Researchers turn to synchrotron imaging of historical and homemade prints to explore possible connections between early printing methods in Korea and Europe.

Observations of air-bubble mergers in water explain why dissolved salt slows this process and leads to foam.

Air bubbles churned up in pure water can easily merge. But bubbles merge far more slowly in seawater or in other liquids containing dissolved impurities, which is why such liquids often generate enduring foams. Now a team of engineers believes that it has identified the fundamental cause of the difference—subtle forces set up by electrolytes, mobile ions created when substances dissolve in liquids [1]. In a collision between two bubbles, these forces greatly reduce the rate at which the liquid separating the bubbles can flow away. This understanding, the researchers say, explains why foams arise so easily in salty seawater and could be useful in many industrial applications.

Solutions with high electrolyte concentrations often produce persisting foams, so researchers have suspected for decades that dissolved electrolytes somehow slow bubble mergers. The effect has remained mysterious, however, and many theories even suggest that electrolytes should speed up bubble mergers, says mechanical engineer Bo Liu of the University of Alberta in Canada.

An area known as Thacker Pass on the Nevada-Oregon border is home to clay that contain tens of millions of tons of lithium.

Alarmed by something popping up on your body that’s clearly not supposed to be there? These pictures from WebMD show you a few strange-bu t-true ailments that are scary looking but — for the most part — nothing to worry about.

The pain is invisible, but it’s there. Here are the stories of what it’s like to live with trigeminal neuralgia.

Newton thought that gravitation would happen instantly, propagating at infinite speeds. Einstein showed otherwise; gravity isn’t instant.