Designed to emphasize mathematics skills and science processes, this booklet contains activities which provide students of grades three and four with opportunities to explore and discover aspects related to geometry, structure, and measurement. Hands-on activities are presented on skyscrapers, bridges, bubble planes, and model structures. Eighteen mathematics skills and seven science processes are listed and indexed for the six activities on structures, nine activities on measurement, and the ten activities focusing on geometric concepts. Each activity consists of student sheets and a teacher's guide. The teacher's guide contains information on the activities including: (1) topic area; (2) introductory statement; (3) math and science skills; (4) required materials; (5) key questions; (6) background information; (7) management details; (8) instructional procedures; (9) student procedures; (10) discussion questions; (11) activity extensions; and (12) curriculum coordinates. (ML)