Upon completion of this webinar, you will be familiar with how a given physical process be simulated on a computer efficiently. Reliably complicated; physical phenomena are subtle and intricate, and modern computer systems sophisticated. The details of how best to achieve efficient simulation for even apparently similar phenomena - for example, the motion of waves in the ocean, and the wake from a powerboat - vary greatly, and the evolving state of computing environments adds an additional dimension of complexity to the matter. Computer environments today are rife with performance-minded features - everal varieties of parallelism among them - and any efficient realization of a physical process on these contemporary systems must account for these features at some level. In this talk, we explore a real-world scientific code for gas dynamics that delivers useful and correct results, but with (initially) unsatisfactory performance. By examining what the code implements and seeing how it may be mapped to modern architectural features, we will see its performance improve dramatically.