TED-Ed

Dig into the mystery of Nicolas Bourbaki— one of the most influential mathematicians of all time… who never actually existed.--When Nicolas Bourbaki applied to the American Mathematical Society in the 1950s, he was already one of the most influential mathematicians of his time. He’d published articles in international journals and his textbooks were required reading. Yet his application was firmly...

View full lesson: http://ed.ted.com/lessons/defining-cyberwarfare-in-hopes-of-preventing-it-daniel-garrieCan you imagine a future where wars are fought not with bombs and bullets but computer viruses and pacemaker shutdowns? Cyberware is unique in that it is not covered by existing legal framework and it often inspires more questions than we are yet capable of answering. Daniel Garrie ponders some...

Get to know the science behind what causes the stiff, creaky joints of the most common forms of arthritis and what you can do to prevent it. --The bad backs, elbow pain, and creaky knees so common in older people often aren't just “old age.” In fact, the source of this stiffness plagues many young people as well. The culprit is arthritis: a condition that affects over 90 million people in the U.S....

Learn about the life and tragic death of gay rights pioneer Harvey Milk, California’s first openly gay public official.--By 1973, Harvey Milk had already been many things: naval officer, high school teacher, bit-part actor and wandering hippie. Starting fresh in San Francisco, his belief in a more personal approach to local government led him to run for office in the heart of American gay culture,...

Dig into Noam Chomsky’s theory of universal grammar and decide: are there universal grammar rules and are they hardwired into our brains?--Language is endlessly variable. Each of us can come up with an infinite number of sentences in our native language, and we’re able to do so from an early age— almost as soon as we start to communicate in sentences. How is this possible? In the early 1950s, Noam...

View full lesson: http://ed.ted.com/lessons/the-walk-from-no-to-yes-william-ury William Ury, author of "Getting to Yes," offers an elegant, simple (but not easy) way to create agreement in even the most difficult situations -- from family conflict to, perhaps, the Middle East. (Filmed at TEDxMidWest.) Talk by William Ury. Learn more about your ad choices. Visit megaphone.fm/adchoices

View full lesson: http://ed.ted.com/lessons/the-chemistry-of-cookies-stephanie-warrenYou stick cookie dough into an oven, and magically, you get a plate of warm, gooey cookies. Except it's not magic; it's science. Stephanie Warren explains via basic chemistry principles how the dough spreads out, at what temperature we can kill salmonella, and why that intoxicating smell wafting from your oven ind...

View full lesson: http://ed.ted.com/lessons/mysteries-of-vernacular-lady-jessica-oreck-and-rachael-teelWhy do we call women ladies? Well, etymologically-speaking, the word comes from the Old English words for hlaf (bread) and daege (maid), which, combined, mean the female head of the household and eventually indicated high social standing. Jessica Oreck and Rachael Teel follow the word to its cont...

View full lesson: http://ed.ted.com/lessons/all-of-the-energy-in-the-universe-is-george-zaidan-and-charles-mortonThe energy in the universe never increases or decreases -- but it does move around a lot. Energy can be potential (like a stretched-out rubber band waiting to snap) or kinetic (like the molecules that vibrate within any substance). And though we can't exactly see it, every time we cook...

View full lesson: http://ed.ted.com/lessons/a-brief-history-of-religion-in-art-ted-edBefore we began putting art into museums, art mostly served as the visual counterpart to religious stories. Are these theological paintings, sculptures, textiles and illuminations from centuries ago still relevant to us? Jeremiah Dickey describes the evolution of art in the public eye and explains how the modern v...

Get to know the story of Quanah Parker, a Native American warrior and leader, and the last chief of the Comanche tribe. --Late one night in 1871, a group of riders descended on a sleeping army camp, stole about 70 horses, and disappeared. Led by a young chief named Quanah Parker, the raid was the latest in a long series of altercations along the Texas frontier between indigenous people and United...

View full lesson: http://ed.ted.com/lessons/the-arctic-vs-the-antarctic-camille-seamanHow can you tell the two poles apart? Where are the penguins? What about the bears? The Arctic pole is located in the Northern Hemisphere within the deep Arctic Ocean, while the Antarctic pole is smack in the middle of the ice-covered Antarctica. Camille Seaman describes how enterprising people and organisms have...

What makes a tree grow tall? And do trees ever stop growing? Explore how photosynthesis and gravity can affect and limit the height of trees. --Reaching heights of over 100 meters, Californian sequoias tower over Earth’s other 60,000 tree species. But even these behemoths seem to have their limits: no sequoia on record has been able to grow taller than 130 meters. So what exactly is stopping these...

Dive into the Taino myth of the sea, and watch as Deminan and his brothers accidentally create a new world from a giant gourd. --Before the world of humans began, there was the world of the gods. Four brothers wandered this celestial realm. One day, the brothers snuck into a spirit’s house and spotted a giant gourd hanging in the corner. But as they tried to look inside the gourd, they dropped it....

Dig into the science of how new volcanoes form, and what causes their unpredictable eruptions. --In February of 1942, Mexican farmer Dionisio Pulido thought he heard thunder coming from his cornfield. However, the sound wasn’t coming from the sky. The source was a large, smoking crack emitting gas and ejecting rocks, and would come to be known as the volcano Paricutin. Where do new volcanoes like...

Discover how evolution and natural selection influence why the human body has vestigial organs— body parts that no longer serve their original purpose. --You know that little pink thing nestled in the corner of your eye? It’s actually the remnant of a third eyelid. In humans, it’s vestigial, meaning it no longer serves its original purpose. There are several other vestigial structures in the human...

View full lesson: http://ed.ted.com/lessons/tycho-brahe-the-scandalous-astronomer-dan-wenkelIf you think scientists lead boring, monotonous lives, you must not know about Tycho Brahe. The 16th century astronomer who accurately predicted planetary motion led quite a dramatic life -- complete with a kidnapping, a sword duel and even a clairvoyant dwarf. Dan Wenkel dives into the history behind this...

Discover the tale of the lovestruck boy sent into Hell to steal 3 hairs from the Devil to appease his true love's father, the king.--In a small town, a proud mother showed off her newborn son. Upon noticing his lucky birthmark, townsfolk predicted he would marry a princess. But soon, these rumors reached the wicked king. Enraged, the king stole the child away, and sent him hurtling down the river....

View full lesson: http://ed.ted.com/lessons/the-chemical-reaction-that-feeds-the-world-daniel-d-dulekHow do we grow crops quickly enough to feed the Earth's billions? It's called the Haber process, which turns the nitrogen in the air into ammonia, easily converted in soil to the nitrate plants need to survive. Though it has increased food supply worldwide, the Haber process has also taken an unfor...

Dig into the Egyptian myth of Osiris, trapped by his brother, the warrior god Set, in a coffin and tossed into the Nile to die. --Long jealous of his older brother Osiris, the god who ruled all of Egypt, the warrior god Set plotted to overthrow him. Hosting an extravagant party as a ruse, Set announced a game— whoever could fit perfectly in a wooden chest could have it as a gift. But the chest was...

Dig into the mysterious Linear B symbols, found on ancient tablets on the island of Crete, which took scholars nearly 50 years to decode.--In the early 1900s, archaeologist Sir Arthur Evans uncovered nearly 3,000 tablets inscribed with strange symbols. He thought the script, dubbed Linear B, represented the Minoan language, while others came up with their own theories. Was it the lost language of...

A shooting star crashes onto Earth and unleashes a hideous, rampaging blob. Can you stop it from destroying the planet?--A shooting star crashes onto Earth and a hideous blob emerges. It creeps and leaps, it glides and slides. It’s also unstoppable: no matter what you throw at it, it just re-grows and continues its rampage. The only way to save the planet is to cut the entire blob into precise acu...

Trace the rise and fall of the ancient Celts, a group of hundreds of independent warrior tribes defeated by the Roman Empire. --One summer evening in 335 BCE, Alexander the Great was resting by the Danube River when a band of strangers approached his camp. Alexander had never seen anything like these tall, fierce-looking warriors with huge golden neck rings and colorful cloaks. They were Keltoi or...

View full lesson: http://ed.ted.com/lessons/the-operating-system-of-life-george-zaidan-and-charles-mortonHumans, octopi and pine trees alike are all made up of cells, tiny but sophisticated systems that keep life going. Cells are almost like tiny factories run by robots, with the nucleus, DNA, proteins, lipids, and vitamins and minerals all playing critical roles. George Zaidan and Charles Morton...

View full lesson: http://ed.ted.com/lessons/why-is-yawning-contagious-claudia-aguirre*Yaaawwwwwn* Did just reading the word make you feel like yawning yourself? Known as contagious yawning, the reasons behind this phenomenon have been attributed to both the physiological and psychological. It's been observed in children as young as four and even in dogs! Claudia Aguirre visits the many intriguing...