Understanding Greek and Roman Technology: From Catapult to the Pantheon [TTC Video]
31 August 2019, 22:14
Course No 1132 | MP4, AVC, 2000 kbps, 1280x720 | AAC, 192 kbps, 2 Ch | 24x30 mins | + PDF Guidebook | 11.08GB
Famed for great thinkers, poets, artists, and leaders, ancient Greece and Rome were also home to some of the most creative engineers who ever lived. Many of their feats have survived; others have disappeared into the mists of time. But modern research is shedding new light on these renowned wonders—impressive buildings, infrastructure systems, and machines that were profoundly important in their own day and have had a lasting impact on the development of civilization.
The glories of ancient Greek and Roman engineering include these iconic buildings:
- The Greek Parthenon: Arguably the most aesthetically pleasing structure ever built, the Parthenon achieves this effect through astonishing precision in its architectural plan and stone masonry construction.
- The Roman Colosseum: This ingeniously designed, mammoth arena represents a grand compromise between traditional stone masonry and a revolutionary construction method incorporating brick and concrete.
- The Roman Pantheon: The ancient world’s most ambitious engineering achievement, the Pantheon is known for its cast concrete dome that has never been equaled in beauty or construction ingenuity.
Also on the list of impressive achievements are ancient technologies that you use every day:
- Roads: Networks of well-drained, hard-surfaced roads are a legacy of the Romans, who even installed curbs, wide shoulders, and periodic steps to aid travelers in mounting horses or carriages.
- Water systems: Large-scale systems for supplying clean water and drains for carrying away wastewater were also developed by the Romans, whose aqueducts and sewers transformed urban life.
- Pumps: The Greeks and Romans invented a variety of techniques to move water. One, Archimedes’ screw, remains in widespread use today in devices from combine harvesters to snowblowers.
These and many other developments grew out of the same conditions that produced new political institutions, stunning sculptures, outstanding literary works, and empires that constituted much of the known world. In such a climate, is it any wonder that technology also flourished? Yet the engineering exploits of the Greeks and Romans are not as celebrated as they deserve to be, and they have been long discounted by some historians. However, new discoveries combined with a reevaluation of evidence show just how clever our ancient ancestors were.
In 24 lavishly illustrated lectures, Understanding Greek and Roman Technology: From Catapult to the Pantheon gives you an in-depth appreciation for what the Greeks and Romans achieved and how they did it. Your guide is Dr. Stephen Ressler, a former professor at the United States Military Academy at West Point, a civil engineer, and a nationally honored leader in engineering education.
A Golden Age of Engineering
Understanding Greek and Roman Technology is a fascinating introduction to basic engineering principles and the science behind them. The course also gives a new perspective on one of the most productive periods in the history of civilization: classical antiquity. In case after case, you will find that engineering solutions reached during this era would not be surpassed for another thousand years or more.
These lectures are also ideal preparation for anyone planning to visit Greek or Roman sites. Even ancient building rubble is captivating if you know what to look for: tool marks, holes for joining pegs, projections used for lifting, and other signs that tell the purpose of a particular block of stone. Professor Ressler describes a field trip to an archaeological site in Turkey, where one of his students noticed chiseled Greek letters on foundation stones—markers that were clearly used to place the stones in their correct positions.
Clue by clue, Professor Ressler assembles a detailed picture of how ancient engineers went about their work. First you learn about the building materials available in antiquity and their strengths and weakness under different loads. Then you proceed to the three major sections of the course, which cover structures, infrastructure, and machines. Here is a taste of what you will learn:
- Concrete: The versatility of form and composition of concrete made possible enormous structures and efficient new architectural forms in Rome’s awe-inspiring building program. Professor Ressler demonstrates the role of concrete in a sturdy Roman wall.
- Cranes: Trajan’s Column in Rome consists of marble drums weighing as much as 60 tons each. How were they lifted into place? Professor Ressler shows how cranes powered only by human muscles were up to the job.
- Catapults: Engineers improved catapults over a period of 700 years, developing new ways to store energy and propel a heavy projectile to its target. Innovations associated with this weapon include the universal joint, now used in automobiles.
- Triremes: Professor Ressler’s favorite piece of ancient technology is the trireme, the racehorse of Greek warships, with three banks of oars and a bronze ram. Details of its design and construction were long uncertain—until 20th-century enthusiasts decided to build one.
- Lead pipes: One of the many theories explaining the fall of Rome blames chronic lead poisoning from lead pipes used in water systems. But Professor Ressler explains why this idea does not “hold water.”
- Slaves: A widespread theory contends that the Greeks and Romans had no incentive to develop labor-saving machines because of their access to slaves. But Professor Ressler proves that many ancient projects would not have been possible without unprecedented technology.
Get inside the Classical Mind
An engineer in the mold of his versatile predecessors in antiquity, Professor Ressler not only created all of the physical models used in this course but most of the computer models as well. Unlike off-the-shelf graphics, these animations are tailor-made to answer specific questions in the lectures, deepening your understanding of how ancient engineers worked and giving you a realistic picture of ancient problem solving in action.
Understanding Greek and Roman Technology opens with a thought-provoking lesson. In 480 B.C., Greek naval forces decisively defeated the invading Persian armada at the Battle of Salamis, thanks to the Greeks’ superior deployment of technology. The Greeks maximized the performance of their trireme warships to overcome a Persian advantage of 3 to 1. Had they not achieved this crucial edge, they surely would have lost, halting the growth of classical civilization before it could spread. What better demonstration of the influence of technology on the course of human events!
Impossible: Physics beyond the Edge [TTC Video]
30 August 2019, 12:05
Course No 1299 | MP4, AVC, 2000 kbps, 1280x720 | AAC, 192 kbps, 2 Ch | 24x30 mins | + PDF Guidebook | 11.03GB
Physicists spend a lot of time thinking about impossible things, since probing the constantly shifting bounds between the possible and impossible is one of the best ways to discover unexpected phenomena and new laws of nature. And for nonscientists, exploring this extraordinary realm is one of the best introductions to the immensely rich subject of physics.
Consider these questions:
- Can machines produce limitless energy?
- Is time travel possible?
- Can anything travel faster than light?
- Is it possible to escape from a black hole?
Each is a puzzle that requires pieces from different parts of physics to solve. And after investigating these and other questions, you begin to see how all of physics is tied together in a system that is consistent, logical, beautiful, and often very surprising.
For example, the question about whether time travel is possible leads you to a study of the nature of time and space. The paradoxes you encounter there are directly related to Einstein's concepts of space-time and the constancy of the speed of light from his theory of relativity. This, in turn, takes you to exotic ideas such as black holes and wormholes, which some theorists believe may be potential shortcuts through space-time.
Before you know it, a staple subject of science fiction—time travel—has taken you through many layers of investigation to reveal profound truths about the universe.
Impossible: Physics beyond the Edge uses this ingenious approach in 24 delightful half-hour lectures that will entertain and nourish your mind, while teaching you more physics than you ever imagined. Your guide into the realms of the impossible is veteran Great Courses Professor Benjamin Schumacher of Kenyon College, a pioneering theorist in quantum information, which is a field dealing with things once deemed impossible.
Is It Possible?
Designed for those with no previous knowledge of physics, Impossible: Physics beyond the Edge will also appeal to the spirit of whimsy and adventure in those already well grounded in the subject. The course is illustrated with hundreds of diagrams, 3-D animations, and images to convey fundamental ideas at the core of physics—all in pursuit of the answer to the question, "Is it possible?"
Thanks to today's science-fiction-rich media, people are more inclined than ever to think that the fanciful is real, that imaginary creations such as perpetual motion machines and warp-drive space engines are feasible technologies. Impossible: Physics beyond the Edge serves as an enlightening corrective to this outlook.
On the other hand, modern physics is full of real phenomena that are so counterintuitive that they seem like science fiction. Here are a few that you encounter in this course:
- Near-absolute zero: Reaching the coldest possible temperature—absolute zero at -273.15º C—is probably impossible. But as some substances approach this limit, electrical resistance and viscosity drop to zero, and a strange new form of matter emerges.
- Time dilation: According to Einstein's special theory of relativity, a clock in motion keeps time more slowly than one at rest—from the point of view of an observer at rest. However, an observer accompanying the moving clock notices no time slowdown at all.
- Quantum tunneling: In the quantum world, particles can do the equivalent of walking through walls—appearing on the other side of an apparently impassable energy barrier. The effect has many uses, including the scanning tunneling microscope, which can "see" atoms.
- Entanglement: In the strangest of all quantum effects, a pair of particles acts together as a system; if something happens to one particle, the other responds instantly, even if it is millions of miles away. It seems like a violation of faster-than-light communication, but it isn't.
From Thermodynamics to Information Theory
Professor Schumacher begins the course by investigating three ways that scientists interpret the impossible and how these approaches inspired important breakthroughs by Euclid, Isaac Newton, and James Clerk Maxwell. Historically, some inventions and discoveries were called impossible shortly before they were actually achieved, and you learn how there is a danger of being like the eminent scientist Simon Newcomb, who in 1903 declared that humans would never fly, just a few weeks before the Wright brothers took off over Kitty Hawk.
The opposite risk is chasing a dream that the laws of physics won't allow. The most notorious example is a device that produces limitless energy—a perpetual motion machine. Professor Schumacher's discussion of this long and fruitless quest leads you to one of the most important sets of ideas in physics: the three laws of thermodynamics, which were developed in the 19th century in concert with the technological innovations of the industrial revolution.
From here, you survey the advancing frontier of physics, as startling new theories changed our perception of what's possible and what's not, including such revolutions as these:
- Relativity and quantum theory: Starting in the early 20th century, these two groundbreaking theories have done more than anything else to remap the border between the possible and impossible.
- Chaos theory: The discovery that the future is hostage to unpredictable, chaotic fluctuations in present conditions destroyed the dream that the future can ever be forecast with any certainty or precision.
- Noether's theorem: In the early 20th century, mathematician Emmy Noether made the remarkable discovery that the great laws of physics, such as the conservation of energy, result from symmetrical features of space and time.
- Information theory: Information is a powerful idea in physics and at the heart of many impossible phenomena, such as the impossibility of anything traveling faster than light—in which "anything" means "information."
You will also see how the square-cube law in mathematics was used as long ago as the 17th century to conclusively dismiss an idea that still won't die: that gigantic insects and other larger-than-life creatures are plausible life forms.
Impossibility as a Tool of Understanding
By the end of the course, you will have probed the nature of the impossible from many points of view and in many branches of physics—discovering that racing a light beam, hovering over a black hole, chasing quantum particles, trying to reverse the flow of time, and other astounding adventures make an excellent education in the fundamental laws of nature. These laws work together to create the sometimes perplexing, frequently surprising, and always wonderful world in which we live. As Professor Schumacher says, "If our goal is understanding, then there is nothing more practical than the impossible."
Outdoor Fundamentals: Everything You Need to Know to Stay Safe [TTC Video]
29 August 2019, 15:34
Course No 9702 | MP4, AVC, 1372 kbps, 960x540 | AAC, 128 kbps, 2 Ch | 24x27 mins | + PDF Guidebook | 7.32GB
There’s nothing like a trip to the great outdoors. As any avid camper, hiker, backpacker, or paddler knows, stepping out of the civilized “front country” for a few hours, days, or even weeks offers physical, mental, and spiritual regeneration unlike any other experience. But if you’re not already an outdoors enthusiast, where would you even start as an outdoor adventure? Why should you even start? Isn’t the outdoors an experience of “roughing it” with bugs, bears, and bad weather?
Not at all! While it’s true that a trip onto open water or into the wilderness does come with a variety of challenges—and dangers—outdoor adventures truly are accessible to everyone. With the right gear and a little bit of know-how, a journey into the great outdoors can be a truly wonderful experience.
As the great outdoorsman Nessmuk (pen name of George Sears) once wrote, “We do not go to the green woods and crystal waters to rough it, we go to smooth it. We get it rough enough at home; in towns and cities.” Outdoor Fundamentals: Everything You Need to Know to Stay Safe is all about transforming the idea of roughing it in the wild to “smoothing it” and having the best experience possible. Taught by Professor Elizabeth K. Andre, a highly experienced and accredited wilderness guide and a professor at Northland College, these 24 insightful lectures will give you the practical skills, knowledge, and insight you need to set off for the water or the woods.
Whether you pride yourself on your outdoor prowess or consider yourself an avid indoorsperson, you will find a wealth of practical tips and tricks for enjoying the outdoors, including:
- What gear you need to pack (and what you can leave at home);
- Setting up camp and building a fire;
- Staying hydrated on the trail;
- Decision-making and risk assessment;
- Navigation basics;
- Hygiene and cleanliness; and
- Wilderness first aid.
Most importantly, Outdoor Fundamentals: Everything You Need to Know to Stay Safe is about enjoying your next (or your very first) trip to the backcountry! From hiking the woods of Maine, to sea-kayaking the waves of Lake Superior, to exploring the wild country of Big Bend National Forest, Professor Andre has an incredible amount of experience as an expedition guide, and she fills this course with stories of adventure, harrowing tales of survival, and real-world lectures to help familiarize you with what it’s like to spend a day on the river or a night in the woods.
Discover the Basics of Outdoor Adventures
If you’ve never been camping before, this course will clue you in on what you’ve been missing, and will get you ready to tackle everything from a weekend of car camping to multiple weeks in the bush. But even frequent backpackers or paddlers will learn something new among Professor Andre’s many practical lectures. Among other topics, you will study:
Gear and Clothing: How much do you need? Is the top-of-the-line stuff worth the price? What’s the best way to stay warm and dry? From camp stoves to whistles to layered clothing, find out how to pack for your wilderness adventure—and why you should bring one luxury item on every trip.
Food and Water: Every expedition is a balance of caloric needs, creature comforts, and weight. The good news is that with appropriate water treatment, a few cooking essentials, and the right know-how at the campsite, you can eat in style without breaking your back on the trail or sinking the raft on the river.
Campsite Fundamentals: A good campsite is much more than a tent and sleeping bag. Professor Andre shows you how to arrange an outdoor kitchen, build a fire, set up a tarp, and minimize your impact on the terrain at camp—a courtesy your fellow outdoors enthusiasts will appreciate.
Navigation: It may sound flippant to say that the best way to avoid getting lost is always to know where you are. But by showing you how to read topographic maps and how to navigate with a compass, Professor Andre gives you the tools you need to keep your bearings.
In addition to her many tips for trip preparation, Professor Andre also offers guidance for what to do after you get home, from brushing off your tent for proper storage to stowing your sleeping bag so it will keep you warm on the next trip.
Learn How to Stay Safe in (Almost) Any Environment
One of the great appeals of an outdoor adventure is getting away from civilization. But getting away from society means help is not at the ready. If something goes wrong, you can’t dial 911 and get an EMT professional at your doorstep in a few short minutes. Dehydration, hypothermia, broken bones, snake bites, lightning strikes, starvation—the risks are there, but they can be minimized with a little preparation, care, and know-how.
Beyond packing the right gear, bringing plenty of food and a way to filter water, and taking care with your campsite, Professor Andre offers several practical lectures dedicated specifically to outdoor safety—which can be applied to everyday life as well—including lectures in:
Risk Assessment: When you read about avoidable accidents in the wild, your first thought might be, “What was this person thinking?” As you’ll discover, emotions play as big a role as reason in human decision-making, which can lead to dire consequences in the backcountry. But if you recognize your emotions taking over, you can better assess the risks in front of you.
Weather Analysis: Predicting rain is a neat parlor trick in the front country, but in the backcountry, a storm can mean life or death. Learn to analyze cloud patterns and recognize the warning signs of rain, lightning, tornadoes, and more. As you’ll discover, staying safe in severe weather isn’t always intuitive.
First Aid: From the big three (circulation, respiration, and the nervous system) to breaks, scrapes, burns, and bugs, you will gain insight into how to treat injuries from small mishaps to accidents—and when to call for an evacuation.
Many of the safety tips in this course boil down to planning ahead, paying attention to your surroundings, making good decisions, and exercising caution. Even something as simple as telling someone at home where you are going and when you’ll be back can be the difference between life and death. For instance, one of the most harrowing outdoor survival stories in recent years was made into the film 127 Hours, which tells the true story of a man who gets caught in a canyon in Utah. A simple note on his car at the trailhead might have saved him the worst week imaginable.
Deepen Your Appreciation of the Wild
Connecting with the natural world is what outdoor adventures are all about. It’s impossible to convey the experience of paddling down a river, climbing up a mountain, sleeping under the stars, or telling stories around a campfire. The pace of time changes, and you connect with something ancient inside yourself.
It’s an experience you must pursue in order to understand, but which anyone can simply enjoy. Whether you are thinking about an overnight car-camp at your local state park, a week-long canoe trip to the Minnesota Boundary Waters, or a months-long hike along the Appalachian Trail, Outdoor Fundamentals: Everything You Need to Know to Stay Safe will surely inspire you to get off the couch and into the wild.