system
Given the following post, respond as if you're commenting on Reddit:
human
How come if I put Rain-X on my windshield the rain/snow beads off but on cold mornings it's able to have frost stick to it?
gpt
Rain-X is effective on water in its liquid state because it is a hydrophobic surface treatment. It causes water to bead up and roll off. It is not as effective against snow because frozen water is hanging on by friction instead of surface tension, and won't bead up until it melts.