John Dickerson discusses how the sitting president's party typically performs in midterm 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.

Learn about the Doppler effect and how it explains the change in frequency of a wave when its source and an observer are moving. Created by Sal Khan.

Understanding the differences between the dot and cross products. Created by Sal Khan.

The diagram created, which explains the commercial name of drugs PCBs and PBBs and the reason why they being band.

Review of Enterprise Value and comparing it to EBITDA. Created by Sal Khan.

An overview of the life and teachings of Jesus Christ and the birth of Christianity.

An overview of the stories of the Torah (first 5 books of the Hebrew Bible and the Christian Old Testament).

An overview from the first kings of a unified Judah and Israel to the beginning of the Jewish Diaspora with the destruction of the Second Temple.

Is a ring from a ninth-century Viking grave a surprising find, or a reflection of the larger trade patterns in early medieval Europe and the Middle East? Vikings traded and raided throughout Europe and as far as the Abbasid Caliphate in the Middle East. Political circumstances and environmental factors shaped these patterns of trade.

Earnings, EPS (earnings per share) and how they relate to the income statement and balance sheet. Created by Sal Khan.

Earth ƒ??was formed approximately 4.6 billion years ago, likely as the result of a supernova (star explosion). The debris from this explosion began to collapse in on itself due to gravity, forming the sun. Gravity continued to draw the remaining particles together, clumping them into larger bodies, ultimately forming Earth and the other planets in our solar system. Created by Sal Khan.

Communities are dynamic and change over time, and we can observe this process with particular clarity after a disturbance or on new land. Learn about primary and secondary succession, as well as pioneer species. Created by Sal Khan.

Ecology is the study of how living things interact with each other and their environment. This includes living things (biotic factors) and non-living things (abiotic factors).

Economic growth is an expansion of the capacity to produce goods and services. Economists traditionally believed that expanding the stock of capital leads to economic growth. In this video, we explore the important link between investment and growth using the PPC model. Created by Sal Khan.

Economic models are a way of taking complicated ideas and events and breaking them down into their most important characteristics. We use models in economics so that we can focus our attention on a few things instead of getting bogged down a lot of details. In this video, learn more about the role that models play in economics, and the importance of the assumptions that underlie those models.