![]() If you move a pendulum just a little bit away from its equilibrium position, the force of gravity is what pulls it back towards the equilibrium position. Here on Earth, the gravitational force is what drives the swinging of a pendulum. longer pendulums take longer to complete one oscillation, and the acceleration due to gravity, where larger amounts of gravity results in faster pendulum swings. In general, there are only two factors that determine the period of a pendulum: its length, where. The reason would have been totally obscure to anyone living in the time of Galileo, but it began to make sense once we started to understand how gravitation worked. The clock - which kept exquisitely accurate time in Europe - would have begun running at the wrong rate in the Americas once again. If they had send that clock back to the Americas from Europe, they would have seen exactly the same phenomena occur. ![]() ![]() Yet, as soon as you drive away, it inevitably starts having that problem again. The omnipresent problem that you’ve been experiencing constantly suddenly resolves itself when you arrive at the one person who could diagnose and fix it. You notice the problem, you take it to a mechanic, and as soon as you arrive at the mechanic, the car starts behaving as though nothing is wrong. This maddening experience is familiar to anyone who’s ever been in a scenario where your car is doing something you know it shouldn’t be doing: making a funny sound, handling improperly, getting too hot, etc. The fact that the same pendulum swung at different rates in different locations was a hint towards Newton's gravitation. changes, and large angle effects can be neglected, will always have the same period when subject to the same gravitational acceleration. To within 2 seconds per day, the clock was perfectly accurate.Ī pendulum, so long as the weight is all in the bob at the bottom while air resistance, temperature. When it arrived, they wound the clock, observed its ticking, and compared it to all the other ways they knew of to keep time: to other clocks, to sundials, and to the rising and setting of celestial objects. After another trans-Atlantic journey, where the clock was returned from the Americas to the Netherlands. So they did the only thing they knew how to do: they send the clock back to the manufacturer for repair. By the end of the first week, it was off by nearly 5 minutes.Ĭlearly, they concluded, the clock must have suffered some damage during the trans-Atlantic journey that was required to transport the clock from Europe to the Americas. Whereas the clock was supposed to be accurate - at the time - to within about 2 seconds per day, or about 15 seconds per week, it was running slow by more than 30 seconds per day. Moreover, the mismatch was getting worse with each passing day. Within a single week, people noticed that the Sun and Moon weren’t rising or setting at the predicted times, according to this new clock. While this fact was generally appreciated back then, it wasn't appreciated that the gravitational acceleration, and hence the period of a pendulum, would also be different. higher latitudes (closer to the pole) to lower, more equatorial latitudes. But once that clock arrived in America, was wound, and began ticking, everything began to go wrong.Ī journey from Europe to the Americas, in the 1600s, would have typically meant traveling from. Sunset/sunrise and moonset/moonrise times were accurate for weeks, with stars rising and setting within a minute of the predicted time without any calibration for approximately a full month. The clock, built and calibrated in the Netherlands, was exquisitely accurate. Which is why it was such a puzzle when the first pendulum clock was brought from Europe to America. The first American-built clock wouldn’t occur for many decades after that advance, and so the first American timekeeping devices were imported. By developing a temperature-compensated pendulum - where the period of a swing didn’t change even as the temperature did - pendulum clocks could be accurate to within just a few seconds per week. ![]() The major known “source of error” that occurred with these pendulum clocks was due to temperature changes: the length of the pendulum would increase or decrease as the materials they were made out of expanded or contracted with temperature. Christian Huygens, 1658Īll of these innovations had been made prior to 1700: a remarkable set of advances in a short amount of time. Many subsequent refinements, even prior to Newton's gravity, were made to this original design. The drawings come from Huygens' 1658 treatise, Horologium. which was designed by Christiaan Huygens and built by Saloman Coster. The front view (L) and side/schematic view (R) of the first pendulum clock ever built, in 1656/7. ![]()
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