Observe XB-70A Valkyrie landing at Edwards Air Force Base, California

Contunico © ZDF Studios GmbH, Mainz

How do the waxy coating on some fruits helps them survive different climates?

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Packing cans of fish in Prospect Harbor, Maine.

© American Chemical Society (A Britannica Publishing Partner)

Learn about the development and applications of glass paint, which is made of silica glass and formulated to reflect sunlight, protecting surfaces from heat and damage.

© MinutePhysics (A Britannica Publishing Partner)

Learn about angular momentum.

World War I is remembered for its terrible combination of technological ingenuity and strategic indecisiveness. The growth of army sizes, and the introduction of new weapons like long-range heavy artillery and chemical gas, turned combat into mechanized carnage on an unprecedented scale. It also made it more essential than ever for armies to gather information about enemy troops and weapons. Stationary balloons were used for observation and artillery spotting as early as the American Civil War but found widespread use in World War I. This video shows the view from a balloon over the Western Front.

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Learn more about the role technology plays in the lives of modern children.

Encyclopædia Britannica, Inc.

Newton's third law as illustrated by a rocket launch.