Computers are becoming an increasingly cheaper, more powerful tool that cannot be ignored by professionals. Computer simulation reproduces the behavior of natural and man-made systems to help us understand, predict, and communicate. Vic Castillo, a research engineer at the Lawrence Livermore National Laboratory, shows how computer simulation is used by LLNL scientists on the world's fastest computers. See how you can get started doing your own computer simulations with free, open-source tools for class projects or just for fun. (#28463)