Amateur Time Hackers Play With Atomic Clocks at Home So he loaded the family's blue minivan with portable power supplies, monitoring equipment, and three HP 5071 cesium clocks. With his three kids and some camping gear in tow, he drove the winding roads spiraling up Washington's Mt. Rainier and checked the family into a lodge 5,319 feet above sea level. They hiked the trails, and the kids relaxed with board games and books, while in the imperceptibly lessened gravity, time moved a little bit faster than at home. When the family returned to the suburbs two days later, the cesium clocks were off by the precise amount relativity predicted. He and his family had lived just a little more life than the neighbors. "It was the best extra 22 nanoseconds I've ever spent with the kids," Van Baak says.