It was an ordinary day. Reading about...of all things...the science of spinning tops! For some reason I opened my Mac and there on the screen was a link to spinning tops which featured close to 100 different spinning tops. I have no idea why or how it found my desk-top, but I thought there must have been a reason...and that reason was so I could share the story with you! The spinning top is a toy unlike any other, having been played in some of the world's oldest cultures yet still beloved by people and collectors today. Historians aren't sure exactly when or where the original spinning top came to be, but they suspect that small, top-heavy objects found in nature, such as acorns, were the first to be spun for play. But, why have these toys fascinated both children and adults alike for thousands of years...myself included? The answer is, of course, is in the spin! Compared to modern toys, spinning tops may seem simple, but the physics behind them is anything but rudimentary. Tops have quite literally defied gravity since long before Newton coined the term, and for those of you interested in just how they are able to do so and what it is that makes them topple. Seems that when you spin a top into motion you are applying a force that causes the top's potential energy to turn into kinetic energy. As the top spins, it turns on an invisible vertical axis. According to Newton's third law of motion, also known as the law of the conservation of angular momentum, the top would continue to rotate on this axis/stay in motion as long as no external force acted upon it. But, as we know, no top can spin forever on its own--at least not on earth--because even the most perfect of tops are not perfectly balanced, nor are the surfaces on which they spin. Even though the amount of friction between the toy and the surface below is minimized by the top's tiny bottom, the force of friction becomes too much for the top, and its spin starts to slow. As this "other force" of friction acts upon the top, along with gravity, momentum is lost, and the toy begins to wobble. This wobbling, known as the scientific precession, tilts the top's axis to the side, allowing gravity to exert torque, another force, on the top as well. In response to the torque, the top spins a bit more and precesses outwards. This wobbling only gets faster as the top's spin gradually slows, an attempt to conserve the top's overall angular momentum. Soon, the top finally falls over, coming to a stop. So, maybe spinning tops aren't so simple after all! Making a top that spins at-length requires precision, artistry, and a keen awareness of the science that makes the world go 'round....pun intended! Interested in testing the physics for yourself or owning a top of your own? Check out some of the photos I have posted with this story. I'm sure a toy store somewhere can help you find that special top that will give you hours of fun, no matter how old...or young you may be. Hey...I have to stop typing now so I can go try my latest top! They really are fun...so they are! And...in case you were the one who sent me the information of tops...Thanks! It was another extraordinary day in the life of an ordinary guy. PS - the following are a variety of types of tops for your entertainment.
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