Using the Russian Primary Chronicle to explore the early Nordic and Slavic beginnings of the "Land of Rus'" or the "Kievan State", including the start of the Rurukid Dynasty by Rurik.

John Dickerson discusses differences in turnout trends between midterm and presidential election years. John Dickerson is co-host of CBS This Morning. He was previously CBS News' Chief Washington Correspondent, Political Director and anchor of Face The Nation. Dickerson is also a contributor to Slate's Political Gabfest and to The Atlantic. During the 2016 presidential campaign, Dickerson moderated CBS News' two presidential debates. Prior to CBS, Dickerson was Slate Magazine's Chief Political correspondent and covered politics for twelve years for Time magazine.

John Dickerson discusses how the position of Speaker of the House has changed over time. John Dickerson is co-host of CBS This Morning. He was previously CBS News' Chief Washington Correspondent, Political Director and anchor of Face The Nation. Dickerson is also a contributor to Slate's Political Gabfest and to The Atlantic. During the 2016 presidential campaign, Dickerson moderated CBS News' two presidential debates. Prior to CBS, Dickerson was Slate Magazine's Chief Political correspondent and covered politics for twelve years for Time magazine.

John Dickerson tells us how Reagan's policies still affect the United States. John Dickerson is co-host of CBS This Morning. He was previously CBS News' Chief Washington Correspondent, Political Director and anchor of Face The Nation. Dickerson is also a contributor to Slate's Political Gabfest and to The Atlantic. During the 2016 presidential campaign, Dickerson moderated CBS News' two presidential debates. Prior to CBS, Dickerson was Slate Magazine's Chief Political correspondent and covered politics for twelve years for Time magazine.

John Dickerson tells us about how congressional elections have changed, becoming more closely associated with the incumbent president's performance in office. John Dickerson is co-host of CBS This Morning. He was previously CBS News' Chief Washington Correspondent, Political Director and anchor of Face The Nation. Dickerson is also a contributor to Slate's Political Gabfest and to The Atlantic. During the 2016 presidential campaign, Dickerson moderated CBS News' two presidential debates. Prior to CBS, Dickerson was Slate Magazine's Chief Political correspondent and covered politics for twelve years for Time magazine.

Given that hiring more workers gives more revenue, but also has additional cost, what is the optimal amount of labor to hire? We begin thinking about this as well as briefly discuss another type of competition: monopsony labor markets. Created by Sal Khan.

Price controls reallocate surplus between buyers and sellers. In this video we explore how that happens with a price ceiling or a price floor.

S-wave shadow and P-wave detection patterns give us information about the core. Created by Sal Khan.

Introduction to the major organ systems of the human body, general anatomy, and how the different organs work together. Includes videos, articles, flashcards, and quizzes.

Overview of fertilization and early human development. From conception leading to a zygote to blastocyst, embryo and fetus.

Napoleon's escapes from Elba and retakes control only to be defeated at Waterloo. Created by Sal Khan.

Explore the mechanics of hybrid adjustable-rate mortgages, which are a blend of a fixed rate mortgage and an adjustable rate in this video, including how they work and when they might be advantageous.

How hydrolysis can break down polysaccharides (carbohydrates) like starch, cellulose, chitin and glycogen.