A science history exhibition currently on view at the museum is “Great Women, Great Science,” which runs through April 10, 2005. “The show focuses on four pioneers who overcame great barriers to make major contributions in the first half of the twentieth century,” says science curator Carolyn Rebbert. They include Marie Curie, the two-time Nobel prize winner and discoverer of radium; Annie Jump Cannon, an astronomer at Harvard University Observatory who came up with a new system of star classification based on her analysis of stellar spectra; Inge Lehmann, a Danish geophysicist who discovered that the liquid core of the earth has a solid innermost core; and Barbara McClintock of Long Island’s Cold Spring Laboratory, who received a Nobel prize for her work in genetics. Visitors can explore the scientists’ discoveries through hands-on activities, and their lives through a collection of personal objects, scientific instruments, photographs, and video clips.On March 6, 2005, Professor Maria Luisa Crawford will be speaking on people as agents of geological change. Crawford is chairman of the geology department at Bryn Mawr College and in 1993 received a MacArthur (“genius grant”) Fellowship. Dr. Kathie Olsen, associate di-