, you should be able to easily follow their experimental setup just from the images. Here are some of the experiments using phyphox: