This question might involve too much current for an electronic engineering board, but it involves electricity, so I'll ask it anyway.
YouTube videos of the railgun https://www.youtube.com/watch?v=ZL4kbBIf39s show a curious phenomenon; billowing clouds of what appear to be flame emerging from the barrel. Those are understandable from conventional cannon, because there is combustion continuing after the projectile leaves the tube, but railguns don't use combustion.
What's going on? They're far too fractal to be supersonic shock waves. Are they plasma, glowing atmosphric gases that have been heated by compression in front of the projectile, or something else?
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Are the design challenges the same as with embedded systems, but with a little developer- and IT-skills added in? What do engineers need to know? Rick Merritt talks with two experts about the tools and best options for designing IoT devices in 2016. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.