Chemistry

When Nazi Germany occupied Denmark in 1940, chemist George de Hevesy dissolved two colleagues' Nobel Prize gold medals in aqua regia and left the yellow liquid on a shelf. The Nazis never noticed it. After the war, Hevesy recovered the gold and the Academy recast the medals.

The West long capped the basic tastes at four. In 1908 chemist Kikunae Ikeda isolated glutamate — the fifth taste, 'umami' — from kelp broth. The 'four tastes' dogma held nearly a century; umami became basic only after its tongue receptors were found in 2000.

One of the first mass-produced purple synthetic dyes came from a failed malaria-drug chemistry experiment. In 1856, 18-year-old William Perkin tried to synthesize Quinine and found a dye for silk.

The Statue of Liberty wasn't always green — it began shiny brown. Its skin is copper, so in 1886 it gleamed a coppery hue. Sea air, salt and pollution oxidized it into a blue-green patina, complete by about 1920. The patina isn't damage; it shields the metal.

Seasonings slow food spoilage not by killing microorganisms, but by stealing their water. Salt and spice molecules bind with free water in food, lowering its 'water activity.' Even if water is present, microbes cannot use it.

Pufferfish venom blocks sodium channels in nerves, while monkshood venom activates them. Because the two poisons work in opposite ways, taking them together delays their effects. In 1986, a murderer in Japan exploited this principle to delay the time of death and fabricate an alibi.

Pure water is an insulator. Electricity passes through water not because of the water itself, but because of dissolved ions. Tap water conducts electricity well because it contains ions like chlorine from disinfection.