Ever wonder how much water is in a cloud? (Illustration by Yutaka Houlette)

How much water is in a cloud? What would be left if you squeezed the water out of it?

It depends on the cloud. A giant thunderhead may contain more than two billion pounds of water, but even a modest-sized cloud may contain water equivalent to the mass of a 747 jet. If you could squeeze the water out, the cloud would disappear. But you can’t. Some desert peoples use cloth “cloud catchers” to gather condensation and fill local water tanks for drinking and irrigation.

What is the practical use of the imaginary number √–-1? 

The number is “imaginary” in the mathematical sense (that is, its square is less than zero). Such numbers represent solutions to many algebraic equations, and they are central to describing the motion of waves in such practical areas as hydrodynamics and aerodynamics, electrical circuit design, quantum mechanics and the theory of heat conduction. Read more

It’s become an annual affair, the rafts of green algae washing up on the shores of Qingdao, China. Since 2007, massive algae blooms in the Yellow Sea have been fueled, scientists think, by “pollution and increased seaweed farming” south of Qingdao. The mats of photosynthetic phytoplankton aren’t dangerous to people (unless you count ruining a day at the beach as dangerous), but the return of these massive algae blooms year after year could be troubling for the marine creatures living in the Yellow Sea.

“The carpet on the surface can dramatically change the ecology of the environment beneath it,” says the Guardian. “It blocks sunlight from entering the ocean and sucks oxygen from the water suffocating marine life.”

Vast blooms of algae can cause the water to become “hypoxic,” to have the concentration of oxygen in the water drawn down so low that it makes it uninhabitable for many marine creatures. A strong case of hypoxia can further lead to something called a “dead zone.” And, by drawing down the oxygen levels and messing with the chemistry of the water, algae blooms can temporarily amplify ocean acidification.  Read more

Not long after NASA’s Cassini orbiter first reached Saturn in mid-2004, it found something spectacular. This was our first good look at the ringed giant since the Voyager mission in the 1980s. And Cassini saw that one of Saturn’s moons, Enceladus, was venting something into space.

Research went on to show that Enceladus’ mighty plumes, which can shoot up to 50 miles high, were mostly water—like a giant Old Faithful, pumping into space. The plumes were not only water, though, says science writer Matthew Francis. They contain other intriguing chemicals, like methane, carbon dioxide, nitrogen and other more complex carbon molecules. “While hydrocarbons are pollutants on Earth (which create that lovely yellow smog over our cities), they also are naturally-occurring compounds that may have played a role in the early biochemistry of life on Earth,” Francis writes. Read more

For decades, the pipes that brought water to LeAnne Walters’ house did their job unnoticed and safely. But in summer 2014, that changed.

Three People Hit With Criminal Charges Over Flint Water Crisis
Suddenly, Walters found that the water spewing out of her faucets was discolored and foul-tasting; her son would come out of the bath with alarming rashes. After meticulously sampling her house’s water and testing it with at-home testing kits, Walters discovered that it had lead levels far higher than those considered safe. The chemistry of the water flowing through her pipes had changed profoundly—with toxic results. Read more

A new crop of health wearables aims to keep users hydrated.

You don’t actually need to drink eight glasses of water a day. But, dehydration can have serious consequences—from kidney failure to brain swelling.

Hydration is the new frontier in the health tracker world. Researchers and young innovators are exploring a range of different approaches to tracking hydration—from sensor-packed patches to smart water bottles—hoping theirs will be the one that prevails as we head into a future of hotter summers and longer heat waves. Read more