1. The problem statement, all variables and given/known data The critical point is defined as : At the critical point there is no change of state when pressure is increased or if heat is added. At the critical point the water and steam can't be distinguished, and there is no point referring to water or steam. 2. Relevant equations 3. The attempt at a solution I guess I'm trying to get an intuitive feel for what that means. Hypothetically, suppose I could hold a transparent container full of a substance at the critical point. (without burning myself) What would I see? Would it appear as vapor? Is it not possible for water to exist as a liquid at such extremes? This may sound like a silly question, but something about the definition doesn't sit right with me.