Although we take a lot of scientific knowledge for granted today, each of the basics – whether it be about light, gravity, mass or the shape of the Earth – had to be theorized and experimentally verified. In the case of gravity, as far back as around 500 BCE the Ionian Greek philosopher Heraclitus theorized on the balance created by what we came to call ‘gravity’. Later, the Greek philosopher Aristotle coined his own postulations and Greek physicist Archimedes did research that led him to discover the center of mass. Centuries later, the Roman engineer and architect Vitruvius argued for the concept of specific gravity rather than mass alone.
Although scientific pursuits in this area ground to a halt in Europe during medieval times, the Renaissance saw a renewed interest in the topic, with newly published research performed on Leonardo da Vinci‘s notes showing that he appears to – unsurprisingly – have also created a number of experiments aimed at determining the properties of gravity. One of the major limitations of the 15th century was that many of the basic scientific tools we have come to rely on since the 19th century such as accurate clocks, along with many other products of advanced alloys and metallurgy simply did not exist. Da Vinci’s experiment in this context is nothing if not ingenious in its simplicity.
By the time of the European Renaissance, the Aristotelian concept of gravity as solely a factor of an object’s mass was dismissed by many in favor of a model that saw the motion of an object affected by its velocity and mass, also influenced by works published by Persian scholars. When Da Vinci set up his experiment, he focused specifically on the acceleration of the falling objects by pouring a large number of granules or possibly water droplets from a pitcher which was being pulled along a straight path. He theorized that if the pitcher was being accelerated at the same rate as the objects are accelerating due to gravity, it’d create a isosceles right triangle.
When the researchers ran his experiment and compared Da Vinci’s notes on the results, they realized that although he had made a mistake in his model, at the small scale this would not have affected the results, making it valid and an early precursor to what later be published by Isaac Newton in the 17th century.
It’s the season to be surrounded by greeting cards of all shapes and sizes from friends old and new. News of their families and achievements, reminders that they exist, and a pile of cards to deal with sometime in January. Wouldn’t it be great if you could send something with a little more substance, something your friends would remember, maybe even hang on to?
[Brian Brocken]’s 3D-printed Da Vinci catapult kit may not fill that niche for everyone, but we can guarantee it will be a talking point. The Da Vinci catapult design uses a pair of springs similar to an archer’s bow, to unwind a pair of ropes and thus turn the shaft upon which the catapult shaft itself is fitted. All these components are mounted in a single piece with sprues similar to an injection moulded model kit, allowing the whole to easily be posted in an envelope.
The parts are all available to print separately among the files on the Thingiverse page for those with no need to mail them. For the casual spectator he’s made a YouTube video that we’ve placed below the break, detailing the design and build process as well as showing the device in use.
Here’s a fun fact, the kind of thing that you might (but we definitely did not) find out when writing a blog post: Dan Brown actually made up the cryptex for his book, The Da Vinci Code. We therefore have Mr Brown, with a bit of help from the filmmakers over at Sony, to thank every time we see somebody make their own version. To follow that line of logic to its conclusion, we believe you’ll agree that the following is without question the greatest thing Dan Brown has ever done in his life.
Frankly, it’s hard to do justice to what [Stephen] has created in so short a space, and you really should browse through the 140+ images in his gallery. But the short version is that after some furious white board sketching, [Stephen] moved over to AutoCAD and then SolidWorks to design all the parts which would eventually get machined out of aluminum. As a very clever touch, he wisely added 17° slop in the locking mechanism so that the recipient wouldn’t fumble too much at the big moment.
When the machining was all said and done, [Stephen] then switched over to the woodworking part of the project. Rather than numbers or letters for a combination, this cryptex uses the grain pattern in the turned piece of wood. This gives the final product a more organic feel, while at the same time avoiding the head-scratching problem of getting the characters printed or engraved into the wheels.
Towards the end of construction there was a worrying moment when the newly made wooding rings warped so badly that the aluminum inserts would no longer fit. As a last resort, the rings were placed in a box with a humidifier for a week and slowly worked back into shape. [Stephen] says he’s still surprised it worked.
Leonardo Da Vinci had many unfinished projects, not unlike many hackers here. Lucky for us though, he was a bit better at writing down his ideas than we are. This is his Viola Organista, as recreated by [Slawomir Zubrzycki] — a mechanical work of art, that sounds good too!
If you’re familiar with a Hurdy gurdy, this is basically the same thing — but on a much bigger scale. It is the combination of an organ, a harp, and a viola. Instead of a hammer hitting the 61 steel-strings, spinning wheels of horse-hair (similar to a bow) caress each string via input from the keyboard and the pedal powered crankshaft. The result is a very unique sound, which is reminiscent to each of the instruments it combines.
The designs for the instrument were found in Da Vinci’s Codex Atlanticus, a 12-volume collection of many of his manuscripts and designs, documenting everything from his flying machines to weaponry. [Slawomir] spent three years and over 5000 hours perfecting his version of it.
Stick around after the break to hear it in action! Don’t forget to turn on the subtitles though, unless you’re fluent in Polish!