Computers are pretty great, and we use them for different language tasks every day. But teaching computers to understand language is surprisingly difficult! In this episode of Crash Course Linguistics, we’ll learn about programming computers to process human language, which is called computational linguistics, or natural language processing. We’ll look at the types of language tasks computers can and can’t do, how natural language processing works, as well as the different types of biases that exist in machine learning.

This week we’re exploring a field of engineering that is essential to how you’re watching this video: computers and computer engineering. We’ll explain differences between hardware and software, how engineers are working on making computers smaller and more energy efficient, and how computer aided processes such as CAD and CAM make it easier for engineers to design and manufacture parts needed in machines and products.

Today we start a three episode arc on the rise of a global telecommunications network that changed the world forever. We’re going to begin with computer networks, and how they grew from small groups of connected computers on LAN networks to eventually larger worldwide networks like the ARPANET and even the Internet we know today. We'll also discuss how many technologies like Ethernet, MAC addresses, IP Addresses, packet switching, network switches, and TCP/IP were implemented to new problems as our computers became ever-increasingly connected. Next week we’ll talk about the Internet, and the week after the World Wide Web!

Today we’re going to talk about how computers see. We’ve long known that our digital cameras and smartphones can take incredibly detailed images, but taking pictures is not quite the same thing. For the past half-century, computer scientists have been working to help our computing devices understand the imagery they capture, leading to advancements everywhere, from tracking hands and whole bodies, biometrics to unlock our phones, and eventually giving autonomous cars the ability to understand their surroundings.

Computers and computing have changed a lot over the History of Science but ESPECIALLY over the last 100 years. In this episode of Crash Course History of Science, we have a look at that history around World War Two and how that conflict forced changes in computing.

Today we’re going to talk about confidence intervals. Confidence intervals allow us to quantify our uncertainty, by allowing us to define a range of values for our predictions and assigning a likelihood that something falls within that range. And confidence intervals come up a lot like when you get delivery windows for packages, during elections when pollsters cite margin of errors, and we use them instinctively in everyday decisions. But confidence intervals also demonstrate the tradeoff of accuracy for precision - the greater our confidence, usually the less useful our range.

*This video was published in 2015 and therefore does not reflect recent historical events, nor context about the ongoing conflict between Israel and Palestine.*

In which John Green teaches you about the conflict in Israel and Palestine. This conflict is often cast as a long-term beef going back thousands of years, rooted in a clash between religions. Well, that's not quite true. What is true is that the conflict is immensely complicated, and just about everyone in the world has an opinion about it. John is going to try to get the facts across in under 13 minutes.

In which John Green teaches you about the Democratic Republic of the Congo, which used to be Zaire, which used to be The Belgian Congo, which used to be the Congo Free State, which used to be the region surrounding the Congo River Basin in central Africa. So the history of this place is a little convoluted. The history of Congo is central to the history of central Africa, and the Congo Wars embroiled neighboring countries like Uganda and Rwanda. John will talk you through the history of Congo and the region.

This week Craig Benzine clears up the role of committees in Congress. We’ll talk about standing committees, joint committees, conference committees, and caucuses (and not the candidate-choosing kinds) as well as the staff agencies that help advise these committees and congresspeople. As most bills never even make it to the house and senate floors for a vote, the role of committees, and their respective chairpersons as gatekeepers is pretty important. There’s a lot to demystify here as the legislative process can seem pretty arcane at times, but the model, at least in theory, helps Congress run more efficiently.

This week Craig breaks out the crystal ball to try and figure out why our congresspeople do the things that they do. We’ll talk about the three motivating factors of congressional decisions - constituency, interest groups, and political parties - and we’ll break down how each of these factors motivates certain actions like casework, public opinion polls, and logrolling. Craig will even weigh in on which of these factors probably contributes most significantly to the actions and decisions of our congresspersons and he'll do it without even a touch of cynicism!

Chapters:
Introduction
How constituents & public opinion influence lawmakers
How interest groups influence lawmakers
How political parties influence lawmakers
Presidential power & political parties
Other influences on congressional decisions
Credits

In which Craig Benzine teaches you about delegation and informal powers. What are all these federal agencies about? Well, the President has a lot of stuff to do as the chief executive, and as much as Americans like to talk about personal responsibility, the President can't really do all this stuff alone. Because it's a huge job! Same deal with Congress. So, they delegate authority. This is where all the government agencies and stuff come from. Congress creates them to actually get around to enforcing laws. You'll learn about stuff like OSHA, the FDA, and maybe even the FCC. Although you hear an occasional complaint about bureaucracies and such, the business of government wouldn't get done without agencies and delegation.

Chapters:
Introduction: Delegation
What is delegation?
How Congress limits an agency's discretion
Why Congress delegates power
Congressionally delegated powers: key takeaways
Credits

This week Craig Benzine talks about the importance of elections in the strongest branch of the U.S. Government: Congress. He'll talk about the frequency of elections in the Senate and House, the typical characteristics of a candidate, and the motivating factors our congresspeople follow to get re-elected.

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.

The end of the Napoleonic Wars left the great powers of Europe shaken. Judging from the destruction that had been wrought across the continent, it seemed to the powers that be that the Enlightenment had liberated the people, and led to disaster. So, everybody got together in Vienna to have a Congress, and to try to put Europe "right" again. By "right" I mean they wanted to go back to the old days of kings, queens, and nobles running the show. But this new yearning for the past pervaded the continent. Roomanticism arose at the same time, looking back at (imagined) golden age of Medieval Times. Today we'll talk about the Congress of Vienna, The Holy Alliance, and the Romantic movement across the arts.

Carrots get their orange-y color from, you guessed it, an organic chemical. This chemical, called beta carotene, gets its pigment from its conjugated electron system. We’ve talked some already about conjugation, but in this episode of Crash Course Organic Chemistry we’ll go even deeper and look at how conjugation stabilizes molecules and how p orbitals can overlap to form pi molecular orbitals of different energy levels. Plus we’ll learn what UV spectroscopy can show us about conjugated molecules.

What exactly is consciousness? Well... that's kind of a gray area. In this episode of Crash Course Psychology, Hank gives you the basic ideas of what consciousness is, how our attention works, and why we shouldn't text and drive... ever... no, really, NEVER!

Chapters:
Introduction: What is Consciousness?
States of Consciousness
Cognitive Neuroscience & Neuroimaging
Dual Processing
Selective Attention
Inattentional Blindness
How Magicians Use Psychology
Review & Credits
Credits

Some scientists believe we are in the middle of Earth’s sixth mass extinction: a big, precarious game of Jenga that involves every ecosystem on the planet. In this episode of Crash Course Biology, we’ll see how conservation biology aims to restore habitat and preserve biodiversity. Along the way, we’ll see how environmental damage impacts human communities, and learn about wolves’ return to Yellowstone National Park.

Chapters:
Introduction to Conservation Biology
Human Impact
Environmental Injustices
Restoration Ecology
Conservation
Review & Credits
Credits

Hank wraps up Crash Course Ecology by taking a look at the growing fields of conservation biology and restoration ecology, which use all the moves we've learned about in the past eleven weeks, and applies them to protecting ecosystems and to cleaning up the messes that we've already made.

Chapters:
1) Types of Diversity
2) Conservation Biology
A) Small Population Conservation
B) Declining Population Conservation
3) Restoration Ecology
A) Structural Restoration
B) Bioremediation
C) Biological Augmentation

In which Craig Benzine teaches you about the compromises met in ratifying the U.S. Constitution. The United States didn’t always have its current system of government. Actually, this is its second attempt. Craig will delve into the failures (and few successes) of the Articles of Confederation, tell you how delegates settled on a two-house system of representation, discuss the issues of slavery and population that have been embedded into our constitution, and fire up the clone machine to discuss how federalists and anti-federalist opposition provided the U.S. a Bill of Rights. And who knows, maybe all this talk of compromise will even inspire Craig and eagle to find some middle ground.

Today we explore the penultimate ethical theory in this unit: contractarianism. Hank explains Hobbes’ state of nature, implicit and explicit contracts, as well as the Prisoner’s Dilemma, and the benefits, and costs, of violating contracts.