Greifswald 2024 – scientific programme

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GP: Fachverband Geschichte der Physik

GP 7: Instruments and Exhibitions

GP 7.2: Talk

Wednesday, February 28, 2024, 14:30–15:00, ELP 3: HS 2.33

's Gravesande's parabola - when motion becomes tangible — •Linnéa Bergsträsser — Institute of physics, its didactics and its history, Flensburg, Germany

In the 18th century, Willem Jacob 's Gravesande mentioned an apparatus that was supposed to visualise the flight path of a heavy body. A marble rolls down a ramp and exits in a horizontal direction. The interaction of this horizontal movement with the accelerating force of gravity creates the motion curve of the marble: The parabola. As this flight motion is far too fast for the human eye, 's Gravesande came up with an idea: first with steps, later with rings, he was able to visualise the marble's flight. This apparatus was a typical mechanical demonstration experiment from the 18th century.

At this time Galileis and Newtons mechanics were very popular and I will show the link between Galileis and Newtons mechanics and 's Gravesandes demonstration of motion.

At the Europa-Universität Flensburg, we have a reconstruction of the respective apparatus kept at the Museum Boerhaave. As part of my PhD project, I am working with this device and I analyse the accuracy of this demonstration experiment.

In working with this device, the key function of the instrument is that the ball moves through the rings. To ensure this, I had to learn to work with all my senses and not just trust my eyes. This was also the challenge for demonstrators in the 18th century. They needed to develop a certain way of dealing with demonstration experiments before they showing them to the students in the lectures.

Keywords: 's Gravesande; Parabola; Mechanics; Reconstruction