Become a fan of Slashdot on Facebook


Forgot your password?
Slashdot Deals: Deal of the Day - Pay What You Want for the Learn to Code Bundle, includes AngularJS, Python, HTML5, Ruby, and more. ×

Submission + - Obama's Justice Department seeks expansion of surveillance (

ericjones12398 writes: "The Obama administration was elected on a promise of "hope and change." One area where the Obama administration has not differed much from its predecessor is on the subject of surveillance. Lawyers for the administration argued Tuesday that the American public has no expectation of privacy when it comes to mobile-phone location data."

Submission + - How to boil water without bubbles (

ananyo writes: "One trick to test whether a frying pan is hot enough is to sprinkle water on it. If the surface is sufficiently above the boiling point of water, droplets will skip across the pan. Those jittery beads of water are held up from the hot pan by a cushion of steam. The vapour cushion collapses as the surface falls below the 'Leidenfrost temperature', causing furious bubbling and spitting when the water droplet hits the surface and boils explosively.
The Leidenfrost effect lies behind the discovery, published today, that water can be made to boil without any bubbling if a surface is specially treated so that the vapour cushion does not break down. The key is to make the surface very water-repellent (abstract). The effect might be used to carefully control how metals are cooled and heated, or to reduce drag on ships. There's a video in the source showing the effect."

"Free markets select for winning solutions." -- Eric S. Raymond