President Obama visits a battery-research lab in suburban Chicago to announce a $2 billion plan to boost battery and transportation research. Scientists at the lab are in pursuit of a battery that could have a profound effect on how we power our gadgets, cars, and homes.
March 14 is Pi Day, which celebrates the mathematical constant measuring the ratio of a circle's circumference to its diameter (beginning with 3.14). Pi Day is celebrated internationally, and in 2009 it was decreed an official holiday by the US House of Representatives. Here are 3.14 ways to celebrate.