In which John Green teaches you about the poetry of Langston Hughes. Langston Hughes was a poet and playwright in the first half of the 20th century, and he was involved in the Harlem Renaissance, which was a cultural movement among African Americans of the time that produced all kinds of great works in literature, poetry, painting, sculpture, music, and other areas. The Harlem Renaissance mainly happened in Harlem, the traditionally black neighborhood in upper Manhattan in New York City. Langston Hughes was primarily known as a poet, but he was involved deeply in the movement itself as well. John will teach you a bit about Hughes's background, and he'll examine a few of his best-known poems.

Learn more about Langston Hughes and the Harlem Renaissance in Episode #26 of Crash Course Black American History: https://www.youtube.com/watch?v=vKaegbtcE00

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Population ecology is the study of groups within a species that interact mostly with each other, and it examines how they live together in one geographic area to understand why these populations are different in one time and place than they are in another. How is that in any way useful to anyone ever? Hank uses the example of the West Nile virus outbreak in Texas to show you in this episode of Crash Course: Ecology.

Table of Contents
1) Density & Dispersion 02:03
2) Population Growth 03:07
3) Limiting Factors 03:45
a) Density Dependent 06:16
b) Density Independent 07:11
4) Exponential & Logistical Growth 08:04
5) How to Calculate Growth Rate 09:33

References:
http://www.latimes.com/news/na....tion/nationnow/la-na
http://www.dshs.state.tx.us/id....cu/disease/arboviral
http://en.wikipedia.org/wiki/Mosquito
http://www.nature.com/scitable..../knowledge/library/p
Campbell Biology 9th ed.

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Today we’re going to talk about climate change which is when there is a change in the average weather patterns in a region over a long period of time - these changes can be natural or human-caused. We’ll discuss the main driving forces of climate change in the past and show you how what’s happening now is unlike anything in the past. Global warming, or when there is an increase in the average surface temperature of the planet, has been well-documented since the Industrial Revolution, and scientists have concluded that there is a 95% probability that human activities like burning fossil fuels, industrialization, modern agriculture, and deforestation have caused most of this most recent warming. And while individual actions do matter in helping to curb the disastrous implications of a warming planet, it’s also up to us to hold corporations and governments responsible for the policies and the large-scale emissions that play a disproportionate role in impacting our atmosphere and climate.

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#CrashCourse #Geography #Climate

Just like many great duos throughout history, Bulgaria and Germany have a fascinating (though uneven) relationship. In today’s episode, we’re going to take a closer look at the impact of politics on economies as we trace this history of Bulgaria and Germany following World War II, and examine the ways capitalism, and communism, impacted their economic strength today.

SOURCES

General
Getis, Bjelland, and Getis. Introduction to Geography, 15 ed. McGraw-Hill Education. 2017. ISBN: 978-1-259-57000-1

Gregory, Derek, Ron Johnston, Geraldine Pratt, Michael Watts, and Sarah Whatmore, eds. 2009. The Dictionary of Human Geography. 5th ed. Willey-Blackwell. ISBN: 978-1-4051-3288-6

For a free and open source option for Intro to Human Geography, see: https://humangeography.pressbooks.com/

For a free and open source option for World Regional Geography, see: https://worldgeography.pressbo....oks.com/front-matter

Cracking the AP Human Geography Exam: 2020 edition. The Princeton Review.

Sofia and Bulgaria General History
https://en.wikipedia.org/wiki/Sofia
https://www.cia.gov/the-world-....factbook/countries/b

Germany
https://vividmaps.com/germany-....is-still-divided-by-
https://www.britannica.com/pla....ce/Germany/The-East-
https://www.arcgis.com/apps/Ca....scade/index.html?app
https://www.pewresearch.org/fa....ct-tank/2019/11/06/e
https://www.bmwi.de/Redaktion/EN/Publikationen/jahresbericht-zum-stand-der-deutschen-einheit-2018.pdf?__blob=publicationFile&v=3

Bulgaria Economy
https://etd.ohiolink.edu/apexprod/rws_olink/r/1501/10?clear=10&p10_accession_num=osu1141408829
https://www.cia.gov/the-world-....factbook/countries/b#economy
https://www.worldbank.org/en/c....ountry/bulgaria/over
https://open.lib.umn.edu/world....geography/chapter/2-
https://www.imf.org/en/Publica....tions/SPROLLS/world-
https://www.imf.org/en/Countries/BGR
https://www.worldstopexports.c....om/bulgarias-top-15-
https://oec.world/en/profile/b....ilateral-country/rou
https://www.bbc.com/news/world-europe-17202996
http://news.bbc.co.uk/2/hi/europe/4001113.stm
http://news.bbc.co.uk/1/hi/world/europe/327199.stm

German Bulgaria relations
https://oec.world/en/profile/b....ilateral-country/deu
https://www.trademap.org/Count....ry_SelProductCountry
https://en.wikipedia.org/wiki/....Bulgaria%E2%80%93Ger

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Today on Crash Course Economics, Adriene and Jacob talk about the 2008 financial crisis and the US Goverment's response to the troubles. So, all this starts with home mortgages, and the use of mortgages as an investment instrument. For years, it seemed like the US housing market would go up and up. Like a bubble or something. It turns out it was a bubble. But not the good kind. And the government response was...interesting. Anyway, why are you reading this? Watch the video!

More Financial Crisis Resources:

Financial Crisis Inquiry Report: http://www.gpo.gov/fdsys/pkg/G....PO-FCIC/pdf/GPO-FCIC

TAL: Giant Pool of Money: http://www.thisamericanlife.or....g/radio-archives/epi

Timeline of the crisis: https://www.stlouisfed.org/fin....ancial-crisis/full-t

http://www.economist.com/news/....schoolsbrief/2158453

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We’ve talked about how broad a concept “the media” really is – and given that, it can be hard to keep track of all the different forces that constitute “the media.” It can be tough, but it’s not impossible. Today we’re talking about how all those big players fit together and why all those mergers and acquisitions matter to being a media literate citizen.

***

Resources:
NEW ERA FOR THE TELEPHONE: OWNERSHIP REPLACING RENTAL https://www.nytimes.com/1982/1....2/16/business/new-er

AT&T BREAKUP II : Highlights in the History of a Telecommunications Giant http://articles.latimes.com/19....95-09-21/business/fi

BELL SYSTEM BREAKUP OPENS ERA OF GREAT EXPECTATIONS AND GREAT CONCERN https://www.nytimes.com/1984/0....1/01/us/bell-system-

The Federal Communications Commission and the Bell System: Abdication of Regulatory Responsibility https://www.repository.law.indiana.edu/cgi/viewcontent.cgi?referer=&httpsredir=1&article=2509&context=ilj

The Knight Foundation: How Youth Navigate the News Landscape https://knightfoundation.org/r....eports/how-youth-nav

Experimental evidence of massive-scale emotional contagion through social networks http://www.pnas.org/content/111/24/8788.full

Facebook and Twitter are being used to manipulate public opinion https://www.theguardian.com/te....chnology/2017/jun/19

***

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Hank introduces us to that wondrous molecule deoxyribonucleic acid - also known as DNA - and explains how it replicates itself in our cells.

References:
http://www.nature.com/nature/dna50/watsoncrick.pdf
http://publications.nigms.nih.....gov/thenewgenetics/c
http://rst.gsfc.nasa.gov/Sect20/A12.html
http://www.nature.com/scitable..../topicpage/discovery
http://www.uic.edu/classes/phy....s/phys461/phys450/AN
http://www.buzzle.com/articles..../dna-replication-ste
http://www.dnareplication.info..../stepsofdnareplicati
http://salamandercandy.wordpre....ss.com/2007/02/05/ho
http://www.sdsc.edu/ScienceWomen/franklin.html
http://www.fmi.ch/members/mari....lyn.vaccaro/ewww/dna
http://www.strangescience.net/rfranklin.htm

1:41 link to Biological Molecules http://www.youtube.com/watch?v=H8WJ2KENlK0

Table of Contents:
1) Nucleic Acids 1:30
2) DNA
-A) Polymers 1:53
-B) Three Ingredients 2:12
-C) Base Pairs 3:45
-D) Base Sequences 4:13
3) Pop Quiz 5:07
4) RNA 5:36
-A) Three Differences from DNA 5:43
5) Biolography 6:16
6) Replication 8:49
-A) Helicase and Unzipping 9:22
-B) Leading Strand 9:38
-C) DNA Polymerase 10:08
-D) RNA Primase 10:24
-E) Lagging Strand 10:46
-F) Okazaki Fragments 11:07
-F) DNA Ligase 11:47

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Hank teaches us why water is one of the most fascinating and important substances in the universe.

Review:
Re-watch = 00:00
Introduction = 00:42
Molecular structure & hydrogen bonds = 01:38
Cohesion & surface tension = 02:46
Adhesion = 03:31
Hydrophilic substances = 04:42
Hydrophobic substances = 05:14
Henry Cavendish = 05:49
Ice Density = 07:45
Heat Capacity = 09:10

Citations:
http://www.extension.umn.edu/d....istribution/youthdev
http://www.uni.edu/~iowawet/H2OProperties.html
http://www.hometrainingtools.c....om/properties-water-
http://science.howstuffworks.c....om/environmental/ear
http://www.robinsonlibrary.com..../science/chemistry/b
http://chemistry.mtu.edu/~pcha....rles/SCIHISTORY/Henr
http://www.nndb.com/people/030/000083778/
http://www.notablebiographies.....com/Ca-Ch/Cavendish-

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Organic reactions are kind of like carefully choreographed fight scenes, and nucleophilic attack is a key move. This episode of Crash Course Organic Chemistry is all about nucleophiles and electrophiles, or what happens at those molecular hot spots we’ve been talking about. We’ll also learn about what IR spectra can tell us about reactions, and how cyanide is more than just a poison from mystery stories. Let’s get to it organophiles!

Series Sources:
Brown, W. H., Iverson, B. L., Ansyln, E. V., Foote, C., Organic Chemistry; 8th ed.; Cengage Learning, Boston, 2018.
Bruice, P. Y., Organic Chemistry, 7th ed.; Pearson Education, Inc., United States, 2014.
Clayden, J., Greeves, N., Warren., S., Organic Chemistry, 2nd ed.; Oxford University Press, New York, 2012.
Jones Jr., M.; Fleming, S. A., Organic Chemistry, 5th ed.; W. W. Norton & Company, New York, 2014.
Klein., D., Organic Chemistry; 1st ed.; John Wiley & Sons, United States, 2012.
Louden M., Organic Chemistry; 5th ed.; Roberts and Company Publishers, Colorado, 2009.
McMurry, J., Organic Chemistry, 9th ed.; Cengage Learning, Boston, 2016.
Smith, J. G., Organic chemistry; 6th ed.; McGraw-Hill Education, New York, 2020.
Wade., L. G., Organic Chemistry; 8th ed.; Pearson Education, Inc., United States, 2013.

***
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This week Jacob and Adriene teach you about marginal analysis, which you're using RIGHT NOW! The video is coming from inside the house! Or something. You'll learn how marginal analysis guides the decision making if cities, nations, companies, and amusement park enthusiasts. We'll also look at the idea of elasticity, and what people are willing to pay for certain stuff based on the supply. Why is a Van Gogh worth more than an OBEY poster? (hint: it's because they're still cranking out the OBEY posters, and Vincent is dead) All this and more on Crash Course Economics!

***

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It's time to heat things up! LITERALLY! It's time for Hank to talk about the history of Thermodynamics!!! It's messy and there are a lot of people who came up with some ideas that worked and other that didn't and then some ideas that should have come first actually were figured out second.

***

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In which John Green explores F. Scott Fitzgerald's novel of the Jazz Age, The Great Gatsby. John introduces you to Nick Carraway, Jay Gatsby, Daisy and Tom Buchanan, and the other characters in the novel, and tries to look beyond the surface story to figure out what this thing is ABOUT. Set in the 1920s against a conflicted backdrop of prohibition and excess, The Great Gatsby takes a close look at the American Dream as it existed in Fitzgerald's time. It turns out, it had a lot to do with money and status, and it still does today. John will cover the rich symbolism of the novel, from the distant green light to the pale gold of wealth and decay. Also, Paris Hilton drops by.

Turn on the captions. You'll like it.

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So, during times of inflation or deflation, why doesn't the government just set prices? It sounds reasonable, but price ceilings or floors just don't work. Adriene and Jacob explain why. Subsidies, however, are a little different, and sometimes they even work. We'll also explain that. Today you'll learn about stuff like price controls, deadweight loss, subsidies, and efficiency.

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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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In which John Green teaches you about one of the least funny subjects in history: slavery. John investigates when and where slavery originated, how it changed over the centuries, and how Europeans and colonists in the Americas arrived at the idea that people could own other people based on skin color.

Slavery has existed as long as humans have had civilization, but the Atlantic Slave Trade was the height, or depth, of dehumanizing, brutal, chattel slavery. American slavery ended less than 150 years ago. In some parts of the world, it is still going on. So how do we reconcile that with modern life? In a desperate attempt at comic relief, Boba Fett makes an appearance.

Learn more about the Transatlantic Slave Trade in Episode #1 of Crash Course Black American History here: https://youtu.be/S72vvfBTQws

Chapters:
Introduction 00:00
The Atlantic Slave Trade 0:30
The History of European Slave Trade 1:12
How Africans Became Enslaved 1:54
Living Conditions of Enslaved People 2:55
An Open Letter to the Word 'Slave' 5:41
What is the Definition of Slavery? 6:45
Other Models of Slavery: Greek, Roman, Judeo-Christian, and Muslim 7:26
Credits 10:35

Resources:
Inhuman Bondage by David Brion Davis: https://bit.ly/3vdSdTX
Up From Slavery by Booker T Washington: https://bit.ly/3JJlxH4

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Today Phil explores the world of tides! What is the relationship between tides and gravity? How do planets and their moons become tidally locked? What would happen if you were 300km tall? Important questions.

Check out the Crash Course Astronomy solar system poster here: http://store.dftba.com/product....s/crashcourse-astron

--
Chapters:
Introduction 00:00
Gravity Over Distance 0:44
Tidal Force Parameters 1:35
Battle of the Bulges 2:55
High and Low Tides 3:47
Push & Pull 4:51
Tidal Lock 6:07
Sun Tides 6:58
Review 8:51
--

PBS Digital Studios: http://youtube.com/pbsdigitalstudios

Follow Phil on Twitter: https://twitter.com/badastronomer

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PHOTO/VIDEO CREDITS
Photo & video credit: "NASA's Scientific Visualization Studio"
http://svs.gsfc.nasa.gov/cgi-b....in/details.cgi?aid=4 Photo credit: "NASA's Scientific Visualization Studio"
https://www.flickr.com/photos/....gsfc/8556665115/in/p
http://svs.gsfc.nasa.gov/cgi-b....in/details.cgi?aid=1
The Hopewell Rocks - https://www.youtube.com/watch?v=EnDJ6_XpGfo

I'm sure you've heard of Pavlov's Bell, but what was Ivan Pavlov up to, exactly? And how are our brains trained? And what is a "Skinner Box"? All those questions and more are answered in today's Crash Course Psychology, in which Hank talks about some of the aspects of learning.

Want more videos about psychology? Check out our sister channel SciShow Psych at https://www.youtube.com/scishowpsych!
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Chapters:
Introduction: Ivan Pavlov 00:00
Associative Learning 1:33
Classical Conditioning 2:47
Behaviorist Theory 4:22
Watson's Experiments 4:46
Operant Conditioning 5:42
Positive & Negative Reinforcement 7:18
Primary Reinforcers & Conditioned Reinforcers 8:54
Reinforcement Scheduling 9:32
Review & Credits 11:00
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Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse

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Facebook - http://www.facebook.com/YouTubeCrashCourse
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CC Kids: http://www.youtube.com/crashcoursekids

You may think you know all about hypnosis from the movies. Zoolander, The Manchurian Candidate, etc... but there's a whole lot more going on. In this episode of Crash Course Psychology, Hank tells us about some of the many altered states of consciousness, including hypnosis.

Want more videos about psychology? Check out our sister channel SciShow Psych at https://www.youtube.com/scishowpsych

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Chapters:
Introduction: Hypnosis & Altered States of Consciousness 00:00
Facts & Fallacies About Hypnosis 2:00
How does hypnosis work? 3:05
Drug Tolerance & Neuroadaptation 4:49
Psychoactive Drugs 5:51
Depressants 6:28
Stimulants 7:35
Hallucinogens/Psychedelics 9:04
Non-Drug Induced Hallucinations 9:33
Review & Credits 10:32
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Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse

Want to find Crash Course elsewhere on the internet?
Facebook - http://www.facebook.com/YouTubeCrashCourse
Twitter - http://www.twitter.com/TheCrashCourse
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CC Kids: http://www.youtube.com/crashcoursekids

You've probably heard the word "Entrepreneur" thrown around a lot in business. It conjures images of Elon Musk, Bill Gates, or Oprah Winfrey. But, it goes way beyond that. In this episode of Crash Course Business: Entrepreneurship, Anna helps us to figure out who Entrepreneurs are, and what that title actually means.


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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:

Eric Prestemon, Sam Buck, Mark Brouwer, Timothy J Kwist, Brian Thomas Gossett, Haxiang N/A Liu, Jonathan Zbikowski, Siobhan Sabino, Zach Van Stanley, Bob Doye, Jennifer Killen, Nathan Catchings, Brandon Westmoreland, dorsey, Indika Siriwardena, Kenneth F Penttinen, Trevin Beattie, Erika & Alexa Saur, Justin Zingsheim, Jessica Wode, Tom Trval, Jason Saslow, Nathan Taylor, Khaled El Shalakany, SR Foxley, Sam Ferguson, Yasenia Cruz, Eric Koslow, Caleb Weeks, Tim Curwick, David Noe, Shawn Arnold, William McGraw, Andrei Krishkevich, Rachel Bright, Jirat, Ian Dundore
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Want to find Crash Course elsewhere on the internet?
Facebook - http://www.facebook.com/YouTubeCrashCourse
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CC Kids: http://www.youtube.com/crashcoursekids

Hank describes how cells regulate their contents and communicate with one another via mechanisms within the cell membrane.

"Concert" music used with permission from Chameleon Circuit.
This video uses sounds from Freesound.org

Table of Contents time codes:
1) Passive Transport - 1:17
2) Diffusion - 1:25
3) Osmosis - 2:12
4) Channel Proteins- 4:37
5) Active Transport - 4:58
6) ATP - 5:37
7) Transport Proteins - 6:19
8) Biolography - 6:37
9) Vesicular Transport - 9:02
10) Exocytosis - 9:21
11) Endocytosis - 9:50
12) Phagocytosis - 9:57
13) Pinocytosis - 10:29
14) Receptor-Mediated Endocytosis - 10:48

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

Want to find Crash Course elsewhere on the internet?
Facebook - http://www.facebook.com/YouTubeCrashCourse
Twitter - http://www.twitter.com/TheCrashCourse
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CC Kids: http://www.youtube.com/crashcoursekids

Feeling motivated? Even if you are, do you know why? The story of Aaron Ralston can tell us a lot about motivation. In this episode of Crash Course Psychology, Hank tells us Ralston's story, as well as 4 theories of motivation and some evolutionary perspectives on motivation.

Want more videos about psychology? Check out our sister channel SciShow Psych at https://www.youtube.com/scishowpsych!

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Chapters:
Introduction: Motivation 00:00
What is Motivation? 1:08
Evolutionary Perspective: Instincts 1:29
Drive-Reduction Theory: Homeostasis & Incentives 2:37
Optimal Arousal 3:39
Maslow's Hierarchy of Needs 4:49
How Sex Motivates Us 5:29
How Hunger Motivates Us 6:32
Effects of Hunger & Starvation 7:59
How Social Belonging Motivates Us 9:33
Review & Credits 10:34
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Crash Course is on Patreon! You can support us directly by signing up at http://www.patreon.com/crashcourse

Want to find Crash Course elsewhere on the internet?
Facebook - http://www.facebook.com/YouTubeCrashCourse
Twitter - http://www.twitter.com/TheCrashCourse
Instagram - https://www.instagram.com/thecrashcourse/

CC Kids: http://www.youtube.com/crashcoursekids