Galileo and Experimental Research

  “Galileo and Experimental Research” was itself an experimental prototype project of the Institute and Museum of the History of Science of Florence, backed by the European Pencil Project (Permanent EuropeaN Resource Centre for Informal Learning) for the academic year 2005/06.

The idea

  The basic idea came from a reflection on the ways in which a museum of the history of science could contribute to informal learning in the sciences.  It seems more or less natural to try to expand the historical dimensions of a given topic, perhaps concentrating on one of the more important periods, that of the scientific revolution in the early seventeenth century.  With that in mind we chose to focus on Galileo’s own early investigations of the properties of “natural” motion, the work which led him to find, among other things, the “his own”  laws of free fall in their initial formulations, before they became subsumed under classical, Newtonian mechanics.  We wanted to present scientific research not as a clean straight path to the obvious, but as winding road of questioning, testing, making errors and then correcting them, in other words an evolving physical/mental conversation with nature.

The cultural setting forming the background of this project

  Naturally enough, Galileo began his investigations with what he had been taught concerning motion by the professors of philosophy, more or less Aristotelian, at the university of Pisa.  Very soon, however, he found that those accounts did not square with physical reality, that is with the physical reality revealed by precise and directed observation.  With this beginning and over a period of time, he refined the research, using physical and mathematical models and inventing equipment and means of precise measure, in a non linear, dynamic process of  trials, errors and corrections (including the incorporating of materials from related studies) finally to reach “his” laws of free motion.  We have traces of these laws in the first decade of the 17th century; they were presented in final form in his Discorsi on Two New Sciences in 1638.  In that work Galileo integrated the laws of free fall with those of the isochronism of pendula and  the trajectories of projectals and provided the intermediate results of his investigations into musical acoustics.
  In short, Galileo went far beyond the “ancient” theories he had inherited by developing a style of explorative research involving both the creation of new physical means and new mental (mathematical) models for accommodating his results.

Structure of the project

  The project was planned by a working group comprising an historian of science and two experts in science communication.  In addition, the actual realization in the classes involved an individual we called a “facilitator”, in this case a doctoral student in astrophysics with solid experience in the presentation of difficult topics to untrained audiences; she was to act as a prod to the members of the classes (see below).
  In preparation for the actual “experiment” the working group held several meetings, among other things choosing 19 school teachers who would participate along with their students; these were selected on the basis of their evident motivation and desire plus their willingness to work under our defined ground rules.  They would bring 15 school classes to the Museo: 12 at the “upper middle” level and 3 at the “lower”, for a total of 283 students.
  In the fall of 2005, during the first part of the academic year, we held two meetings with the teachers in which we filled them in with the historical background against which Galileo began his own experimental researches, in part drawing their attention to the existence of the strong engineering, high-tech tradition in Florentine/Tuscan culture during the later middle ages and renaissance.  The initial group of teachers was made up mostly of instructors of mathematics and physics but included one in “letters”.  Eventually teachers in other, non scientific disciplines were added in order to increase the interdisciplinary nature of the effort.
  The actual meetings with the students took place in February and March.  Each class met at the Museum for one session, two hours long.  In the late spring of 2006 we held two meetings with the teachers in order to gather their own reactions and evaluations along with those of their students.  During the course of the year the working group remained always available to the teachers to provide whatever help or further information they might need.

Structure of the actual class sessions

  Our facilitator began each of the sessions by giving the students a brief introduction to the world into which Galileo was born, including some aspects of the dominant philosophical views about nature.  They were told that they would be investigating some of these ideas and  that they would have available to them a collection of objects and tools gathered in a large container in the room.  They were then asked a few questions which were designed to elicit their own naive (initial), common sense notions of how things work.  Since most of the students had had no solid exposure to modern scientific “truth”, their answers often closely resembled those of Aristotle.  Our task was to prod the students, in a Socratic sort of way, to move beyond what appeared to them as obvious, for instance about free fall, and to think about how they might go about seeing if their ideas actually conformed to reality.  In fact, the elements of modern (Newtonian) mechanics are by no means obvious, despite what college instructors often say; and what we wanted to do was to provide the students with some notion of the difficult path between Aristotle’s physics and Galileo’s early achievements along with an example of the often non-linear, chancy nature of actual research.
  In particular the students were given a brief version of Aristotle’s theories of motion, including the idea that a body’s speed in free fall was proportional to its weight.  They were then asked to find ways to test whether this was actually the case.  They quickly mastered this problem and some even found Galileo’s temporary result to the effect that when two balls were dropped the lighter one precedes heavier.  And most moved on to experimenting on an inclined plane using a sort of Galilean water chronometer.
  At a more general level, the task of the facilitator was to goad the students by posing pertinent questions and to answer questions on their part but never to anticipate the “correct” solutions.  The students were therefore free at each step to imagine many possibilities but were constrained to examine their ideas critically, testing their reasoning and testing their
suppositions empirically.  In this way the students became active participants in the work and not just passive receptors of truths.  Very quickly they entered into the spirit of the enterprise, eventually to “rediscover” some of Galileo’s early results.

The working group for the project:
Silvana Barbacci, Annalisa Bugini, Thomas B. Settle

The facilitator:
Guia Pastorini

The teachers and their classes: the participants in the project:

[*] The students of this class (from the ITI Leonardo da Vinci) who were specializing in photography did a video documention of their session and put the results on a DVD.

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