In my opinion, LHP and RHP cannot be defined abstractly, in terms of just one aspect of the principles or aims of a particular path. Instead, I regard LHP and RHP as groupings that have evolved spontaneously, and whose meaning is mainly social and historical.
The cold plate causes the moisture in the warm air, which is inside the jar to condense and form water droplets. This is the same thing that happens in the atmosphere. Warm, moist air rises and meets colder air high in the atmosphere. The water vapor condenses and forms precipitation that falls to the ground.
Why does it rain? Warm air turns the water from rivers, lakes, and oceans into water vapor that rises into the air. That water vapor forms clouds, which contain small drops of water or ice crystals (depending on how high the cloud is and how cold it is).