This dissertation analyzes the U.S. science museum field over time in order to examine institutional emergence, institutional transformation, and changing patterns of science boundary-work in displaying "the natural world" to publics. It investigates the constitution of the U.S. science museum field via 19th century natural history museums and world's fairs, and the 20th century transformation of the field by industrial science museums and science center museums. Its theoretical contribution is to underscore the significance of material culture and its spatial dimensions to analyzing institutions, including patterns of boundary-work between publics and science. It argues that industrial science museums and their novel exhibitionary conventions arose as industrial material culture became framed as "applied science," and as distinct from artifacts in the existing field of natural history museums. In addition, it argues that science center museums distinguished themselves from and proliferated more rapidly than industrial science museums due not only to new constituencies mobilized on their behalf, but also due to their de-emphasis on collections, particularly of rare and historical artifacts. These changes again facilitated new exhibitionary conventions. Thus the emergence, transformation and proliferation of institutions hinge on their material cultural dimensions, on multiple levels.