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Submission + - 500-Year-Old Leonardo Da Vinci Sketches Show Him Grappling With Gravity (gizmodo.com)

Submitted by Anonymous Coward
An anonymous reader writes: A team of engineers studying the 500-year-old, backward writings of Leonardo da Vinci have found evidence that the Italian polymath was working out gravity a century before its foundations were established by Galileo Galilei. The team’s findings come from a revisit of the Codex Arundel, a compilation of documents written by da Vinci that detail various experiments and personal notes taken down in the latter 40 years of his life. The codex is freely accessible online courtesy of the British Museum. The team’s research is published in the MIT Press journal Leonardo.

Mory Gharib, an engineer at Caltech, said he stumbled across the writings in 2017 when looking for some of da Vinci’s work on flow in hearts. Though the codex was written over a long span of da Vinci’s later years, Gharib suspects the gravitational musings were written sometime in the last 15-or-so years of his life. Gharib recruited co-author Flavio Noca, a researcher at the University of Applied Sciences and Arts Western Switzerland, to translate the Italian’s backward writing on the subject. Da Vinci understood some fundamentals of objects in motion. He wanted to make an experiment testing how the motion of a cloud would correspond to the hail it produced, if the cloud’s velocity and any changes to it corresponded with the falling hail’s velocity. In lieu of control of the weather, da Vinci substituted a pitcher for the cloud and sand or water for the hail. Reliable clocks weren’t available until about 140 years after da Vinci’s death in 1519, the researchers note, so the inventor was forced to substitute the constant of time with space: by assuming that the time it took each water/sand particle to fall from the pitcher was constant, he just kept the pitcher at the same height throughout the tests.

Da Vinci’s sketch shows the positions of the falling material over the course of its trajectory toward the ground. By drawing a line through the position of the material at each instance in time, da Vinci realized that a triangle could be formed, with the drawn line being the hypotenuse. By changing the acceleration of the pitcher over the course of the experiment, one would change the shape of the triangle. Leonardo knew that the falling material would accelerate and that the acceleration is downward. What he wasn’t wholly certain on—hence the experiment—was the relationship between the falling material’s acceleration and the pitcher’s acceleration. In one particular case, when the pitcher’s motion was accelerated to the same rate as the falling material being affected by gravity, an equilateral triangle was formed. Literally, as Da Vinci noted, an “Equatione di Moti” or an “equalization of motions.” The researchers modeled da Vinci’s experiment and found that the polymath was wrong in his understanding of the relationship between the falling object and time. “What we saw is that Leonardo wrestled with this, but he modeled it as the falling object’s distance was proportional to 2 to the t power [with t representing time] instead proportional to t squared,” said Chris Roh, a researcher at Cornell University and a co-author of the researcher, in a Caltech release. “It’s wrong, but we later found out that he used this sort of wrong equation in the correct way.” The team interpreted tick marks on da Vinci’s sketches as data points the polymath made based on his eyeballing of the experiment in action. In lieu of a timepiece, da Vinci found the gravitational constant to nearly 98% accuracy.

Submission + - English May Have Retained Words From an Ice Age Language (sciencemag.org)

Submitted by sciencehabit
sciencehabit writes: If you've ever cringed when your parents said "groovy," you'll know that spoken language can have a brief shelf life. But frequently used words can persist for generations, even millennia, and similar sounds and meanings often turn up in very different languages. Now, a new statistical approach suggests that peoples from Alaska to Europe may share a linguistic forebear dating as far back as the end of the Ice Age, about 15,000 years ago. Indeed, some of the words we use today may not be so different than those spoken around campfires and receeding glaciers.

Comment Good. (Score 0) 1591

by jamesoutlaw (#42602075) Attached to: New York Passes Landmark Gun Law

It's far too easy for mentally unstable people to purchase guns and ammunition. Negligent gun-owners should also face harsher penalties when their weapons are used to commit crimes. I grew up with guns, and have no problem with responsible ownership. Unfortunately, there are far too many irresponsible gun owners in this country.

Comment Call them back, especially politicians (Score 2) 167

by jamesoutlaw (#40603979) Attached to: FTC To Revisit Robocall Menace

When I receive a political robocall, I make note of the politician who's the subject of the call and I then proceed to call their campaign headquarters and speak very rudely and sternly to the staff person who answers the call. I've gotten off several calling lists that way- lists that I NEVER asked to be on. It probably doesn't accomplish much, but I don't think it's a wasted effort to call and annoy people who willingly call and annoy me.

In local elections, I can frequently talk directly to the candidate. It's always fun to listen to them stammer and try to make an apology.

Note to politicians: If I want to hear from you, I will contact you. I don't need nor want you calling me and I don't need or want any of your "supporters" calling me on your behalf. I get enough of your foolishness in the media. I don't need to hear it over my phone.

Comment Re:Request a blood test (Score 1) 498

It looks like you misunderstood what I and several others have been trying to say. Being a responsible adult means either designating someone to be a designated driver or arranging some other way of getting yourself and your girl home after an evening of boozing it up. It's really not that difficult to do, but it does require a little effort and some forethought. If you can't do that, then you deserve to suffer whatever happens to come your way ... I just hope that you don't kill or injure anyone else when you decide to DUI/DWI.

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