The liquid metal, mercury, makes for dramatic demonstrations of density and buoyancy. You can, for example, float heavy objects such as a anvil in a sufficiently large container of mercury because its density is greater than that of lead. Some elements, however, are denser still, and objects made of elements such as tungsten, will sink in mercury. Who’s got that much mercury laying around? That’s a lot of thermometers. This amazing video is by Cody’s Lab. He’s a chemist YouTuber that has a ranch