This is the second of two videos where Sal derives Bernoulli's equation. In the second half of the video Sal also begins an example problem where liquid exits a hole in a container. Created by Sal Khan.

The Bhakti (devotional love) movement gains momentum during Medieval India, highlighting an alternative path for Moksha/Liberation in Hinduism.

Crash Course is a fast, funny, irreverent look at history. In this episode, brothers John and Hank Green gives us their take on what makes Big History so darn important.. Created by Big History Project.

Why does the Civil War matter? Kim discusses the importance of the Civil War and its effects on American society.

Businessman and philanthropist Bill Gates looks towards a future of sustainable energy and worldwide education. Created by Big History Project.

The first ten amendments to the US Constitution are known as the "Bill of Rights." These amendments protect individual liberties and limit the power of the federal government.

Adafruit founder Limor Fried and program manager Federico Gomez Suarez explain how computers represent numbers, text, images, and sound using tiny electric signals.

This 17-minute video lesson looks at understanding the structure of a muscle cell. [Biology playlist: Lesson 50 of 71].

This 14-minute video lesson provides an overview of B cells (B lymphocytes) and how they are activated and produce antibodies. [Biology playlist: Lesson 53 of 71].

This 18-minute video lesson provides an introduction to bacteria. [Biology playlist: Lesson 18 of 71].

This 17-minute video lesson looks at C-4 Photosynthesis: How some plants avoid photorespiration. [Biology playlist: Lesson 33 of 71].

This 9-minute video lesson looks at how CAM Plants are able to fix carbon at night so they don't have to keep their stomata open during the day. [Biology playlist: Lesson 34 of 71].

This 7-minute video lesson provides a correction to Sodium and Potassium Pump Video. [Biology playlist: Lesson 43 of 71].

This 10-minute video lesson discusses how cytotoxic T-Cells get activated by MHC-I/antigen complexes and then proceed to kill infected cells. [Biology playlist: Lesson 56 of 71].

This 28-minute video lesson provides an introduction to DNA. [Biology playlist: Lesson 6 of 71].

This 19-minute video lesson looks at diffusion and osmosis. [Biology playlist: Lesson 36 of 71].