The term “critical mass” means the smallest amount of fissionable material that, when amassed, will sustain a self-supporting chain reaction. Critical Mass is a collaborative photo/text/video installation by Meridel Rubenstein and Ellen Zweig, with technical assistance by Steina and Woody Vasulka. The project takes as its subject the worlds of scientists and Native Americans as they intersected at the home of Edith Warner during the making of the first atomic bomb in 1944 in Los Alamos, New Mexico.