Food For Thought: Solid Liquid Gas Plasma Cake

摘要

If you ask chemical engineering students about the phases of matter, they will happily tell you that things are solids, liquids, gasses (or, sometimes, plasmas, apparently the letter “y” of matter) and go on to give you practical definitions of the same. And if you ask how substances tend to transform, students will add with absolute confidence that it’s nearly all about temperature - at low temperature, materials are solids, and as you go upwards they tend to become liquids then gasses, although at some pressures for some substances, sometimes you do not pass liquid (or collect $200) and go straight to gas. But a place where this all goes sideways is when you ask the same students what phase “cake” is.