NAME: Galileo Motion Data TYPE: Measurement SIZE: 7 observations, 2 variables (both numeric) 5 observations, 2 variables (both numeric) DESCRIPTIVE ABSTRACT: This dataset consists of data taken by Galileo in an attempt to model the path taken by projectiles. The first dataset was obtained in an experiment in which Galileo rolled a ball down an inclined plane. The plane was situated above the floor. He recorded the height at which he released the ball and the distance the ball traveled before landing. The second dataset was obtained similarly, with the difference that the ball crossed a horizontal shelf built into the end of the ramp. This shelf had the effect of cancelling out the downward force vector operating on the ball before freefall. SOURCE: Drake, Stillman (1978), _Galileo at Work_, Chicago: University of Chicago Press. VARIABLE DESCRIPTIONS: Columns 1 - 4 Horizontal distance traveled 6 - 9 Release height above table SPECIAL NOTES: The two datasets are separated in the file by a row of zeros. The variables are the same; only the method of obtaining the data differs. Both variables are measured in units of punti (points). STORY BEHIND THE DATA: Galileo was interested in the physical forces acting on projectiles for both scientific and military (artillery) reasons. An article in the _American Scientist_ (Jeffreys and Berger 1992) used the data to describe the utility of Ockham's razor. PEDAGOGICAL NOTES: Information on the pedagogical uses of these data can be found in the "Datasets and Stories" article "Teaching Statistics With Data of Historic Significance: Galileo's Gravity and Motion Experiments" in the _Journal of Statistics Education_ (Dickey and Arnold 1995). REFERENCES: Dickey, D.A., and Arnold, J.T. (1995), "Teaching Statistics With Data of Historic Significance: Galileo's Gravity and Motion Experiments," _Journal of Statistics Education_, 3, No. 1. Jeffreys, W.H., and Berger, J.O. (1992), "Ockham's Razor and Bayesian Analysis," _American Scientist_, 80, 64-72 (Erratum, p. 116). SUBMITTED BY: David A. Dickey Department of Statistics, Box 8203 North Carolina State University Raleigh, NC 27695-8203 dickey@stat.ncsu.edu