A primary education specialist designed and implemented a 10-week practicum intervention intended to teach third-grade students how to tell time. Eight students who experienced considerable difficulty in telling time by 5- and 1-minute intervals participated in the study. Students learned to tell time through classroom and playground activities that involved use of a clock face made of cement stones built into the school's playground. While the intervention did not meet all objectives at the levels set, evaluation data indicated that in general the practicum was effective. During implementation, observation suggested that primary children need to work with large objects and pictures. Both mechanical and simulated clocks should be large so that children can easily see numerals and markings. Prominent among appended materials are the third grade mathematics program objectives, the county's standardized test on telling time, teachers' and students' surveys, pre- and post-tests, discussion questions and student responses, and directions for constructing the model clock and playing the Around the World game. A newspaper article, with photos of the playground clock, is also appended. (RH)