Space-Filling Molecular Models

From the 1860s, chemists have used three-dimensional models as aids to teaching and research. Many early models resembled Tinkertoys, with balls representing atoms and connectors signifying chemical bonds. From the 1930s, some research chemists and molecular biologists found it more useful to represent atoms by large, space-filling spheres or other shapes, as this better mimicked their physical properties. Such space-filling models were developed by scientists Robert B. Corey, Linus Pauling and Walter Koltun. They sold as CPK models, after the initials of their names.
Representing chemical bonds appropriately was important to the teaching reform efforts of the 1960s. However, CPK models were too expensive for most classrooms. The Wisconsin firm of Science Related Materials sold these molded polystyrene space-filling molecular models both for research and classroom use.
A complete version of this kit included 60 color-coded atomic units, a package of connectors, a ruler with dimensions indicated in Angstroms, and an instruction booklet. Schools and colleges that purchased SRM Molecular Fragments could receive matching funds from the U.S. government.
Currently not on view
Object Name
molecular model kit
overall: 2 1/4 in x 12 in x 9 in; 5.715 cm x 30.48 cm x 22.86 cm
ID Number
accession number
catalog number
Science & Mathematics
See more items in
Medicine and Science: Chemistry
Data Source
National Museum of American History, Kenneth E. Behring Center

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