How does an Archimedes screw work?

© SpaceX/Reuters; music © Ian Post/Artlist.io

SpaceX's Starship V3 megarocket launched on May 22, 2026.

Encyclopædia Britannica, Inc.

Muslim women working in a factory.

Encyclopædia Britannica, Inc.

Learn about the origins and diversification of uncrewed aerial vehicles, or drones, from early military models to modern consumer-level devices.

Encyclopædia Britannica, Inc.

Overview of the International System of Units.

Encyclopædia Britannica, Inc.

Learn more about the six basic types of simple machines.

Public Domain

The gas mask became a part of modern warfare with the introduction of chemical weapons in World War I. With the growth of total warfare and the targeting of civilians by air forces during World War II, the gas mask became a familiar part of daily life during wartime. In this video, English schoolchildren practice putting on and breathing through gas masks.

NASA

Apollo 15 commander David Scott dropping a 1.32-kg (2.91-pound) aluminum geological hammer and a 0.03-kg (0.07-pound) falcon feather on the surface of the Moon and proving that objects undergo the same acceleration in gravity, August 2, 1971.