But probably the most brilliant thing about Leo  was his ability to both observe and really meticulously record — in words and in beautiful illustrations — the natural world. These two skills combined in one of his greatest scientific passions, his study of flight. He observed all kinds of different birds, analyzing their muscles and how their feathers functioned. He did dissect them and record what he saw, but he also was known to just buy caged birds and let them loose.

Then he began to think, ‘If a bird can fly, then maybe a human can, too.’ This was a possibility that held particular fascination for Leonardo. He captured all of his designs and observations in notebooks which he often organized by subject in volumes known as codices. In the early 1500s, he put together one all about flight called the ‘Codex on the Flight of Birds’. It’s over 35,000 words and contains 500 sketches relating to bird flight, gravitational theory, balance, wing design, the properties of air, and his famous flying machine ideas.

He invented the first parachute and designed a flying machine known as the ornithopter, a contraption with manually powered wings that, while kind of dangerous, impractical and totally zany-looking, would later prove to actually work.  He was the first to ponder the concept of the force of lift, which enables objects to fly.  Like many great scientists, he was wrong a lot. Like, at first he believed that high-pressure, high-density air formed under a wing in flight and that exerted an upward force.  BUT years later, after more observation and experimentation, he correctly concluded that lift is created because the pressure on the top of the wing as air flows over it is less than the pressure underneath it.

This, of course, all hundreds of years before the world would see any kind of progress toward an actual flying machine; but Leo planted a seed of possibility and many of his inkling concepts having to do with aerodynamics, wing design, and gravity would be re-visited in the early twentieth century's airplane engineering boom.

As an architect and engineer, Leo also flexed his inventor's imagination and proposed building a 240-meter bridge across the Gulf of Istanbul. Unfortunately as with many of his other innovative ideas, other career engineers at the time shot the project down, saying he was out of his gourd to think a bridge that big could work. BUT in 2001, a Norwegian artist built a smaller scale version of Leo's bridge and found that it held just fine. Now plans are in the works to construct the real thing back in Istanbul. Take that, haterz!

Leo was also intrigued by all forms of water, be they ice, liquid, or steam. He drew up plans for different kinds of waterwheels, a steam powered cannon, a humidity measuring device, and various machines that could run off the power of flowing water. He also drafted early designs for underwater breathing devices like the iconic diving hood and mask, and different diving bell designs, as well as the first life preservers and dredges for digging harbors.

Leonardo might have been the greatest inventor the world has ever or will ever know, but virtually all of his inventions were either too complicated for the technology of the time or too expensive to attempt without a wealthy patron. All this flitting around to different disciplines frustrated some of his artist cronies, who saw him as a brilliant but flighty procrastinator, too easily distracted by his scientific interests when he should've been out there cranking out more masterpiece paintings. But none of Leo's pursuits combined his passion for both art and science better than his pioneering study of anatomy —perhaps his greatest scientific contribution.

He dissected over thirty human corpses —much to the chagrin of the Church —and his wonder and admiration for the human body is obvious in his drawings and detailed notes. He sketched lavishly detailed renderings of muscles, tendons, nerves, bones, skulls, and hearts. Every sweep of muscle, cage of bone, or tangle of vein is a revelatory masterpiece. 

And he didn't just draw what he saw —he experimented. He pulled and prodded, tugged at muscles to see what happened. He injected organs with wax to make plaster casts of them and observed their structure to see how they work together. He was figuring out staff no one knew at the time —for example, suggesting that arteries clog over time, creating a health risk.

In his last major dissection campaign Leonardo tackled the heart, creating a specific Codex about it. In one study he injected an ox heart with molten wax, cast a glass model from the wax mold, and pumped it full of liquid to observe how the valves opened and closed. What he learned about the function of these valves was revelatory and fundamental to the way the heart works. But of course because his research was never published it wasn't until the twentieth century that cardiologists got around to figuring this out and when they did, they confirmed that Leo was absolutely right about the shape and function of these valves. In fact his detailed accounts of the mitral valve --which connects the left atrium of the heart with the left ventricle --have recently been re-analyzed by modern cardiologists, inspiring ideas on how to restore the natural opening and closing of damaged valves.

Even with today's technology, physicians are still learning from da Vinci's five-hundred-year-old observations!

Leo intended to publish his anatomical studies but for reasons we're still not sure of, this never happened during his lifetime. Instead, his collection of drawings was kept private for decades until a bound volume of some six hundred of his sketches mysteriously appeared in Britain in the late 1600s. Many believe that if his anatomical collections had been published in his lifetime, Leonardo would have been hailed as one of the key founders of anatomy, instead of only a footnote.

Like many of the Great Minds we've learned about here on SciShow, Leonardo was an interdisciplinary genius whose contributions to science weren't recognized until long after his death. But there is a lot that we can still learn from him. The integration of disciplines; the power of observation and recording; the recognition that Nature can be inherently beautiful and operates as an interdependent web that connects all systems and all living things -- Leonardo was a genius because he knew this stuff five hundred years ago and some of us are still learning it.

Thanks for watching. This SciShow Infusion was filmed with support from Audible.com, a leading provider of digital spoken audio information and entertainment on the internet -- kinda like SciShow, but without the pictures. Audible.com has over 150,000 titles including books on anatomy, flying, and da Vinci himself. If you'd like to go try Audible.com for yourself, go to Audible dot com slash SciShow to download a free audiobook.

[=SciShow theme and credits]