Minimum Time, Maximum Effect: Introducing Parallel Computing in CS0 and STEM Outreach Activities Using Scratch

This paper presents our experiences and outcomes using Scratch to teach parallel computing concepts to students just learning about computer science. We presented versions of this material to middle school and high school girls during a STEM workshop and then to undergraduate university students enrolled in an introductory computer science course. Using the Scratch development environment, students are able to build, modify and observe the changes in the performance of applications which utilize multi-threaded, concurrent, operations. This includes scenarios which involve more advanced topics such as race conditions and mutex locks. Developing these materials has allowed us to introduce these concepts in a programming environment much earlier than we have previously, giving instructors in down-stream courses the ability to build upon this early exposure. Survey results show that this approach resulted in a significant increase in both of these areas. For example, the number of students in our CS0 course who felt they could apply parallel programming to other problems using Scratch more than doubled, rising from 25 to 55 (out of 61 students that responded to both surveys). Likewise, the number of students who felt they understood what parallel programming means rose from 27 to 56. These results were achieved after just one class period. Similarly, 27 of the 37 girls responding to the workshop survey felt that they were capable of learning to write computer programs and 22 of 41 indicated they had an interest in a job using HPC to solve problems.