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Electronics & Computers

How does a quartz watch keep time? A quartz watch counts the vibrations of a tiny quartz tuning fork that rings 32,768 times a second. A chip halves that 15 times to get exactly one pulse per second, which steps the seconds hand. How does GPS know where you are? GPS satellites keep sending the time. Your phone measures how long each signal took to arrive, turns that into a distance, and finds the one spot that fits all the distances. A fourth satellite fixes the phone's own clock, and the satellites' clocks are so exact that even Einstein's effect on time has to be corrected. How does a computer count? A computer is full of tiny switches that are either off or on, so it writes every number with just 0 and 1. Each switch is worth double the one to its right: 1, 2, 4, 8. Add up the ones that are on and you have the number.