Physical geographers study the variations in climates, vegetation, soil, and land forms, and their implications for human activity. Urban and transportation geographers study cities and metropolitan areas, while regional geographers study the physical, economic, political, and cultural characteristics of regions, ranging in size from a congressional district to entire continents. Medical geographers study health care delivery systems, epidemiology, and the effect of the environment on health. Historians research, analyze, and interpret the past. They use many sources of information in their research, including government and institutional records, newspapers and other periodicals, photographs, interviews, films, and unpublished manuscripts such as personal diaries and letters.
Biographers collect detailed information on individuals.
Genealogists trace family histories. Other historians help study and preserve archival materials, artifacts, and historic buildings and sites. Political scientists study the origin, development, and operation of political systems and public policy. They conduct research on a wide range of subjects such as relations between the United States and all other countries, the institutions and political life of all nations, the politics of small towns or a major metropolis, or the decisions of the U.S. Supreme Court. Studying topics such as public opinion, political decisionmaking, ideology, and public policy, they analyze the structure and operation of governments as well as various political entities.