science
Most metals are rock-solid, but one was prized for centuries to fill thermometers because it flows like liquid silver.
Mercury stays liquid at room temperature because of unusual features in its atomic structure that weaken the metallic bonds holding its atoms together, giving it an unusually low melting point far below virtually every other metal. This made it valuable for thermometers and barometers, since its liquid form expands and contracts predictably with temperature, letting people read precise measurements.
Iron and aluminum are both solid at room temperature with much higher melting points, requiring intense industrial heat to melt, exactly why they're used for construction rather than fluid instruments.
Because mercury is highly toxic, most countries have phased it out of thermometers in favor of digital or alcohol-based alternatives, even though its unique liquidity made it prized for centuries.
science
How long can some snails stay asleep at a stretch?About how fast does light travel?Where does most of the mass of a growing tree actually come from?What makes the daytime sky look blue?What causes the Northern Lights (auroras)?About how fast does sound travel through air?About how much of our DNA do humans share with chimpanzees?What is the largest planet in our solar system?What do plants make during photosynthesis?What does your "carbon footprint" measure?Roughly how fast does light travel?What is the main advantage automakers expect from solid-state batteries?Quration — Quration Play