# Dissected Cylinder Transformable into Block

Usage conditions apply
Description
In the years following the Civil War, a handful of American educators designed and sold wooden solids or flat shapes hinged or doweled so that they could be transposed into other shapes that had areas known to students. One such educator was Albert H. Kennedy (1848–1940), superintendent of schools in Rockport, Indiana. He sold this business to the Rockport School Desk Company. Modified forms of the solids were later offered by the Western School Supply House of Des Moines, Iowa, A. Cowles and Company of Chicago, Illinois, and the American School Furniture Company of Chicago.
This model is a generalization on Kennedy’s model showing the area of a circle, applied to the problem of finding the volume of a cylinder. The cylinder consists of two semicylindrical portions. Each portion is divided into eight equal wooden segments, which are held together by two pieces of cloth tape that are nailed around the circumference. Rearranging the pieces gives a rough block that has one side equal to half the circumference of the circle, one side height equal to the radius, and one side equal to the height of the cylinder. Multiplying the three factors together gives the desired volume.
The object has no maker's marks.
Compare 2005.0054.01, 2005.0054.02, 2005.0054.03 and 2005.0054.04.
References:
Arithmetic of Practical Measurements for Teachers' Instruction and Class Work in Mensuration. Published by Western School Supply House, Des Moines: Iowa Printing Co., 1893. This reportedly was ”To accompany Kennedy’s improved dissecting mathematical blocks. 20th ed.” A copy of the sixteenth edition, which has the same date, is 2005.3099.01.
“Paintings Presented to Local Schools,” Rockport Journal May 15, 1964.
Location
Currently not on view
Object Name
geometric model
ca 1900
maker
Kennedy, Albert H.
Physical Description
wood (overall material)
cloth (overall material)
metal (overall material)
Measurements
overall: 10 cm x 10 cm x 10 cm; 3 15/16 in x 3 15/16 in x 3 15/16 in
ID Number
2005.0054.02
catalog number
2005.0054.02
accession number
2005.0054
Credit Line
subject
Mathematics
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Arithmetic Teaching
Data Source
National Museum of American History
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