"The Big Sink"

In this episode, John and Katie take a break from talking through the universe's timeline to focus on a mystery of our cosmos: black holes.

In which John Green kicks off Crash Course US History! Why, you may ask, are we covering US History, and not more World History, or the history of some other country, or the very specific history of your home region? Well, the reasons are many. But, like it or not, the United States has probably meddled in your country to some degree in the last 236 years or so, and that means US History is relevant all over the world. In episode 1, John talks about the Native Americans who lived in what is now the US prior to European contact. This is a history class, not archaeology, so we're mainly going to cover written history. That means we start with the first sustained European settlement in North America, and that means the Spanish. The Spanish have a long history with the natives of the Americas, and not all of it was positive. The Spanish were definitely not peaceful colonizers, but what colonizers are peaceful? Colonization pretty much always results in an antagonistic relationship with the locals. John teaches you about early Spanish explorers, settlements, and what happened when they didn't get along with the indigenous people. The story of their rocky relations has been called the Black Legend. Which is not a positive legend.

Chapters:
Introduction to Crash Course US History
Native North Americans
Were Native North Americans 'Primitive?'
Native North American Populations
Life in Pre-Columbian America
Class and Society in Native American Tribes
Spanish Colonization in North America
Mystery Document
The Problem with the Black Legend
Credits

In the final episode of Crash Course Black American History, Clint Smith teaches you about the Black Lives Matter movement. We'll discuss some of the major events that contributed to the rise of BLM, including the deaths of Trayvon Martin, Michael Brown, Eric Garner, and George Floyd, and the way that social media was utilized by Black organizers to gain support for the movement.

Many organizations have made it their mission to expand the rights of Black Americans. The NAACP and the Urban League are examples of influential organizations with long histories. But a long history or extensive membership isn't always necessary to have an impact. Today, we'll learn about the Black Panthers. They were a relatively small, relatively short-lived political party that had an outsized impact on US history.

In the late 19th and early 20th centuries, Black American Women were struggling with both racism and misogyny as they fought for their rights. Black Women formed clubs and organized to make sure civil and political rights were extended to ALL Black people, not just Black men. These clubs were grass-roots organizations of middle-class women who were often only one generation removed from slavery. Today we'll learn about the origins of these clubs and some of the notable women who drove this movement.

Now that we've talked about your blood vessels, we're going to zoom in a little closer and talk about your blood itself. We'll start by outlining the basic components of blood -- including erythrocytes, leukocytes, platelets, and plasma -- as well as the basic process of hemostasis that stops bleeding, and how antigens are responsible for the blood type that you have. By the end of this episode, you should be totally prepared for your next blood drive.

Chapters:
Introduction: Let's Talk Blood
How Blood Donation Works
Blood Components: Erythrocytes, Leukocytes, Platelets, and Plasma
Plasma - Electrolytes
Plasma Proteins
Hemostasis: How Bleeding Works
Antigens & Blood Types
Review
Credits

It's time to start talking about some of the terrible things you can do to your own body, like blood doping. We'll start by explaining the structure and function of your erythrocytes, and of hemoglobin, which they use to carry oxygen. We'll follow the formation and life cycle of a red blood cell, including how its levels are regulated by EPO and its signaling molecules. We'll wrap up by looking at how blood doping works and how it is truly a recipe for disaster.

Chapters:
Introduction: Blood is Powerful Stuff
Form and Function of Erythrocytes (Red Blood Cells)
Hemoglobin
Formation of a Red Blood Cell: Hematopoiesis
How Erythropoietin (EPO) Regulates Blood Oxygen Levels
How Red Blood Cells Die
Don't Dope Your Blood!
Review
Credits

Now that we've discussed blood, we're beginning our look at how it gets around your body. Today Hank explains your blood vessels and their basic three-layer structure of your blood vessels. We're also going over how those structures differ slightly in different types of vessels. We will also follow the flow of blood from your heart to the capillaries in your right thumb, and all the way back to your heart again.

Chapters:
Introduction: The Circulatory System
Blood Vessel Structure: Tunica Intima, Tunica Media, Tunica Externa
Types of Blood Vessels
Capillaries Structure & Function
How Blood Flows From Capillaries to the Heart
Review
Credits

And now we return to blood vessels. In this episode, we start discussing what blood pressure is, how it can become "high", and what that means for our health. One of the more interesting points is that your body has ways of dealing with high blood pressure, but they're not ways we want our bodies to operate on a full-time basis. And why can't we butter our bacon? WHY!?!?!

Chapters:
Introduction: High Blood Pressure
Cardiac Output - How Blood Flows
Blood Pressure & Resistance
Blood Flow Formula
Short Term Blood Pressure Regulation
Long Term Blood Pressure Regulation
Chronic High Blood Pressure
Review
Credits

Today, we’re going to talk about board games, but instead of trying to trace their histories, which we’ve already covered a bit of in ep2 on ancient games, we’re going to look really closely at just two board games - Monopoly and The Settlers of Catan. These two games have been played by millions, and we’ll talk about why they’re so popular (and controversial), but more importantly these two games have helped define two approaches to board game design: the American style board game and the European style board game. Now these two different “styles” of board games are mostly just over-generalizations about board game mechanics and there’s a ton of overlap, but with the recent resurgence in board game popularity they help us more clearly define two discrete time periods in board game popularity and discuss how these approaches have been defined by the times.

In this episode of Crash Course Psychology, Hank talks about how we learn by observation... and how that can mean beating up an inanimate clown named Bobo.

Chapters:
Introduction: The Bobo Doll Experiment
Social Cognitive Learning
Limitations of Classical & Operant Conditioning
Learning Associations
Learning & Cognition
Latent Learning
Observational Learning, Modeling, & Imitation
Reward Pathways & Mirror Neurons
Observational Social Learning
Review & Credits
Credits

After World War Two, the applications of basic discoveries in biology took off—and became big business. Today, we’ll look at the rise of Big Pharma and GMO foods. We’ll also discuss how life-science technologies fundamentally changed reproduction: it’s time to invent In Vitro Fertilization and clone a sheep!

In this episode of Crash Course Art History, we’ll hold a mirror to our bodies…in art, anyway. We’ll learn what portraits and self-portraits can tell us about the people they represent and about artists who’ve used bodies to critique their societies.
Chapters:
Introduction: We All Have Bodies
Portraits & Self-Portraits
European Art & the Nude Figure
"Becoming an Image"
"Olympia"
Review & Credits
Credits

Models are great, except they're also usually inaccurate. In this episode of Crash Course Chemistry, Hank discusses why we need models in the world and how we can learn from them... even when they're almost completely wrong. Plus, Lewis Structures!

Chapters:
Models
Linus Pauling & The Bonding Model
Lewis Dot Structures
Ionic Bonds
Covalent Bonds
Double Bonds
Triple Bonds

As the 19th century gave way to the 20th, Black Americans were searching for ways to think about how and where they would fit into a post-slavery society. There were several competing schools of thought. Booker T. Washington and W.E.B. Dubois were essential to some of the most prominent ideas in this arena.

Today, Carrie Anne is going to take a look at how those transistors we talked about last episode can be used to perform complex actions. With the just two states, on and off, the flow of electricity can be used to perform a number of logical operations, which are guided by a branch of mathematics called Boolean Algebra. We’re going to focus on three fundamental operations - NOT, AND, and OR - and show how they were created in a series of really useful circuits. And its these simple electrical circuits that lay the groundwork for our much more complex machines.

*CORRECTION* AT the graph says "Quinary System" but then the graph shows 10 possible states - which is actually decimal. Technically, there should be only 5 possible values there, but the overall concept is still the same.

In this episode of Crash Course Psychology, Hank takes a look at WAIS and WISC intelligence tests and how bias can really skew both results and the usefulness of those results.

Chapters:
Introduction
WAIS & WISC Tests
Standardized Tests
Reliability & Validity
Twin & Adoption Studies - Genetics of Intelligence
Environmental Influences on Intelligence
Testing Bias
Stereotype Threat
Review & Credits
Credits

Today we're going to take a closer look at brains, how animals use them, and how some animals have even evolved to lose them! It turns out a brain (and intelligence more broadly) isn't easy to define, but what we do know for sure is that brains have evolved over time in response to the challenges in an animals' environment. And what we'll find is that sometimes it's much smarter to have a tiny, simple brain than a big, complicated one!

Nothing changed movies like the arrival of synchronous sound. NOTHING! Acting, directing, cinematography, and presentation all had to be rethought. Some studios were more quick to take on the challenge while others waited until the last moment. Some actors made graceful transitions while others struggled with the new format. But this was the big turning point and a major completion point to what movies would ultimately become.

Thanks to the wonders of physics, astronomers can map a timeline of the universe’s history. Today, Phil’s going to give you an overview of those first few minutes (yes, MINUTES) of the universe’s life. It started with the Big Bang when the Universe was incredibly dense and hot. It expanded and cooled, going through multiple stages where different kinds of matter could form. It underwent a phenomenally rapid expansion called inflation, which smoothed out much of the lumpiness in the matter. Normal matter formed atoms between 3 and 20 minutes after the bang, and the lumps left over from inflation formed the galaxies and larger structures we see today.

Chapters:
Introduction: The History of the Universe
Giant Particle Colliders
Phase Changes
After the Big Bang: The First Minutes
Recombination
Inflation
Unanswered Questions in Astronomy
Review