Video hàng đầu

Pythagoras Theorem
Pythagoras Theorem Teacherflix 7 Lượt xem • 2 năm trước kia

The Pythagorean theorem is an easy to use relation in geometry among the three sides of a right triangle. It states that the area of the square whose side is the hypotenuse (the side opposite the right angle) is equal to the sum of the areas of the squares on the other two sides.

To support tecmath on Patreon:
https://www.patreon.com/tecmath

BTW for those interested - Pythagorean history is fascinating!
Pythagoreanism originated in the 6th century BC, based on the teachings and beliefs held by Pythagoras and his followers, the Pythagoreans. Pythagoras established the first Pythagorean community in Italy. These guys were into the divinity of numbers and were a fully blown religion!
Of all the stories of the Pythogeans - one on my favourite is the one Hippasus - a devoted follower.
Legend has it that he was the first person to prove the existence of an irrational number—he showed that the square root of two was an irrational, never-ending number. This was more than just a major discovery—it was open rebellion! Pythagoras had taught that all numbers could be expressed as ratios of integers, and Hippasus had proven his divine teacher wrong.According to the legend, Hippasus showed his proof to Pythagoras while they were on a boat. In response, Pythagoras grabbed Hippasus, wrestled him to the side of the boat, and held his head underwater until he stopped moving. Then Pythagoras threw the lifeless body overboard, turned to the others aboard, and warned them never to tell a soul what had happened.That story is probably not true. It seems to be a twisted version of a Pythagorean fable that said Hippasus was drowned by the gods as punishment for disclosing the secret of irrational numbers to the world.But that story still reveals something creepy about the Pythagorean cult. They spread this story, it’s believed, as a parable—a warning telling their followers that if they shared the cult’s secrets with the world, they could expect a watery grave. To donate to the tecmath channel: https://paypal.me/tecmath?locale.x=en_AU To donate to the tecmath channel: https://paypal.me/tecmath?locale.x=en_AU
To support tecmath on Patreon: https://www.patreon.com/tecmath
To buy tecmath mechandise: https://teespring.com/stores/tecmath-store

Dad and the Dinosaur - Children's Story - Father's Day Books Read Aloud
Dad and the Dinosaur - Children's Story - Father's Day Books Read Aloud Teacherflix 7 Lượt xem • 2 năm trước kia

Dad and the Dinosaur
by Gennifer Choldenko
Illustrated by Dan Santat
Read by Let's Read Stories

A heartwarming father-son story about bravery and facing fears.

Nicholas was afraid of the dark outside his door, the bushes where the giant bugs live, and the underside of manhole covers.

His dad was not afraid of anything.

Nicholas wants to be as brave as his dad, but he needs help. That’s why he needs a dinosaur. After all, dinosaurs like the dark, bugs are nothing to them, and they eat manhole covers for lunch (and everything under them for dinner).

With his toy dinosaur, Nicholas can scale tall walls, swim in deep water, even score a goal against the huge goalie everyone calls Gorilla. But when the dinosaur goes missing, everything is scary again.

Luckily, his dad knows that even the bravest people can get scared, and it’s okay to ask for help facing your fears. It’s just guy stuff.

A family classic in the making from the dream team of Newbery Honor-winner Gennifer Choldenko and Caldecott Medal-winner Dan Santat.

★ "[Choldenko's] knowing, understated storytelling and Santat’s warm, expressive spreads give full credence to the fears that weigh on kids, as well as the presences—both real and imagined—that can help alleviate them."—Publishers Weekly (starred review)
Click here to purchase Dad and the Dinosaur:
https://www.amazon.com/Dad-Din....osaur-Gennifer-Chold

Grumpy Cat The First Worst Christmas - Christmas Stories Read Aloud for Children by Kids
Grumpy Cat The First Worst Christmas - Christmas Stories Read Aloud for Children by Kids Teacherflix 7 Lượt xem • 2 năm trước kia

Grumpy Cat The First Worst Christmas - Christmas Stories Read Aloud for Children by Kids

Click here to purchase Grumpy Cat the First Worst Christmas:
https://www.amazon.com/Grumpy-....First-Worst-Christma

Grumpy Cat, the most famous cat in the world, stars in her very own Christmas-themed Big Golden Book!

Grumpy Cat has over 8 million Facebook followers, her own TV movie, a mobile game, and now . . . a Christmas-themed Big Golden Book! In the story of Grumpy Cat’s First Worst Christmas, Pokey makes every effort to get Grumpy Cat to join in the Christmas spirit! Pokey wants to build a snow-cat together, go sledding, decorate the Christmas tree, and bake cookies for Santa! But Grumpy Cat wants to live in her wonderland of NO. Join your favorite feline as she celebrates the most terrible time of the year! Grumpy Cat fans of all ages will get into the spirit with this Big Golden Book, featuring all-new full-color illustrations.

The Industrial Revolution: Crash Course European History #24
The Industrial Revolution: Crash Course European History #24 Teacherflix 7 Lượt xem • 2 năm trước kia

We've talked about a lot of revolutions in 19th Century Europe, and today we're moving on to a less warlike revolution, the Industrial Revolution. You'll learn about the development of steam power and mechanization, and the labor and social movements that this revolution engendered.

SOURCES

Hobsbawm, Eric. Studies in Archaic Forms of Social Movements in the 19th and 20th Centuries. New York: W. W. Norton, 1965.

Hunt, Lynn. et al. The Making of the West: Peoples and Cultures, 6th ed. Boston: Bedford St. Martin’s, 2019.

Kent, Susan Kingsley. A New History of Britain since 1688: Four Nations and an Empire. New York: Oxford University Press, 2017.

Riello, Giorgio. Cotton: The Fabric That Made the Modern World. Cambridge: Cambridge University Press, 2013.

Smith, Bonnie G. et al. World in the Making: A Global History. New York: Oxford University Press, 2019.


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, Indika Siriwardena, Avi Yashchin, Timothy J Kwist, Brian Thomas Gossett, Haixiang N/A Liu, Jonathan Zbikowski, Siobhan Sabino, Zach Van Stanley, Jennifer Killen, Nathan Catchings, Brandon Westmoreland, dorsey, 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, Tim Curwick, David Noe, Shawn Arnold, William McGraw, Andrei Krishkevich, Rachel Bright, Jirat, Ian Dundore
--

Want to find Crash Course elsewhere on the internet?
Facebook - http://www.facebook.com/YouTubeCrashCourse
Twitter - http://www.twitter.com/TheCrashCourse
Tumblr - http://thecrashcourse.tumblr.com
Support Crash Course on Patreon: http://patreon.com/crashcourse

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

#crashcourse #history #europeanhistory

The French Revolution: Crash Course European History #21
The French Revolution: Crash Course European History #21 Teacherflix 7 Lượt xem • 2 năm trước kia

In 1789, the French Monarchy's habit of supporting democratic popular revolutions in North America backfired. Today, we're talking about the French Revolution. Across the world, people were rising up to throw off monarchies, and Louis didn't see the writing on the wall until it was too late. Today we'll talk about how the French Revolution unfolded, and what (if anything) was really accomplished. You'll learn about stuff like the National Assembly, the Tennis Court Oath, the Declaration of the Rights of Man and the Citizen, the guillotine, Robespierre, and a bunch of other kind of unbelievable details.

Hatian Revolutions - CC World History:
https://youtu.be/5A_o-nU5s2U

Sources
Hunt, Lynn et al. Making of the West: Peoples and Cultures. 6th ed. Boston: Bedford St. Martin’s, 2019.


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, Indika Siriwardena, Avi Yashchin, Timothy J Kwist, Brian Thomas Gossett, Haixiang N/A Liu, Jonathan Zbikowski, Siobhan Sabino, Zach Van Stanley, Jennifer Killen, Nathan Catchings, Brandon Westmoreland, dorsey, 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
--

Want to find Crash Course elsewhere on the internet?
Facebook - http://www.facebook.com/YouTubeCrashCourse
Twitter - http://www.twitter.com/TheCrashCourse
Tumblr - http://thecrashcourse.tumblr.com
Support Crash Course on Patreon: http://patreon.com/crashcourse

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

#crashcourse #history #europeanhistory

The Civil War, Part I: Crash Course US History #20
The Civil War, Part I: Crash Course US History #20 Teacherflix 7 Lượt xem • 2 năm trước kia

In which John Green ACTUALLY teaches about the Civil War. In part one of our two-part look at the US Civil War, John looks into the causes of the war, and the motivations of the individuals who went to war. The overarching causes and the individual motivations were not always the same, you see. John also looks into why the North won, and whether that outcome was inevitable. The North's industrial and population advantages are examined, as are the problems of the Confederacy, including its need to build a nation at the same time it was fighting a war. As usual, John doesn't get much into the actual battle-by-battle breakdown. He does talk a little about the overarching strategy that won the war, and Grant's plan to just overwhelm the South with numbers. Grant took a lot of losses in the latter days of the war, but in the end, it did lead to the surrender of the South.

If you want to learn more about the Civil War, we recommend these books:
Battle Cry of Freedom by James McPherson:
https://bit.ly/3jAtBzo
The Civil War by Shelby Foote: https://bit.ly/38VXTKZ

Hey teachers and students - Check out CommonLit's free collection of reading passages and curriculum resources to learn more about the events of this episode. There were many causes of the American Civil War and events that led to disunion: https://www.commonlit.org/text....s/causes-of-the-amer
Once the war started, its outcome was determined by the different abilities and resources of the divided North and South: https://www.commonlit.org/text....s/a-nation-divided-n

Learn more about Black Americans in the Civil War in episode #18 of Crash Course Black American History: https://www.youtube.com/watch?v=_NgdnsjPFNE

Chapters:
Introduction 00:00
Basic Facts of the Civil War 1:21
Free and Slave States 1:46
Causes of the Civil War 2:15
Religion and the Civil War 3:19
Union Advantages in the Civil War 4:24
Confederate Advantages in the Civil War 5:11
Was the Union's Victory Inevitable? 5:53
Mystery Document 6:43
Ulysses S. Grant 7:39
Union Weaknesses in the Civil War 8:18
Turning Points in the Civil War 9:20
Lincoln's Reelection 10:47
Credits 11:28

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

The Black Legend, Native Americans, and Spaniards: Crash Course US History #1
The Black Legend, Native Americans, and Spaniards: Crash Course US History #1 Teacherflix 7 Lượt xem • 2 năm trước kia

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 00:00
Native North Americans 0:45
Were Native North Americans 'Primitive?' 1:08
Native North American Populations 1:52
Life in Pre-Columbian America 3:06
Class and Society in Native American Tribes 4:25
Spanish Colonization in North America 5:32
Mystery Document 7:58
The Problem with the Black Legend 9:31
Credits 10:46

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

The Quakers, the Dutch, and the Ladies: Crash Course US History #4
The Quakers, the Dutch, and the Ladies: Crash Course US History #4 Teacherflix 7 Lượt xem • 2 năm trước kia

In which John Green teaches you about some of the colonies that were not in Virginia or Massachusetts. Old New York was once New Amsterdam. Why they changed it, I can say; ENGLISH people just liked it better that way, and when the English took New Amsterdam in 1643, that's just what they did. Before the English got there though, the colony was full of Dutch people who treated women pretty fairly and allowed free Black people to hold jobs. John also discusses Penn's Woods, also known as Pennsylvania. Pennsylvania was (briefly) a haven of religious freedom, and William Penn dealt relatively fairly with the natives his colony displaced. Of course, as soon as Penn died, the colonist started abusing the natives immediately. We venture as far south as the Carolina colonies, where the slave labor economy was taking shape. John also takes on the idea of the classless society in America, and the beginning of the idea of the American dream. It turns out that in spite of the lofty dream that everyone had an equal shot in the new world, there were elites in the colonies. And these elites tended to be in charge. And then their kids tended to take over when they died. So yeah, not quite an egalitarian paradise. In addition to all this, we get into the Salem Witch Trials, the treatment of women in the colonies, and colonial economics. Oh yeah, one more thing, before you comment about how he says we're talking about the American Revolution next week, but the end screen says Seven Years War, consider that perhaps the Seven Years War laid the groundwork for the revolution to happen.

Chapters:
Introduction 00:00
New Amsterdam Becomes New York 0:55
Pennsylvania and the Quakers 2:05
South Carolina 3:37
Mystery Document 4:08
Bacon's Rebellion 5:14
The Dominion of New England and The Tolerance Act 6:17
The Salem Witch Trials 7:31
Colonial American Economics 8:05
Colonial American Society 9:11
Women's Roles in Colonial America 9:51
Credits 11:05

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

Introduction to the Solar System: Crash Course Astronomy #9
Introduction to the Solar System: Crash Course Astronomy #9 Teacherflix 7 Lượt xem • 2 năm trước kia

In today's Crash Course Astronomy, Phil takes a look at the explosive history of our cosmic backyard. We explore how we went from a giant ball of gas to the system of planets and other celestial objects we have today.

This episode is sponsored by Squarespace:
http://www.squarespace.com/crashcourse

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

--
Chapters:
Introduction 00:00
Geocentrism vs Heliocentrism 0:51
Makeup of the Solar System 2:38
Is Pluto a Planet? 3:14
Our Solar System 4:24
How Our Solar System Formed 5:36
Planet Formation Depends on Distance to Sun 7:14
Review 8:57

--

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

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

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

--

PHOTO/VIDEO CREDITS
Sun: http://www.nasa.gov/sites/defa....ult/files/706436main [credit: NASA/ESA]
Jupiter: http://www.jpl.nasa.gov/images..../hubble/20140515/jup [credit: NASA/ESA]
Geocentric celestial spheres; Peter Apian's Cosmographia (Antwerp, 1539): http://en.wikipedia.org/wiki/C....elestial_spheres#med
Ganymede: http://en.wikipedia.org/wiki/F....ile:Noaa_ganymede.jp
Mercury: http://messenger.jhuapl.edu/ga....llery/sciencePhotos/ [credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington]
Understanding Solar System Dynamics: Orbits and Kepler's Laws (2008): https://archive.org/details/OrbitsAndKeplersLaws
Mercury: http://apod.nasa.gov/apod/ap080116.html
Venus: http://www.msss.com/all_projects/magellan.php
Earth: http://earthobservatory.nasa.g....ov/IOTD/view.php?id=
Mars: http://nssdc.gsfc.nasa.gov/pho....to_gallery/photogall
Jupiter: http://www.nasa.gov/mission_pa....ges/cassini/multimed
Saturn: http://www.slate.com/content/d....am/slate/blogs/bad_a [credit: Photo by NASA/JPL/Space Science Institute/Gordan Ugarkovic]
Uranus: http://hubblesite.org/newscent....er/archive/releases/
Neptune: http://www.slate.com/blogs/bad...._astronomy/2014/05/1
http://www.nasa.gov/sites/defa....ult/files/hs-2014-29 [credit: JHUAPL/SwRI/Dan Durda]
Bennu’s Journey: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=20220&button=recent
http://svs.gsfc.nasa.gov/cgi-b....in/details.cgi?aid=1
Artist's impression of a protoplanetary disk: http://en.wikipedia.org/wiki/P....rotoplanetary_disk#m
Rocky Ring of Debris Around Vega: http://www.nasa.gov/mission_pa....ges/spitzer/multimed [image credit: NASA/JPL-Caltech]
Proplyds in the Orion Nebula: http://www.esa.int/Our_Activit....ies/Space_Science/Bo

The Creation of Chemistry - The Fundamental Laws: Crash Course Chemistry #3
The Creation of Chemistry - The Fundamental Laws: Crash Course Chemistry #3 Teacherflix 7 Lượt xem • 2 năm trước kia

Today's Crash Course Chemistry takes a historical perspective on the creation of the science, which didn't really exist until a super-smart, super-wealthy Frenchman put the puzzle pieces together - Hank tells the story of how we went from alchemists to chemists, who understood the law of conservation of mass as proposed by a decapitated aristocrat, and explains how we came to have a greater understanding of how chemical compounds work and eventually a complete understanding of what atoms and molecules are.

Watch this video in Spanish on our Crash Course en Español channel here:
https://youtu.be/HxDjcseTj6s

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

Table of Contents
Alchemists to Chemists 01:07
Law of Conservation of Mass 03:25
Decapitated Aristocrat 04:11
Chemical Compounds 05:44
Atoms and Molecules 06:07:1

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

Karl Popper, Science, & Pseudoscience: Crash Course Philosophy #8
Karl Popper, Science, & Pseudoscience: Crash Course Philosophy #8 Teacherflix 7 Lượt xem • 2 năm trước kia

The early 1900s was an amazing time for Western science, as Albert Einstein was developing his theories of relativity and psychology was born, as Sigmund Freud and psychoanalysis took over the scientific mainstream. Karl Popper observed these developments firsthand and came to draw a distinction between what he referred to as science and pseudoscience, which might best be summarized as science disconfirms, while pseudoscience confirms. While the way we describe these disciplines has changed in the intervening years, Popper’s ideas speak to the heart of how we arrive at knowledge.
--

Wanted: Santa Clause by Kevin Dooley
https://www.flickr.com/photos/....pagedooley/312444309 licensed under CC BY 2.0: https://creativecommons.org/licenses/by/2.0/
Rudolph the Red-Nosed Reindeer copyright Rankin/Bass Productions & DreamWorks Classics
Other images and video via VideoBlocks or Wikimedia Commons, licensed under Creative Commons by 4.0: https://creativecommons.org/licenses/by/4.0/

--

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

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

--

Want to find Crash Course elsewhere on the internet?
Facebook - http://www.facebook.com/YouTubeCrashC...
Twitter - http://www.twitter.com/TheCrashCourse
Tumblr - http://thecrashcourse.tumblr.com
Support CrashCourse on Patreon: http://www.patreon.com/crashcourse

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

The Market Revolution: Crash Course US History #12
The Market Revolution: Crash Course US History #12 Teacherflix 7 Lượt xem • 2 năm trước kia

In which John Green teaches you about the Market Revolution. In the first half of the 19th century, the way people lived and worked in the United States changed drastically. At play was the classic (if anything in a 30-year-old nation can be called classic) American struggle between the Jeffersonian ideal of individuals sustaining themselves on small farms vs. the Hamiltonian vision of an economy based on manufacturing and trade. I'll give you one guess who won. Too late! It was Hamilton, which is why if you live in the United States, you probably live in a city and are unlikely to be a farmer. Please resist the urge to comment about this if you live in the country and/or are a farmer. Your anecdotal experience doesn't change the fact that most people live in cities. In the early 19th century, new technologies in transportation and communication helped remake the economic system of the country. Railroads and telegraphs changed the way people moved goods and information around. The long and short of it is, the Market Revolution meant that people now went somewhere to work rather than working at home. Often, that somewhere was a factory where they worked for an hourly wage rather than getting paid for the volume of goods they manufactured. This shift in the way people work has repercussions in our daily lives right down to today. Watch as John teaches you how the Market Revolution sowed the seeds of change in the way Americans thought about the roles of women, slavery, and labor rights. Also, check out high school John wearing his Academic Decathalon medals.

Hey teachers and students - Check out CommonLit's free collection of reading passages and curriculum resources to learn more about the events of this episode. As America invested in its market economy, certain transcendentalists resisted the rise of production and consumerism over individual freedoms, including Henry David Thoreau in his book Walden:
https://www.commonlit.org/text....s/excerpt-from-walde
Ralph Waldo Emerson promoted transcendental values as well in his essay “Self-Reliance”: https://www.commonlit.org/text....s/excerpt-from-self-

Chapters:
Introduction: The Market Revolution 00:00
The Era of Good Feelings 1:00
New technology in transportation 1:43
Steamboats and canals 2:45
Railroads & telegraphs 3:35
Factories & interchangeable parts 4:02
The rise of modern banking 4:51
Encouraging Competition 5:37
Work & life during the Market Revolution 6:29
Westward expansion & "Manifest Destiny" 8:32
Mystery Document 10:09
Transcendentalists 11:28
Wealth disparities after the Market Revolution 11:53
Credits 13:33

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

Showing 193 out of 194