A closer look
The foundational law of how gases behave was discovered by scientists casually pouring gallons of deadly neurotoxins into a giant glass straw. To prove that the pressure and volume of a gas have an inverse relationship (Boyle's Law), Robert Boyle and Edme Mariotte needed to squeeze air in a measurable way. They didn't have high-tech compressors in the 1600s, so they built a massive J-shaped glass tube, trapped a bubble of air in the short end, and just started dumping liquid mercury down the long end. As the heavy mercury piled up, its immense weight compressed the trapped air. By measuring the height of the mercury against the volume of the air bubble, they unlocked modern thermodynamics—while happily marinating in lethal mercury vapors.
