What is an underground economy? Whether you call it a black market, a grey market, or just the shop down the street, its about connecting people with goods outside of official channels. Some stuff happens in the underground economy because it's illegal, but a lot of the money that moves around this way is exchanged for pretty mundane goods and services. We'll talk about how these things work, and the awesome ways that economists figure out where all that money is.

So we've all heard of relativity, right? But... what is relativity? And how does it relate to light? And motion? In this episode of Crash Course Physics, Shini talks to us about perspective, observation, and how relativity is REALLY weird!
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Produced in collaboration with PBS Digital Studios: http://youtube.com/pbsdigitalstudios

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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.

Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App!

Download it here for Apple Devices: https://apple.co/3d4eyZo
Download it here for Android Devices: https://bit.ly/2SrDulJ

Chapters:
Introduction: Blood is Powerful Stuff 00:00
Form and Function of Erythrocytes (Red Blood Cells) 1:34
Hemoglobin 2:30
Formation of a Red Blood Cell: Hematopoiesis 4:11
How Erythropoietin (EPO) Regulates Blood Oxygen Levels 5:43
How Red Blood Cells Die 6:54
Don't Dope Your Blood! 7:53
Review 9:00
Credits 9:35

***

Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse

Thanks to the following Patrons for their generous monthly contributions that help keep Crash Course free for everyone forever:

Mark, Jan Schmid, Simun Niclasen, Robert Kunz, Daniel Baulig, Jason A Saslow, Eric Kitchen, Christian, Beatrice Jin, Anna-Ester Volozh, Eric Knight, Elliot Beter, Jeffrey Thompson, Ian Dundore, Stephen Lawless, Today I Found Out, James Craver, Jessica Wode, Sandra Aft, Jacob Ash, SR Foxley, Christy Huddleston, Steve Marshall, Chris Peters

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This week Craig Benzine explores the leadership structure of congress. We’ll break out the clone machine to examine the responsibilities of the speaker of the house, the majority and minority leaders, and the majority and minority whips in both the Senate and the House. As the leadership heavily influences assignments to committees and acts as the primary point of contact with the media, they wield significant power in influencing public dialog.

Produced in collaboration with PBS Digital Studios: http://youtube.com/pbsdigitalstudios
Support is provided by Voqal: http://www.voqal.org

Chapters:
Introduction: Leadership Structure of Congress 00:00
Leadership in Congress 0:22
Speaker of the House 0:50
Majority & Minority Whips & Leaders 1:20
Senate leadership 2:05
How congressional leaders exercise power 3:03
Who controls the congressional agenda? 3:28
Access to press 4:13
Fundraising 4:43
Why political parties matter in Congress 5:26
Understanding congressional leadership 6:54
Credits 7:39

Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse

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Now that we’ve left behind the philosophy of religion, it’s time to start exploring what other ways might exist to find meaning in the world. Today we explore essentialism and its response: existentialism. We’ll also learn about Jean-Paul Sartre and his ideas about how to find meaning in a meaningless world.

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Taylor Swift drawing by Joezart: http://joezart.deviantart.com/....art/Taylor-Swift-569 Graduate and proud parents by Christopher Brown: https://www.flickr.com/photos/....xopherbrown/56211258
All other images and video either public domain or via VideoBlocks, Unsplash, or Wikimedia Commons, licensed under Creative Commons BY 4.0: https://creativecommons.org/licenses/by/4.0/

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Produced in collaboration with PBS Digital Studios: http://youtube.com/pbsdigitalstudios

Crash Course Philosophy is sponsored by Squarespace.
http://www.squarespace.com/crashcourse

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This week Craig continues our conversation on presidential powers by looking at those NOT found in the Constitution - implied or inherent powers. We’ll talk about how the President uses their power to negotiate executive agreements, recommend legislative initiatives, instate executive orders, impound funds, and claim executive privilege in order to get things done. Implied powers are kind of tough to tack down, as they aren’t really powers until they’re asserted, but once they are, most subsequent Presidents chose not to give them up. So we’ll try to cover those we’ve seen so far and talk a little bit about reactions to these sometimes controversial actions from the other branches of Congress.

Support is provided by Voqal: http://www.voqal.org
This episode is sponsored by Squarespace: http://www.squarespace.com/crashcourse

Chapters:
Introduction: Informal Powers of the President 00:00
Informal powers of the President 0:50
Inherent power to use troops 1:20
War Powers Resolution 2:23
Executive agreements vs. treaties 2:42
CEO of the U.S. 3:31
Legislative Initiative 4:18
Executive orders 5:20
Impounding funds 6:02
Executive privilege 6:20
The importance of presidential precedent 6:56
Credits 7:21

Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse

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This episode is sponsored by Audible. Try Audible: http://audible.com/crashcourse

Why is it hard to move a heavy bookcase across a carpeted floor? And why is it easier to keep it moving than it was to get it started moving? You might think it's all about weight, but actually it's about friction. Two kinds of friction! In today's episode of Crash Course Physics, Shini Somara tells us about Static and Kinetic friction; how they work and how they're different.


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Produced in collaboration with PBS Digital Studios: http://youtube.com/pbsdigitalstudios


Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse

Thanks to the following Patrons for their generous monthly contributions that help keep Crash Course free for everyone forever:

Mark, Eric Kitchen, Jessica Wode, Jeffrey Thompson, Steve Marshall, Moritz Schmidt, Robert Kunz, Tim Curwick, Jason A Saslow, SR Foxley, Elliot Beter, Jacob Ash, Christian, Jan Schmid, Jirat, Christy Huddleston, Daniel Baulig, Chris Peters, Anna-Ester Volozh, Ian Dundore, Caleb Weeks


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Slave codes were a method of protecting the investment of white enslavers in the Colonies by restricting the lives of enslaved people in almost every imaginable way. The codes restricted enslaved people’s ability to move around, or engage in commerce that could make them financially independent - they restricted the opportunities that would allow them to live with even relative freedom. Today, we'll learn how Colonies put laws in place to restrict the movement and freedoms of enslaved people and free Black people.

VIDEO SOURCES

Ira Berlin, Many Thousands Gone: The First Two Centuries of Slavery in North America (Cambridge: Harvard University Press, 1998).
John Hope Franklin, From Slavery to Freedom: A History of Negro Americans (New York: Knopf, 1967).
Claude M. Steele, Whistling Vivaldi: How Stereotypes Affect Us and What We Can Do (Reprint Edition ed. 2011).
Black Codes and Slave Codes, Colonial, , Oxford African American Studies Center , http://oxfordaasc.com/view/10.....1093/acref/978019530
Peter H. Wood, Black Majority: Negroes in Colonial South Carolina from 1670 through the Stono Rebellion (New York: W.W. Norton, 1974).
Jennifer L. Morgan, Partus sequitur ventrem: Law, Race, and Reproduction in Colonial Slavery, 22 Small Axe: A Caribbean Journal of Criticism 1–17 (2018).

Watch our videos and review your learning with the Crash Course App!
Download here for Apple Devices: https://apple.co/3d4eyZo
Download here for Android Devices: https://bit.ly/2SrDulJ

Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse

Check out Clint's book: https://bookshop.org/books/how....-the-word-is-passed-

Thanks to the following patrons for their generous monthly contributions that help keep Crash Course free for everyone forever:

Alexis B, Rene Duedam, Burt Humburg, Aziz, Nick, DAVID MORTON HUDSON, Perry Joyce, Scott Harrison, Mark & Susan Billian, Junrong Eric Zhu, Alan Bridgeman, Jennifer Smith, Matt Curls, Tim Kwist, Jonathan Zbikowski, Jennifer Killen, Sarah & Nathan Catchings, Brandon Westmoreland, team dorsey, Trevin Beattie, Eric Koslow, Indika Siriwardena, Khaled El Shalakany, Shawn Arnold, Siobhán, Ken Penttinen, Nathan Taylor, William McGraw, Laura Damon, Andrei Krishkevich, Sam Ferguson, Eric Prestemon, Jirat, Brian Thomas Gossett, Wai Jack Sin, Ian Dundore, Jason A Saslow, Justin, Jessica Wode, Mark, Caleb Weeks
__

VIDEO SOURCES

-Ira Berlin, Many Thousands Gone: The First Two Centuries of Slavery in North America (Cambridge: Harvard University Press, 1998).
-John Hope Franklin, From Slavery to Freedom: A History of Negro Americans (New York: Knopf, 1967).
-Claude M. Steele, Whistling Vivaldi: How Stereotypes Affect Us and What We Can Do (Reprint Edition ed. 2011).
-Black Codes and Slave Codes, Colonial, , Oxford African American Studies Center , http://oxfordaasc.com/view/10.....1093/acref/978019530
-Peter H. Wood, Black Majority: Negroes in Colonial South Carolina from 1670 through the Stono Rebellion (New York: W.W. Norton, 1974).
-Jennifer L. Morgan, Partus sequitur ventrem: Law, Race, and Reproduction in Colonial Slavery, 22 Small Axe: A Caribbean Journal of Criticism 1–17 (2018).

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#crashcourse #history #slavery

Did you know that at a certain point on a moving wheel... there's no motion? I mean, kinda... it's all relative, right? Prepare to have your mind blown in this episode of Crash Course Physics where Shini delves into the world of rotational motion!

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Produced in collaboration with PBS Digital Studios: http://youtube.com/pbsdigitalstudios

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Sometimes the most intimidating part of making a movie is that little box of concentrated technology called "The Camera." But, FEAR NOT! In this episode of Crash Course Film Production, Lily Gladstone helps us dissect the basics of modern movie cameras so you can have an easier time getting started... hopefully!
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Produced in collaboration with PBS Digital Studios: http://youtube.com/pbsdigitalstudios
***

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Educational video for children to learn which are the most famous carnivorous dinosaurs. With the help of a friendly crocodile that travels back in time to the era of these animals, the kids will learn about the most famous and curious dinosaurs and their characteristics.
What was the velociraptor like?, What habitat did the plesiosaur live in?, What does the Spinosaurus look like today?, How did the Pteranodon move?, Why was the Tyrannosaurus Rex so ruthless?, What was the Stegosaurus like?, What made the Triceratops different?, What does the Parasaurolophus look like today?, How big was the Diplodocus?, How did the Ankylosaurus defend itself? How many toes did Linhenykus have?, What did the nose of Qianzhousaurus look like?, What did Kosmoceratops' head look like?, What did Amargasaurus defend itself with?, What animal did Suzhousaurus look like? Let kids discover the amazing world of dinosaurs.

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If you like our videos, download Smile and Learn now. You’ll discover thousands of activities for children aged 3 to 12 yeards, all designed by educators. We have hundreds of games, interactive stories and videos in five languages: English, Spanish, Portuguese, Italian, Turkish and French. Try a month for free and start the adventure!

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Educational video for children to learn what the brain is, which are its parts and how it works. The brain is in charge of coordinating all vital functions of our body and gives meaning to what is happening around us. It receives signals from our environment and sends messages to different parts of our body so that they would respond adequately. The brain is divided into three parts: the cerebellum, the encephalic trunk and the cerebral cortex. In this video we're going to look at each part's function with specific examples. The video also explains the division of the brain into two hemispheres: the right hemisphere which is the location of intuition or creativity and the left hemisphere, which controls tasks like calculating, reasoning or language.

This video belongs to a collection of videos about the human body and how it works. Excellent resource for elementary school education.

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We only upload our own content, designed by educators so that children smile and learn while watching a video.

All of our content reinforces educational values, encouraging the use of multiple intelligences and language learning.

If you like our videos, download Smile and Learn now. You’ll discover more than 5.000 activities for children aged 3 to 12 yeards, all designed by educators. We have 250 games and interactive stories and over 280 videos in five languages: English, Spanish, Portuguese, Italian and French. Try a month for free and start the adventure!

Educational video for children that talks about the fourth of the Sustainable Development Goals (SDGs): the goal of quality education. Education is the process by which people gain access to knowledge. This is what allows us to better understand our communities’ values and culture, build social skills, and get necessary training to perform different jobs. All these things make quality education extremely important for a fulfilling and independent life. That is why it is a basic right for children, adolescents and adults all over the world. This is also why it is the fourth sustainable development goal to ensure that this right is respected and that children, adolescents and adults have access to the education system. According to data from the United Nations, more than 260 million children in the world are not attending school, or rather, they cannot go to school. Sometimes this happens when children live far away from their schools and have to travel very long distances every day to go to school. Poverty is also a factor that limits access to education. Many children have to start working when they are very young in order to help their families economically, and this situation causes them to leave school before they finish their studies. Another reason that prevents access to the education system is the armed conflict or war situations that are occurring in some countries around the world.

This video is a very useful and interesting resource for children. It is perfect for teaching what the Sustainable Development Goals are and is an excellent video for primary education.

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If you like our videos, download Smile and Learn now. You’ll discover thousands of activities for children aged 3 to 12 years, all designed by educators. We have hundreds of games, interactive stories and videos in five languages: English, Spanish, Portuguese, Italian, Turkish and French. Try a month for free and start the adventure!

www.smileandlearn.com

Educational, Science video for kids. Find out everything about plants, photosynthesis, the Solar System, vertebrate and invertebrate animals, the respiratory and circulatory system and everything related with this subject. You will also learn lots of interesting facts while having fun.

This video compilation is part of a larger collection of Science videos for kids.Wonderful resource for Science class, in Primary school.Thanks for visiting us! If you want your children to smile and learn, subscribe! :D

We only upload our own content, designed by educators so that children smile and learn while watching a video.

All of our content reinforces educational values, encouraging the use of multiple intelligences and language learning.

If you like our videos, download “The Smart Library” now. You’ll discover more than 70 interactive games and stories for children designed by educators. The stories are based on VALUES like friendship, respect, and generosity, and our games cover all of the MULTIPLE INTELLIGENCES. All our content is in SPANISH, ENGLISH, FRENCH, ITALIAN and PORTUGUESE.

Educational video for children to learn about a typical day at school, plus tips and vocabulary related to school such as: class, teacher, books, alphabet, desk, computer, pencil, pencil case, ruler, clock, notebook, markers, eraser, scissors, chalk, trash can, exam, homework, playground, blackboard, dictionary, backpack, schedule, atlas, subjects. This is a perfect resource to work on routines and basic school concepts in early childhood education and special education.

Thanks for visiting us! If you want your children to smile and learn, subscribe! :D

We only upload our own content, designed by educators so that children smile and learn while watching a video.

All of our content reinforces educational values, encouraging the use of multiple intelligences and language learning.

If you like our videos, download Smile and Learn now. You’ll discover thousands of activities for children aged 3 to 12 yeards, all designed by educators. We have hundreds of games, interactive stories and videos in five languages: English, Spanish, Portuguese, Italian and French. Try a month for free and start the adventure!

This is a kids' video which teaches values like friendship or teamwork while enjoying this fantasy story. The Nutcracker is the ideal Christmas story, it beautifully reflects children’s enthusiasm and the true spirit of Christmas time. Find out everything you can achieve through teamwork, just like Clara and the Nutcracker. Look for a trusty friend to share your adventures with. Are you up for the challenge?

Thanks for visiting us! If you want your children to smile and learn, subscribe! :D

We only upload our own content, designed by educators so that children smile and learn while watching a video.

All of our content reinforces educational values, encouraging the use of multiple intelligences and language learning.

If you like our videos, download “The Smart Library” now. You’ll discover more than 70 interactive games and stories for children designed by educators. The stories are based on VALUES like friendship, respect, and generosity, and our games cover all of the MULTIPLE INTELLIGENCES. All our content is in SPANISH, ENGLISH, FRENCH, ITALIAN and PORTUGUESE.

The perfect tool to use in and out of school.

Download it today!

-Apple Store: https://itunes.apple.com/us/ap....p/smart-edutainment-

-Google Play: https://play.google.com/store/....apps/details?id=net.

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Educational video for children to learn sports vocabulary. In this compilation video, they will find out what these sports related words mean: tennis, swimming, basketball, football, cycling, athletics, rowing, rugby, skiing, scuba-diving, table tennis, badminton, baseball, hockey, paragliding, gymnastics, handball, horseback riding, sailing and volleyball.

Thanks for visiting us! If you want your children to smile and learn, subscribe! :D

We only upload our own content, designed by educators so that children smile and learn while watching a video.

All of our content reinforces educational values, encouraging the use of multiple intelligences and language learning.

If you like our videos, download Smile and Learn now. You’ll discover more than 5.000 activities for children aged 3 to 12 yeards, all designed by educators. We have 250 games and interactive stories and over 280 videos in five languages: English, Spanish, Portuguese, Italian and French. Try a month for free and start the adventure!

Kids educational video, to learn how to cook delicious recipes, like the tiramisu dessert or the watermelon shake. Ideal for family cooking at any time of the year.

This is a compilation video about dessert cooking, part of a larger video collection on Nutrition and Recipes, for kids to learn how to cook in a fun way. Wonderful resource for Primary School and Preschool.

Thanks for visiting us! If you want your children to smile and learn, subscribe! :D

We only upload our own content, designed by educators so that children smile and learn while watching a video.

All of our content reinforces educational values, encouraging the use of multiple intelligences and language learning.

If you like our videos, download “The Smart Library” now. You’ll discover more than 70 interactive games and stories for children designed by educators. The stories are based on VALUES like friendship, respect, and generosity, and our games cover all of the MULTIPLE INTELLIGENCES. All our content is in SPANISH, ENGLISH, FRENCH, ITALIAN and PORTUGUESE.

The perfect tool to use in and out of school.

Download it today!

-Apple Store: https://itunes.apple.com/us/ap....p/smart-edutainment-

-Google Play: https://play.google.com/store/....apps/details?id=net.

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Thank you for trusting us with your children's education!

Educational video for children to learn about what is a wildfire. They will also learn how it originates and how it affects us. A wildfire is a large fire that spreads out of control and it occurs in natural environments such as forests or grasslands. Wildfires can cause severe losses in the flora and fauna areas where they originate. They can be caused by natural causes, such as a lightning strike, or sadly, due to human action.

This video is a resource that compiles information about wildfires, it is ideal for natural science in elementary school.

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If you like our videos, download Smile and Learn now. You’ll discover thousands of activities for children aged 3 to 12 years, all designed by educators. We have hundreds of games, interactive stories and videos in five languages: English, Spanish, Portuguese, Italian, Turkish and French. Try a month for free and start the adventure!

www.smileandlearn.com

Are you in the mood to learn new things about the alphabet? Today we've got a compilation of the whole alphabet. It can help improve what you've learnt!

This video is part of a series focusing on the letters of the alphabet. It shows some words that start with the letters A, all the way to Z in order to learn their sounds. At the end of the video children can find a sing-along to practice!

Thanks for visiting us! If you want your children to smile and learn, subscribe! :D

We only upload our own content, designed by educators so that children smile and learn while watching a video.

All of our content reinforces educational values, encouraging the use of multiple intelligences and language learning.

If you like our videos, download “The Smart Library” now. You’ll discover more than 100 interactive games and stories for children designed by educators. The stories are based on VALUES like friendship, respect, and generosity, and our games cover all of the MULTIPLE INTELLIGENCES. All our content is in SPANISH, ENGLISH, FRENCH, ITALIAN and PORTUGUESE.

The perfect tool to use in and out of school.

Download it today!

-Apple Store: https://itunes.apple.com/us/ap....p/smart-edutainment-

-Google Play: https://play.google.com/store/....apps/details?id=net.

www.smileandlearn.com

Thank you for trusting us with your children's education!