Harvard Project Physics epicycle demonstration device
Date: 1962-1972
Inventory Number: 2006-1-0079
Classification: Demonstration Apparatus
Attributed to: Damon Engineering, Inc. (fl. 1962 - 1972)
Maker: Harvard Project Physics (1962-1972)
User: Harvard College (founded 1636)
Cultural Region:
Place of Origin:
Dimensions:
25 × 51 × 23 cm (9 13/16 × 20 1/16 × 9 1/16 in.)
Material:
wood,
DescriptionThe main body of this epicycle demonstration apparatus is a long, rectangular bar of wood. The leftmost end of the bar is raised and attached to the half way point on a smaller, rectangular wooden bar. The attachment is made with a pivot and a white plastic gear (such that the wooden bar will rotate when the gear turns).
Also at the leftmost end of the main bar, there is a metal screw going through the wood, with a white, plastic gear on the bottom that is interconnected with the gear attached to the smaller wooden bar. A round, wooden, three-tiered disc is attached to the inner most screw -- its motion being transferred to the white plastic gear below. The disc is tiered such that the top most circle is the largest and the bottom most circle is the smallest.
There is a second three-tiered wooden disc attached by a screw at the center of the main wooden bar. It is tiered such that the top most circle is the smallest and the bottom most circle is the largest. There is a thin wooden bar extending from the center of this tiered disc, perpendicular to the main wooden bar. Attached to the top with a small screw, there is a handle with a crank extends parallel to the main bar. There is a black rubber band hooked over both wooden discs. It can be placed on the top, middle, or bottom of the three tiers on each disc.
The right most end of the main bar is bracketed with a metal plate on either side, attached by two screws.
Also at the leftmost end of the main bar, there is a metal screw going through the wood, with a white, plastic gear on the bottom that is interconnected with the gear attached to the smaller wooden bar. A round, wooden, three-tiered disc is attached to the inner most screw -- its motion being transferred to the white plastic gear below. The disc is tiered such that the top most circle is the largest and the bottom most circle is the smallest.
There is a second three-tiered wooden disc attached by a screw at the center of the main wooden bar. It is tiered such that the top most circle is the smallest and the bottom most circle is the largest. There is a thin wooden bar extending from the center of this tiered disc, perpendicular to the main wooden bar. Attached to the top with a small screw, there is a handle with a crank extends parallel to the main bar. There is a black rubber band hooked over both wooden discs. It can be placed on the top, middle, or bottom of the three tiers on each disc.
The right most end of the main bar is bracketed with a metal plate on either side, attached by two screws.
Signedunsigned
Inscribedgreen label stuck to main arm of instrument: SCI CEN NS-7
FunctionThis apparatus is used to demonstrate the Ptolemaic concept of an epicycle. Ptolemy employed the epicycle to explain planetary retrograde motion while still restricting the motion of the planets to Aristotle's criteria of perfect circular motion.
In order to demonstrate an epicycle, users turn the crank attached at the center of the main bar. Turning the crank causes the central wooden disc to rotate, transferring its motion to the black rubber band, which in turn rotates the inverted wooden disc at the leftmost end of the main wooden bar. When that disc turns, the white plastic gear beneath it also turns, transferring its motion to the second gear and in turn to the wooden bar attachment at the left most end of the main bar. The attachment will be made to rotate and the circumference of the rotation is the epicycle. When the main wooden bar is also made to rotate (either manually or by attaching the device to a turntable) with its rightmost end at the center of rotation, the motion of the wooden extension on the leftmost end will mimic that of an orbit combined with an epicycle.
In order to demonstrate an epicycle, users turn the crank attached at the center of the main bar. Turning the crank causes the central wooden disc to rotate, transferring its motion to the black rubber band, which in turn rotates the inverted wooden disc at the leftmost end of the main wooden bar. When that disc turns, the white plastic gear beneath it also turns, transferring its motion to the second gear and in turn to the wooden bar attachment at the left most end of the main bar. The attachment will be made to rotate and the circumference of the rotation is the epicycle. When the main wooden bar is also made to rotate (either manually or by attaching the device to a turntable) with its rightmost end at the center of rotation, the motion of the wooden extension on the leftmost end will mimic that of an orbit combined with an epicycle.
Historical AttributesThis apparatus was designed to be used with Project Physics, a national physics curriculum developed in the 1960s. Project Physics materials included teaching aids, apparatus for student experiments, and books.
The Project Physics Course grew out of a Harvard University initiative to teach all students physics, not just those who would go on to careers in science. The course aimed to be a "humanistically oriented" introduction to "science at its best."
Damon Engineering produced and marketed a set of Project Physics laboratory equipment in coordination with the curricular work of Harvard physics professor Gerald Holton, California high school science teacher F. James Rutherford, and Harvard Graduate School of Education professor Fletcher G. Watson.
This instrument is marked "NS-7." This refers to a General Education (Gen Ed) course, Natural Sciences 7, which was colloquially known as Nat Sci 7. Nat Sci 7 was a physics course for non-scientists first taught by Gerald Holton in 1966. It was part of the newly established General Education curriculum at Harvard. Holton was vice-chairman of the Faculty Committee on General Education and Holton designed Nat 7 as a model course to "make science irresistible" and improve the public image of physics.
The Project Physics Course grew out of a Harvard University initiative to teach all students physics, not just those who would go on to careers in science. The course aimed to be a "humanistically oriented" introduction to "science at its best."
Damon Engineering produced and marketed a set of Project Physics laboratory equipment in coordination with the curricular work of Harvard physics professor Gerald Holton, California high school science teacher F. James Rutherford, and Harvard Graduate School of Education professor Fletcher G. Watson.
This instrument is marked "NS-7." This refers to a General Education (Gen Ed) course, Natural Sciences 7, which was colloquially known as Nat Sci 7. Nat Sci 7 was a physics course for non-scientists first taught by Gerald Holton in 1966. It was part of the newly established General Education curriculum at Harvard. Holton was vice-chairman of the Faculty Committee on General Education and Holton designed Nat 7 as a model course to "make science irresistible" and improve the public image of physics.
Primary SourcesThe Project Physics Collection of course books is archived online here.
Linda J. Greenhouse, "Gerald Holton: The Discovery That Scientists Are Also Philosophers Should Not Depend On Accidents," The Harvard Crimson, December 12, 1966; found online here.
Linda J. Greenhouse, "Gerald Holton: The Discovery That Scientists Are Also Philosophers Should Not Depend On Accidents," The Harvard Crimson, December 12, 1966; found online here.
ProvenanceScience Center Physics Lab