We used to think that the human brain was a lot like a computer; using logic to figure out complicated problems. It turns out, it's a lot more complex and, well, weird than that. In this episode of Crash Course Psychology, Hank discusses thinking & communication, solving problems, creating problems, and a few ideas about what our brains are doing up there.

Chapters:
Introduction: Cognition
Concepts & Prototypes
Prejudice
Solving Problems: Algorithms & Heuristics
Neurology of Problem Solving
Confirmation Bias & Belief Perseverance
Mental Sets & the Availability Heuristic
Framing
Review & Credits
Credits

In which John Green teaches you about the Cold War, the decades-long conflict between the USA and the USSR. The Cold War was called cold because of the lack of actual fighting, but this is inaccurate. There was plenty of fighting, from Korea to Viet Nam to Afghanistan, but we'll get into that stuff next week. This week we'll talk about how the Cold War started. In short, it grew out of World War II. Basically, the Soviets occupied Eastern Europe and the US-supported western Europe. This setup would spill across the world, with client states on both sides. It's all in the video. You should just watch it.

Chapters:
Introduction: The Cold War Era
The Aftermath of WWII
USSR Expansion & Containment
The Truman Doctrine
The Marshall Plan
The Berlin Crisis
Mystery Document
Consensus on Cold War Policies
Impact of the Cold War on Domestic Policy
Espionage, McCarthyism, and the Red Scare
Credits

Today we’re going to step back from hardware and software, and take a closer look at how the backdrop of the cold war and space race and the rise of consumerism and globalization brought us from huge, expensive codebreaking machines in the 1940s to affordable handhelds and personal computers in the 1970s. This is an era that saw huge government funded projects - like the race to the moon. And afterward, a shift towards the individual consumer, commoditization of components, and the rise of the Japanese electronics industry.

In which John Green teaches you about the Cold War as it unfolded in Asia. As John pointed out last week, the Cold War was occasionally hot, and a lot of that heat was generated in Asia. This is starting to sound weird with the hot/cold thing, so let's just say that the United States' struggle against communist expansion escalated to a full-blown, boots-on-the-ground war in Korea and Vietnam. In both of these cases, the United States sent soldiers to intervene in civil wars that it looked like communists might win. That's a bit of a simplification, but John will explain it all to you.

Chapters:
Introduction: The Cold War in Asia
The Korean War
Eisenhower's Election
Cost of the Korean War
Mystery Document
Ho Chi Minh
American Involvement in Vietnam
The Gulf of Tonkin Incident
Operation Rolling Thunder
Fighting in Vietnam
Public Opinion and the Vietnam War
Nixon's Plan to Leave Vietnam
Anti-War Sentiments
The End of the Vietnam War
Credits

COLLISIONS! A big part of physics is understanding collisions and how they're not all the same. Mass, momentum, and many other things dictate how collisions can be unique. In this episode of Crash Course Physics, Shini sits down to lead us through an understanding of collisions. Plus, she brings along our old friend Sir Isaac Newton.

Empire, imperialism, and colonialism are all interrelated tactics of geopolitics that are used to achieve similar goals of one state maintaining economic, political, or even cultural dominance over other territories. Today, we’re going to unravel the impacts of colonialism at different times throughout history from Taiwan to Myanmar as we examine the longstanding impacts of these relationships. We’ll also take a look at how some countries today, like Thailand, have taken the control of the narrative through culinary colonization.

Over the last four episodes, we’ve examined some of the stories that make up the idea of a “revolution” in knowledge-making in Europe. But we can’t understand this idea fully, without unpacking another one—the so called Age of Exploration. This encompasses a lot of events that happened from 1400 through the 1600s and were driven in part by new ideas about knowledge-making.

In which John Green teaches you about the changes wrought by contact between the Old World and the New. John does this by exploring the totally awesome history book "The Columbian Exchange" by Alfred Crosby, Jr. After Columbus "discovered" the Americas, European conquerors, traders, and settlers brought all manner of changes to the formerly isolated continents. Disease and invasive plant and animal species remade the New World, usually in negative ways. While native people, plants, and animals were being displaced in the Americas, the rest of the world was benefitting from American imports, especially foods like maize, tomatoes, potatoes, pineapple, blueberries, sweet potatoes, and manioc. Was the Columbian Exchange a net positive? It's debatable. So debate.

Chapters:
Introduction: The Columbian Exchange
Diseases of the Columbian Exchange
John Green Does the Cinnamon Challenge (Ew)
An Open Letter to Tobacco
Animals of the Columbian Exchange
Plants of the Columbian Exchange
People of the Columbian Exchange
Credits

In which John Green teaches you about the beginning of the so-called Age of Discovery. You've probably heard of Christopher Columbus, who "discovered" America in 1492, but what about Vasco da Gama? How about Zheng He? Columbus gets a bad rap from many modern historians, but it turns out he was pretty important as far as the history of the world goes. That said, he wasn't the only pioneer plying the seas in the 1400s. In Portugal, Vasco da Gama was busy integrating Europe into the Indian Ocean Trade by sailing around Africa. Chinese admiral Zheng He was also traveling far and wide in the largest wooden ships ever built. Columbus, whether portrayed as a hero or a villain, is usually credited as the great sailor of the 15th century, but he definitely wasn't the only contender. What better way to settle this question than with a knock-down, drag-out, no holds barred, old-fashioned battle royal? We were going to make it a cage match, but welding is EXPENSIVE.

Chapters:
Introduction
Notable Sailors of the 15th Century
Zheng He, Chinese Admiral
Reasons for China's 15th Century Naval Expeditions
Vasco da Gama, Portuguese Explorer
Vasco da Gama's Motivations and Strategies
Myths about Christopher Columbus
An Open Letter to the Line of Demarcation
Christopher Columbus's First Voyage
Who Was the Greatest Mariner of the 15th Century?
Credits

This week we're continuing our discussion of William Shakespeare and looking at his comedies and romances. As well as something called problem plays. Some of his plays, they had problems. We'll also put on pants, escape to forest, and talk about Shakepeare's heroines, lots of whom had quite a bit more agency in these plays than the women in the tragedies had.

Today on Crash Course Astronomy, Phil explains comets. Comets are chunks of ice and rock that orbit the Sun. When they get near the Sun the ice turns into gas, forming the long tail, and also releases dust that forms a different tail. We’ve visited comets up close and found them to be lumpy, with vents on the surface that release the gas as ice sublimates. Eons ago, comets (and asteroids) may have brought a lot of water to Earth -- as well as the ingredients for life.

Chapters:
Introduction: Comets
Comets = Dirty Snowballs
Comets Have Two Tails
Short-Term vs Long-Term Comets
Where do comets come from?
Comets Up-Close
What Happens When Comets Hit Earth?
Review

We've been talking a lot about kings, and queens, and wars, and religious upheaval for most of this series, but let's take a moment to zoom out, and look at the ways that individuals' lives were changing in the time span we've covered so far. Some people's lives were improving, thanks to innovations in agriculture and commerce, and the technologies that drove those fields. Lots of people's lives were also getting worse during this time, thanks to the expansion of the Atlantic slave trade. And these two shifts were definitely intertwined.

In which John Green teaches you about China's Revolutions. While the rest of the world was off having a couple of World Wars, China was busily uprooting the dynastic system that had ruled there for millennia. Most revolutions have some degree of tumult associated with them, but China's 20th-century revolutions were REALLY disruptive. In 1911 and 1912, Chinese nationalists brought 3000 years of dynastic rule to an end. China plunged into chaos as warlords staked out regions of the country for themselves. The nationalists and communists joined forces briefly to bring the nation back together under the Chinese Republic, and then they quickly split and started fighting the Chinese Civil War. The fight between nationalists and communists went on for decades and was interrupted by an alliance to fight the invading Japanese during World War II. After World War II ended, the Chinese Civil War was back on. Mao and the communists were ultimately victorious, and Chiang Kai-Shek ended up in Taiwan. And then it got weird. Mao spent years repeatedly trying to purify the Communist Party and build up the new People's Republic of China with Rectifications, Anti Campaigns, Five Year Plans. the Great Leap Forward, and the Cultural Revolution. These had mixed results, to say the least. John will cover all this and more in this week's Crash Course World History.

Chapters:
Introduction: China's Revolutions
Calls for Reform in China
An Open Letter to Sun Yat Sen
Overthrowing the Qing Dynasty
The Guomindang and the Chinese Communist Party
Mao Establishes the People's Republic of China
China's Soviet-inspired Five Year Plans
China's Cultural Revolution
Credits

Interactions between species are what define ecological communities, and community ecology studies these interactions anywhere they take place. Although interspecies interactions are mostly competitive, competition is pretty dangerous, so a lot of interactions are actually about side-stepping direct competition and instead finding ways to divvy up resources to let species get along. Feel the love?

Chapters:
1) Competitive Exclusion Principle
2) Fundamental vs. Realized Niche
3) Eco-lography / Resource Partitioning
4) Character Displacement
5) Mutualism
6) Commensalism

Hank gets to the more violent part of community ecology by describing predation and the many ways prey organisms have developed to avoid it.

Chapters:
Herbivory and Parasitism
Predatory Adaptation
Cryptic Coloration
Mullerian Mimicry
Batesian Mimicry

Community ecology is the study of interactions between different species of living things, and lets ecologists examine the effects of predator-prey relationships, parasites, and mutually beneficial interactions. In this episode of Crash Course Biology, we’ll examine the myriad interspecies interactions with examples, see how keystone species impact their environment and explore how communities rebuild when they are disrupted, through the lens of the 1980 eruption of Mount St. Helens.

Chapters:
Community Ecology
Community Disturbances
Interspecies Interactions
Competition
Community Regulation
Review & Credits
Credits

Hank introduces us to comparative anatomy, which studies the similarities and differences in animal anatomy to support the theory of evolution and the shared ancestry of living things.

Chapters:
1) Comparative Anatomy
2) Locomotion
3) Heterotophy
4) Convergent Evolution
5) Biolography
6) Tissues
a) Epithelial Tissue
b) Connective Tissue
c) Muscle Tissue
d) Nerve Tissue
7) Organs
8) Organ Systems
Review

As we continue explore free will, today Hank considers a middle ground between hard determinism and libertarian free will: compatibilism. This view seeks to find ways that our internally motivated actions can be understood as free in a deterministic world. We’ll also cover Frankfurt Cases and Patricia Churchland’s rejection of the free-or-not-free dichotomy and her focus on the amount of control we have over our actions.

Hank continues our exploration of animal phyla with the more complexly organized annelida and arthropoda, and a biolography on insects.

So last episode we talked about some basic file formats, but what we didn’t talk about is compression. Often files are way too large to be easily stored on hard drives or transferred over the Internet - the solution, unsurprisingly, is to make them smaller. Today, we’re going to talk about lossless compression, which will give you the exact same thing when reassembled, as well as lossy compression, which uses the limitations of human perception to remove less important data. From listening to music and sharing photos, to talking on the phone and even streaming this video right now the ways we use the Internet and our computing devices just wouldn’t be possible without the help of compression.