What was the greatest invention of the industrial revolution? Hans Rosling makes the case for the washing machine. With newly designed graphics from Gapminder, Rosling shows us the magic that pops up when economic growth and electricity turn a boring wash day into an intellectual day of reading.

Rectangular hyperbola A rectangular hyperbola, equilateral hyperbola, or right hyperbola is a hyperbola for which the asymptotes are perpendicular.

I mean, your grandparents had these great big cones, and then your parents had these odd boxes that would squawk at odd times during dinner, and now we have these little buds that nobody sees.

It's almost as if somebody came into your home and rewired your walls so that the next time you turned on the light switch, the toilet flushed three doors down, or your dishwasher went on, or your computer monitor turned off.

Given that the Book of Ingenious Devices was widely circulated across the Muslim world, some of its ideas may have also reached Europe through Islamic Spain, such as the use of automatic controls in later European machines or the use of conical valves in the work of Leonardo da Vinci.

The normal three kinds of light sensitive photoreceptor cells in the human eye (cone cells) respond most to yellow (long wavelength or L), green (medium or M), and violet (short or S) light (peak wavelengths near 570 nm, 540 nm and 440 nm, respectively).

We've seen the creation of small computers in the '70s and early '80s, and who would have thought back then that every single person would not have just one computer but probably 20, in your home, and in not just your P.C. but in every device in your washing machine, your cell phone.