Reaction of ammonia with hydrogen chloride

Ammonium chloride is the result of the reaction of ammonia and hydrogen chloride

Aurora cruiser ship (1900)

The name of the Russian armoured cruiser became well known during the October Revolution of 1917.

Cube

This animation demonstrates the components (vertices, edges, diagonals and faces) of the cube, one of the Platonic solids.

Cannon operation (18th century)

The cannon was an important type of firearms at the beginning of modern history, widespread both on land and water.

Venice in the Middle Ages

Medieval Venice owed its wealth to its flourishing maritime trade.

Mycenae (2nd millenium BC)

The city with advanced culture was the first settlement in history to have a citadel.

Archaeological excavation (pit house)

Large construction sites provide archaeologists searching for artefacts with a great deal of work.

Cube of cubes

An exercise about the regular hexahedron built from unit cubes to help deepen your knowledge of cubes.

Archimedes’s military inventions (3rd century BC)

Archimedes was one of the most brilliant Greek scholars of ancient times, who made his mark with military inventions as well.

Medieval smithy

The work of smiths – one of the first professions in history – became even more important in the Middle Ages.

Nitrogen cycle

Atmospherical nitrogen is bound by bacteria and used by living organisms in the form of various compounds.

Golden Gate Bridge (San Francisco, 1937)

The suspension bridge that stretches above the strait between San Francisco Bay and the Pacific Ocean was opened in 1937.

Karst region (intermediate)

Karst formations include dolines and dripstones.

RT-2PM Topol Intercontinental ballistic missile (Soviet Union, 1985)

A mobile, nuclear-capable ballistic missile developed at the end of the Cold War.

Farming techniques

Farming techniques evolved with the development of human civilisation in the Middle Ages and the Modern Age.

Paramecium caudatum

Common ciliated eucaryotic unicellular organisms widespread in freshwaters.

Climate zones

The Earth is divided into geographical and climatic zones, which result in the zonation of vegetation.

Seafloor map

The boundaries of tectonic plates can be seen on the seafloor.

Glacier (intermediate)

A glacier is a large body of ice that forms from snow, and is in constant, slow motion.

SM U-35 submarine (Germany, 1912)

Submarines had an important role in naval warfare as early as World War I.

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