To test the presence of 'Alternating current' (AC), electric line tester is used. In AC, phase line gives both

How refrigerator works?We all know when a mud pot in summer covered by a wet cloth around it, the water in the pot become cool.

The color black usually signals the absence of light. But inside the solar system, space is filled with light.

In space, rockets zoom around with no air to push against. What's going on?
Rockets and engines in space behave according to Isaac Newton's third law of motion: Every action produces an equal and opposite reaction.

Pupils turned red so often ruin otherwise great photos. And though many photo editing programs offer a digital fix for the "red-eye effect," correction after the fact never looks quite right. Fortunately, there are ways to keep pupils looking black from the start.

When you and I calculate two plus two, we imagine a number line, start at two and hop over a couple of spots to get to four (or at least we did until we memorized the answer). Simple — so simple, in fact, that "putting two and two together" is an analogy for deducing something obvious.

With the summer upon us, cooling off is becoming more and more important. While everyone enjoys the benefits of air conditioning, for many people, how the air is actually cooled is one of life's little mysteries.

google gravity:
http://mrdoob.com/projects/chromeexperiments/google-gravity/

google tilt:
http://www.google.co.in/#hl=en&output=search&sclient=psy-ab&q=tilt&fp=1&bav=on.2,or.r_gc.r_pw.r_qf.&cad=b

The popularity of smart phones is growing at a breakneck speed, raising concerns over cell phone viruses.
Cell phone viruses first broke onto the scene in 2005 when hackers learned how to utilize Nokia's Symbian Series 60 phone's text messaging system.

Though they're not a living thing like you and me, computers can get "sick" from viruses, too.
A computer virus is a software program designed to replicate itself and spread to other machines. In most cases, the program is "malicious," meaning its purpose is to cause the computer malfunction in some way.

The arrangement of the first six letters in the top alphabet row of a standard keyboard – QWERTY – goes way back. The layout was created in 1873 when Christopher Latham Sholes made improvements to his earlier typewriter models in order to design a quicker and more efficient typewriter for E. Remington and Sons.
Sholes noticed the alphabetical layout of the keys in his original models tended to jam, so he changed their order, spreading the most common pairs of letters farther apart. Sholes' QWERTY model was named the Remington and became available as the first commercial typewriter in 1874. Since then, many alternatives to QWERTY have been created, such as the Dvorak Simplified Keyboard (named after professor and co-creator August Dvorak) and the Colemak keyboard layout. Even though these new keyboards are designed to increase typing speed while maintaining ergonomic considerations, QWERTY remains the standard.
"The QWERTY keyboard layout was developed to reduce keys jamming on mechanical typewriters to improve typist productivity," Alan Hedge, a professor in the Department of Design and Environmental Analysis at Cornell University, where he directs the Human Factors and Ergonomics research programs.

"These days computers don't have keys that jam, but even though QWERTY isn't the optimal keyboard layout, it's not the worst and it seems that we're stuck with it," Hedge told Life's Little Mysteries.
As in other behaviors, it seems, humans are creatures of habit:
"With electronic keyboards, there is no need for QWERTY, but people have become accustomed to the design and that is why it continues to be used," explained Robert L. Goldberg, a professor at the University of California's Ergonomics Program.

Aryabhata (476 BC)