Question on Capillary action?

The capillary action has to do with the polarity of the solvent used and the polarity of what you have on the TLC plate. When a polar solvent is used the fumes fill the jar and help carry you'r sample on the TLC plate up to the top. The polar molecules then separate and travel up the plate, the most polar molecules travel further than the least polar molecules and the non polar stay behind, which then separates all the different substances in the sample you have put on the bottom. If you put a non polar solvent in then the non polar molecules will travel further, the total opposite happens.