This video explains that rust is an electrochemical reaction that occurs when steel is exposed to oxygen, water, and salt, essentially creating a weak acid that corrodes metal. Modern cars combat this through a multi-layered paint system—primer, base coat, and clear coat—which acts as a protective barrier, and electroplating with zinc for structural components, as zinc sacrificially corrodes before the steel. The key to preventing rust, therefore, is to maintain these protective coatings, regularly waxing the car to keep the clear coat flexible and immediately sealing any scratches with clear coat. For areas prone to damage like the undercarriage, specialized rust-preventative paints can be applied even over existing surface rust to create a new protective layer, ultimately preventing the bare metal from undergoing electrochemical oxidation.