Phone physics and the Gateway Arch: Fun with friends and physics at the AAPT Winter Meeting in St. Louis

TL;DR

This paper explores physics concepts through a fun visit to the Gateway Arch, using phone accelerometers to measure gravity during the ride, and provides data and guides for educational use.

Contribution

It introduces a practical physics activity involving phone sensors at a landmark, with detailed data and teaching resources for educators.

Findings

Collected acceleration data during the tram descent.

Repeated measurements for accuracy and comparison.

Provided resources for classroom physics experiments.

Abstract

As a famous landmark and feat of engineering, the Gateway Arch was a popular destination at the 2025 AAPT Winter Meeting in St. Louis. The visit to the observation deck of the Gateway Arch is unique, climbing the steps after exiting the small tram capsules and seeing a floor that continues to slope upward assures that you are in fact at the very top. Everyone in our group excitedly took pictures, pointing out local features like the Dred Scott Courthouse. There were many selfies at the pinnacle, and we discussed how to work them into future questions for our students. During our tram ride to the top observation deck of the arch, we lamented that we should have brought pendula to measure the acceleration due to gravity. You can take physics teachers out of the physics conference, but you apparently can't get us to stop talking about physics teaching. Recognizing that we had accelerometers on our phones we collected data on the descent. The authors wanted to collect more complete measurements and returned two days later to repeat the journey, the results of which we present here. For readers wishing to repeat with their students, or who want to apply more advanced data analysis techniques, the authors have made the raw data, our spreadsheets, and a teacher's guide available.