To earn additional income to support her large family, Gilbreth delivered numerous addresses to business and industry gatherings, as well as on college and university campuses such as Harvard, Yale, Colgate, the University of Michigan, MIT, Stanford, and Purdue University. In 1925 she succeeded her husband as a visiting lecturer at Purdue, where he had been delivering annual lectures. In 1935 she became a professor of management at Purdue's School of Mechanical Engineering, and the country's first female engineering professor. She was promoted to a full professor at Purdue in 1940. Gilbreth divided her time between Purdue's departments of industrial engineering, industrial psychology, home economics, and the dean's office, where she consulted on careers for women. In cooperation with Marvin Mundel, Gilbreth established and supervised a time-and-motion-study laboratory at Purdue's School of Industrial Engineering. She also demonstrated how time-and-motion studies could be used in agricultural studies and later transferred motion-study techniques to the home economics department under the banner of "work simplification". Gilbreth retired from Purdue's faculty in 1948.