Logic is intellectual self-defense against such assaults on reason and also a method of quality control for checking the validity of your own views. But beyond these very practical benefits, informal logic—the kind we apply in daily life—is the gateway to an elegant and fascinating branch of philosophy known as formal logic, which is philosophy’s equivalent to calculus. Formal logic is a breathtakingly versatile tool. Much like a Swiss army...

In 1872, a wondrous region called Yellowstone was set aside as the world’s first national park, giving adventurous travelers access to a geologist’s paradise that seethes with pent-up volcanic forces. As more and more national parks were created—not just in the United States but also in Canada and Mexico—geologists were revolutionizing their field, piecing together a detailed understanding of how the world works. National parks have made these...

Where is energy commonly being wasted? How does one become a more efficient energy user? This lecture is filled with takeaways to help anyone (from home owner to car driver to CEO) become more energy efficient in a range of sectors and settings: industries, transportation, residences, and commercial buildings.

By the time of European contact, the Aztec empire was the most extensive in Mesoamerican history. Study the Aztecs' methodical approach to conquest and the structure of their empire, which was more like Alexander the Great's than imperial Rome's.

One stereotype science fiction still hasn’t fully shaken off is that it is a predominantly male genre. Originally, the audience was assumed to be male because science fiction often featured similar themes of exploration, war, and domination that characterized the Western genre. This idea was so prevalent that female science fiction writers were often only successful when writing under a male pseudonym or gender-ambiguous nom de plume. Look at how...

Learn about the creation of Elgar’s exquisite and very Catholic oratorio, against the musical and religious backdrop of 19th-century Britain. Study how Elgar infused The Dream of Gerontius with Wagnerian operatic elements such as continuous musical narrative, leitmotif, and lavish orchestration, transforming the genre of oratorio into something new..

Tour Mount Rainier National Park and Lassen Volcanic National Park in the Pacific Northwest, which are part of the Cascade Range of active volcanoes that include Mount Saint Helens. Then visit a group of similarly cataclysmic volcanoes in national parks in central Mexico..

Investigate positive polarity lighting—a bolt up to ten times more powerful than normal lightning—which accounts for five percent of cloud-to-ground strikes. Then hear life-saving tips on how to recognize when you are about to be hit by lightning and what you should instantly do.

A huge challenge in robotics is getting robots to work as a team to do things they can’t do alone. Enter swarm robots: simple, similar mobile robots that combine to generate complex behaviors. Investigate this area of robotics that’s barely in its infancy, but has vast potential for scientific research, military defense, and more..

With Fundamentals of Photography, you'll learn everything you need to know about the art and craft of great photography straight from Joel Sartore, a National Geographer photographer with more than 30 years of experience. Designed for people at all levels, these 24 episodes are an engaging guide to how photographs work and how to make them work better for you.