A new atomic clock is one of the world’s best timekeepers, researchers say — and after years of development, the “fountain”-style clock is now in use helping keep official U.S. time. Known as NIST-F4, ...

In a grandfather clock, a pendulum swings back and forth and this periodic motion is maintained using the energy stored in its suspended weights. This is done with the help of the escapement mechanism ...

While some of us can fall asleep anywhere from a noisy auditorium to a brightly lit train station, others are more fussy, requiring quiet and dark to nod off. [Craig Lindley] likes to minimize light ...