The "Sonic Boom, Sound Barrier, and Condensation Clouds" tutorials by Dr. Mark S. Cramer (professor over at the Virginia Polytechnic Institute and State University - http://www.vt.edu) are sufficiently non-technical, reasonably easy-to-grasp, and apparently written for a wide audience, that I'm hoping the high school and college students who are studying or are interested in this subject will drop by General Discussion forum to learn about this useful homework (and teaching resources). Go to the tutorials on his Fluid Mechanics site, FluidMechan.com , and look for Sound Barrier, or just click here (http://fluidmech.net/tutorials/sonic/sonicboom-intro.htm). The Sonic Boom, Sound Barrier, and Prandtl-Glauert Condensation Clouds (P-G Clouds, Prandtl-Glauert singularity clouds) tutorials are listed there. They say a picture is worth a thousand words, so where can you find the mouth-dropping Prandtl-Glauert condensation clouds pics? Start at the links below (and read the explantion here): http://www.GalleryOfFluidMechanics.com/conden/pg_sing.htm (Dr. Cramer's Prandtl-Glauert condensation cloud photo gallery at GalleryOfFluidMechanics.com) http://ChamorroBible.org/gpw/gpw-20040817.htm http://ChamorroBible.org/gpw/gpw-20040818.htm http://www.wilk4.com/misc/soundbreak.htm (also has beautiful very high-res images of Bobbi Garcia's photo of the B-2 "Stealth" bomber with the P-G condensation cloud) Enjoy!