Key issues in the design of science facilities used by grades nine through twelve are presented and analyzed in this extended discussion. Four basic determinants of educational specifications are given as--(1) gross activities and sub-group organization, (2) number of students in the space, (3) services required, and (4) location in relation to school building and site. A procedural planning model is presented which relates goals, methods and facilities. The discussion is based on definition of goals, determination of methods including wet and dry labs, verifying and inquiry experiment, directed and undirected study, and specification of facilities and services. Conclusions relate to methods of determining educational specifications and approaches to planning and research. (MM)