This post describes two related projects: the astro-lab@home, published in CAPjournal in 2022 with Alexander Küpper and André Bresges; and its successor, the astro-lab@school, published the same year in Astronomie+Raumfahrt. Both grew from the same question: what does astronomy education look like when you cannot bring students into a lab?
What the astro-lab Was
Before the pandemic, the astro-lab at the University of Cologne was a student laboratory focused on extrasolar planets. School groups — mostly secondary school students — came in and worked through a set of analogy experiments: how do you detect a planet you cannot see? How do you infer its size, its orbit, whether it might be habitable?
The pedagogical bet was that exoplanet research, precisely because it is headline-generating and genuinely open-ended, could counteract the motivational slump in physics that tends to set in around middle school. The context — life in the universe, habitable worlds, the possibility of something out there — did a lot of the work that no abstract force diagram could do.
The experiments themselves were analogy experiments: a lamp standing in for a star, a sphere on a track standing in for a planet. The key measurement was the transit: when the “planet” passed in front of the “star”, the light sensor registered a dip. Students measured the dip, estimated the ratio of areas, connected it to radius, and got a number that meant something. The number was not precise. It did not need to be. It was real.
Spring 2020
In March 2020, schools shut down, and the University of Cologne followed. Visits to the astro-lab were cancelled. The question the team faced — Alexander Küpper, André Bresges, and I — was not whether to do something but what was actually feasible.
The project article cited a German pandemic survey in which 16% of the sampled students reported video conferences with teachers and 30% reported no contact since the initial shutdown. Those figures describe that survey and period, not every German learner. The infrastructure was not there, the habits were not there, and the expectation that students had the materials and equipment for a physics lab at home was not warranted.
Smartphones were widespread, but access was not universal and did not guarantee that a required sensor was present or exposed to an app.
Smartphone models expose different combinations of sensors, which may include ambient light, acceleration, rotation, pressure, and magnetic-field sensors. The app phyphox, developed at RWTH Aachen, makes those sensors accessible with a clean interface designed for use in education. If the sensor hardware was already in students’ pockets, the lab setup problem became: what household materials can stand in for the rest of the apparatus?
astro-lab@home: Bringing Science to the Sofa
The astro-lab@home project adapted the original lab experiments for home use with smartphones and everyday materials. The core transit experiment — measuring the dip in light caused by an opaque object passing in front of a lamp—was demonstrated with household equipment and compatible phones. The publication is an implementation report, not a multi-site replication study. A table lamp, a ball on a string, and a smartphone positioned beneath the lamp gave you the raw data. phyphox recorded the light curve in real time.
We designed the setup to be flexible enough to work with what students actually had. The default used an ambient-light sensor on compatible Android devices. The phyphox App Store build cannot access the iPhone’s physical light sensor, so the project recommended an external sensor. Cost, compatibility, calibration, and cross-device consistency depend on the chosen hardware and must be checked rather than assumed.
The resulting package was not just an equipment list. We developed accompanying materials that explained the physics (why does a transit produce a specific shape of dip rather than a sharp cutoff?), connected the analogy experiment to the real science (how does this scale up to the actual transit photometry done by TESS and Kepler?), and offered scaffolding at different levels of independence.
The project was published in the IAU’s CAPjournal in 2022 — a journal aimed at communicators and educators in astronomy. The audience was intentionally broad: teachers looking for accessible classroom activities, outreach organisations trying to reach students at home, curious individuals who wanted to do something real with their phone. “Bringing science to the sofa” was the headline, and that was genuine. The experiments worked in a living room.
What Came Next: astro-lab@school
When schools reopened and in-person teaching became possible again, the question was not simply “back to normal” but what the COVID period had actually taught us about the format.
The astro-lab@school, published in Astronomie+Raumfahrt in 2022, addressed that question directly. Some design features from the home version were retained. The team judged the smartphone setup portable and useful for student control of the apparatus. The publications do not provide a controlled cost comparison or establish that using a personal device improves learning.
The astro-lab@school retained the smartphone-centred approach and adapted it for a school context: class sizes, time constraints, the reality of mixed equipment across a room of thirty students. The experiments from the home version were modified for group work and parallel execution. The scaffolding materials were reworked for the paced structure of a school lesson rather than the self-directed format of home use.
The result was not a reversion to the pre-pandemic lab. It was a hybrid: in-person group work, but with tools and methods developed for distributed individual use. The pandemic had pushed the format toward a different, more distributed design; “more robust” remains an engineering judgment rather than a measured outcome.
A Note on What Made This Work
The core technical contribution — smartphones as measurement instruments for analogy experiments in astronomy education — is described in more detail in a later publication in The Physics Teacher, which covers the experimental setups, sensor comparison, and pedagogical progression in a form aimed at an international teaching audience. If you want the how-to, start there.
What I want to note here is something slightly different: the role of context.
The astro-lab used exoplanets as a motivational context. The cited project record does not quantify motivation or compare exoplanets with other physics contexts, so I retain that choice as a design judgment rather than an effect claim. The COVID period showed that the team could implement the context without the university lab infrastructure. Students working on transit photometry with a lamp and a smartphone in their kitchen were doing the same thing, conceptually, as students at a benchtop sensor station at the university. The physical setup was different. The question was the same.
My narrower lesson is that this context survived one redesign. That does not prove that context-driven education is independent of material configuration.
For the curriculum unit that places these experiments in the context of the NRW Sekundarstufe I physics syllabus, see Fremde Welten. For the air pressure / Mars experiment that grew from the same lab, see Mission to Mars.
Project and literature record checked through 2026-07-11.
Changelog
- 2026-07-11: Bounded pandemic survey figures to their sample; corrected smartphone and iPhone sensor claims; and separated the published implementation from unmeasured replication, cost, robustness, motivation, and learning-outcome claims.
References
Spicker, S. J., Küpper, A., & Bresges, A. (2022). astro-lab@home — bringing science to the sofa. CAPjournal, 31, 12–17.
Küpper, A., & Spicker, S. J. (2022). astro-lab@school. Astronomie+Raumfahrt im Unterricht, 59(6).
Küpper, A., & Schulz, A. (2017). Das Schülerlabor astro-lab an der Universität zu Köln. Astronomie+Raumfahrt im Unterricht, 54(1).
Stampfer, C., & Staacks, S. (2020). phyphox — using smartphones as experimental tools. Physics Education, 55(5), 055007. https://doi.org/10.1088/1361-6552/ab8a2e