Water molecules are polar because they have positive and negative ends, rather like little magnets. Most lipids are non-polar (having no charged areas) or only slightly polar, with a very few charged areas. Since lipids have no charged groups, the water molecules have nothing to stick to and dont mix with them.
A feather floating through the air has more kinetic energy because the rock is not in motion its on the ground the feather is moving in the air at a pretty fast rate of speed.
