When Brazilian defender Roberto Carlos struck a powerful free-kick from about 30 meters out in a 1997 international match against France, he could not have known that scientists would still be discussing his feat more than a dozen years later. Indeed, he could not even have known that the ball would improbably find the back of the net . But find the net it did, swinging well wide of a wall of French defenders, hooking viciously to the left, and glancing off the inside of the goalpost. The French goalkeeper could only turn and watch in apparent disbelief as the ball came to rest in his goal. [More]



Roberto Carlos - Physics - France - Association football - Goalkeeper

Sonic booms can occur in fairly routine settings: for example, it is a sonic boom you hear when a whip cracks. But in your bathtub? Apparently, whenever a hard object falls into a pool of water, a jet of air is produced that briefly reaches supersonic speeds .

To study this, physicists at the University of Twente, in the Netherlands, and at the University of Seville set up an experiment in which they plunged a disc-shaped object flat down into water at the relatively leisurely speed of one meter per second. 

Sonic booms can occur in fairly routine settings: for example, it is a sonic boom you hear when a whip cracks. But in your bathtub? Apparently, whenever a hard object falls into a pool of water, a jet of air is produced that briefly reaches supersonic speeds .

To study this, physicists at the University of Twente, in the Netherlands, and at the University of Seville set up an experiment in which they plunged a disc-shaped object flat down into water at the relatively leisurely speed of one meter per second. 

Sonic booms can occur in fairly routine settings: for example, it is a sonic boom you hear when a whip cracks. But in your bathtub? Apparently, whenever a hard object falls into a pool of water, a jet of air is produced that briefly reaches supersonic speeds .

To study this, physicists at the University of Twente, in the Netherlands, and at the University of Seville set up an experiment in which they plunged a disc-shaped object flat down into water at the relatively leisurely speed of one meter per second. 

Here's one you can try at home: Fill a dish with water and drop a small amount of flour onto the surface. The flour particles disperse rapidly, like a tiny starburst, and spread out over the liquid surface. [More]

Editor's note: The original online version of this story was previously posted.

Magnets are remarkable exemplars of fairness--every north pole is invariably accompanied by a counterbalancing south pole. Split a magnet in two, and the result is a pair of magnets, each with its own north and south. For decades researchers have sought the exception--namely, the monopole, magnetism’s answer to the electron, which carries electric charge. It would be a free-floating carrier of either magnetic north or magnetic south--a yin unbound from its yang.