Ancient Egypt was an early example of a massive civilization spanning thousands of years. Sal explains this history in an overview.

Conservators at the British Museum preparing an ancient Egyptian coffin for display in the exhibition Journey through the afterlife: ancient Egyptian Book of the Dead. © Trustees of the British Museum. Created by British Museum.

Preparing pieces of papyrus ready for display in the exhibition Journey through the afterlife: ancient Egyptian Book of the Dead. © Trustees of the British Museum. Created by British Museum.

From the Utah System of Higher Education (with special thanks to Dr. Nancy Ross). Video by Ydraw. Created by Nancy Ross.

Ancient Greek Temples at Paestum: Hera I, c. 560-530 B.C.E., Archaic Period; Hera II, c. 460 B.C.E., Classical Period; Temple of Minerva, c. 500 B.C.E. Archaic Period. A conversation with Dr. Beth Harris and Dr. Steven Zucker. Created by Beth Harris and Steven Zucker.

Used for the storage and shipment of grains, wine, and other goods, as well as in the all-male Greek drinking party, known as the symposium, ancient Greek vases were decorated with a variety of subjects ranging from scenes of everyday life to the tales of heroes and gods. The two most popular techniques of vase decoration were the black-figure technique, so-named because the figures were painted black, and the red-figure technique, in which the figures were left the red color of the clay. The black-figure technique developed around 700 B.C. and remained the most popular Greek pottery style until about 530 B.C., when the red-figure technique was developed, eventually surpassing it in popularity. This video illustrates the techniques used in the making and decorating of a black-figure amphora (storage jar) in the Art Institute of Chicago's collection. This video was produced with the generous support of a Long Range Fund grant provided by the Community Associates of the Art Institute of Chicago. It was created for LaunchPad, a program of digital interpretive materials that supplement the viewing of works of art on display in the Art Institute of Chicago's galleries. Created by Getty Museum.

Used for the storage and shipment of grains, wine, and other goods, as well as in the all-male Greek drinking party, known as the symposium, ancient Greek vases were decorated with a variety of subjects ranging from scenes of everyday life to the tales of heroes and gods. The two most popular techniques of vase decoration were the black-figure technique, so-named because the figures were painted black, and the red-figure technique, in which the figures were left the red color of the clay. The black-figure technique developed around 700 B.C. and remained the most popular Greek pottery style until about 530 B.C., when the red-figure technique was developed, eventually surpassing it in popularity. This video illustrates the techniques used in the making and decorating of a black-figure amphora (storage jar) in the Art Institute of Chicago's collection. This video was produced with the generous support of a Long Range Fund grant provided by the Community Associates of the Art Institute of Chicago. It was created for LaunchPad, a program of digital interpretive materials that supplement the viewing of works of art on display in the Art Institute of Chicago's galleries. Created by Getty Museum.

Why is Mesopotamia considered the "cradle of civilization"? Sal explains the history of the early empires on the Tigris and Euphrates rivers.

High level overview from Ancient Egypt to Babylon with reference to stories from the Old Testament.

This overview of Ancient Persia explains the origins of the term "Persia" and Zoroastrianism; it also puts the Median, Achaemenid, Seleucid, Parthian, Sassanian dynasties in context.

Thebes, the city of the god Amon, was the capital of Egypt during the period of the Middle and New Kingdoms. With the temples and palaces at Karnak and Luxor, and the necropolises of the Valley of the Kings and the Valley of the Queens, Thebes is a striking testimony to Egyptian civilization at its height.

Andrea Mantegna, San Zeno Altarpiece, 1456-59, oil on panel, 212 x 460 cm / 83 x 180 inches, comissioned by the Benedictine Abbot, Gregorio Correr (Basilica of San Zeno, Verona). Created by Beth Harris and Steven Zucker.

Andrea Pisano, Reliefs for the Campanile in Florence, c. 1336 Speakers: David Drogin and Beth Harris. Created by Beth Harris and Steven Zucker.

Introducing angular momentum conceptually starting from linear momentum. Also covers some real-life examples. Created by Sal Khan.

David explains the meaning of angular displacement, angular velocity, and angular acceleration. Created by David SantoPietro.

In uniform circular motion, angular velocity (𝒘) is a vector quantity and is equal to the angular displacement (Δ𝚹, a vector quantity) divided by the change in time (Δ𝐭). Speed is equal to the arc length traveled (S) divided by the change in time (Δ𝐭), which is also equal to |𝒘|R. And arc length (S) is equal to the absolute value of the angular displacement (|Δ𝚹|) times the radius (R).