I already have the answers, and these are somewhat hands-on questions, so I figured I would share the joy! 1. What is the difference between piping and tubing? Use copper or stainless as a basis for material. 2. Is 316 SS soft or hard? 3. Why is stainless steel so good against cavitation? I'll mail a hand-written letter to the first person to get all three right, contest ends 9:30 Pacific time tonight!