In 2023, researchers in South Korea claimed that a material called LK-99 was a superconductor that worked at room temperature and normal pressure. Superconductors carry electricity with no loss, but known ones must be kept extremely cold or under high pressure, so a room-temperature version would change many technologies. The claim spread rapidly, boosted by a video of a sample tilting up off a magnet.
Labs around the world rushed to reproduce the result. More than a dozen failed to see superconductivity, and several found LK-99 behaved like an insulator instead. The tilting was explained by ordinary magnetism, not the special effect superconductors show. A drop in resistance the original team reported was linked to a copper sulfide impurity that changes structure near 400 kelvin. The instructions for making the material were also hard to follow exactly.
By late 2023, scientists broadly agreed that LK-99 is not a room-temperature superconductor. The story is a useful lesson in how science works. A striking claim needs strong, independent evidence, and a single result that spreads online is a starting point for testing, not a confirmation.