Our Blob-a-Lamp is more than a mesmerizing motion light – it’s a complete lesson on density! At room temperature, the colored wax blobs are denser than the liquid. But turn the lamp on and soon enough, the questions begin: which material really is denser – the liquid or the wax blobs? What makes the blobs rise? Why do they then descend back toward the lamp’s base? And what does the incandescent bulb in the lamp’s base have to do with any of this? Students at all grade levels will be engaged by this retro object, and are sure to be eager to learn about heat, expansion and density. About 13″ tall. Colors may vary.