Lecture, two hours; laboratory, four hours. Requisites: courses 105B, 110B, 112 (or Astronomy 115), 115B. Prior experience in working with computers is helpful but not required. Designed to give first-hand experience in solving physics and astronomy problems on computers. Project-based course, with projects selected from core areas of classical mechanics, electrodynamics, quantum physics, statistical physics, and astronomy. Introduction to problems and to required numerical methods in lectures, so students can write programs in one modern programming language of their choice (Python recommended) and carry out numerical experiments with it, with results documented in reports. P/NP or letter grading.