This is case study and demonstration lab. Safety scientists ask why a phenomenon happens. Safety engineers ask how they can solve the problem and keep people safe. Both ask how they can design and communicate solutions. The button cell battery is a case study in science and engineering for safety with a demonstration of how a small, single cell li-ion battery reacts with saliva to damage human tissue using saline and bologna. The classroom investigation can be done is small groups or as a demonstration for the whole class.