One theoretical approach for increasing intrinsic motivation for reading consists of teachers using situational interest to encourage the development of long-term individual interest in reading. The authors investigated that possibility by using stimulating tasks, such as hands-on science observations and experiments, to increase situational interest. Concurrently, the authors provided books on the topics of the stimulating tasks and teacher guidance for reading to satisfy curiosities aroused from the tasks. Students with a high number of stimulating tasks increased their reading comprehension after controlling for initial comprehension more than did students in comparable intervention classrooms with fewer stimulating tasks. Students' motivation predicted their level of reading comprehension after controlling for initial comprehension. The number of stimulating tasks did not increase reading comprehension on a standardized test when motivation was controlled, suggesting that motivation mediated the effect of stimulating tasks on reading comprehension. Apparently, stimulating tasks in reading increased situational interest, which increased longer term intrinsic motivation and reading comprehension. (Contains 4 tables and 1 figure.)