I'd like to do a class experiment as a metaphor for human relationships. Two people each have a different chemical which evaporates quickly (at STP). There is one glass between them. If only one person pours his/her chemical into the glass, it quickly evaporates. However, if both pour equal portions of their respective chemicals into the glass, it is a stable mixture which can fill the glass and not evaporate.
Are there two such chemicals that will do this?