DIY: Solar Thermally Pumped Hydroponic System

Interesting project with some physics to make it work (don't they all). I had to look up hydroponic, it is growing plants without soil. This solution uses perlite instead of soil.

How it works (this is my best guess). The bottom bottle holds the nutrients for the plant. Temperature change caused by passing clouds or day to night, cause water vapor and the nutrient to flow up into the top bottle (which holds the plant). The changing temperature creates thermal energy enabling a pumping system which, apparently, illustrates the "Ideal Gas Law" (still need to do a little more research on how this works).