Addition is a reaction in which the molecules of two or more substances unite without the formation of a by-product.
A cuboid is a polyhedron with six rectangular faces.
An exercise about the regular hexahedron built from unit cubes to help deepen your knowledge of cubes.
An entertaining game about different views of spatial objects.
Mercury is innermost and smallest planet of the Solar System.
Neptune is the outermost planet of the Solar System, the smallest of the giant planets
Medieval Venice owed its wealth to its flourishing maritime trade.
The cannon was an important type of firearms at the beginning of modern history, widespread both on land and water.
These excellent shipbuilders and sailors travelled great distances on the seas and rivers.
The work of smiths – one of the first professions in history – became even more important in the Middle Ages.
Farming techniques evolved with the development of human civilisation in the Middle Ages and the Modern Age.
The suspension bridge that stretches above the strait between San Francisco Bay and the Pacific Ocean was opened in 1937.
The Olympic Games, held in the town every 4th year after 776 BC made it one of the centres of ancient Greece.
A wide variety of torture devices were in use in medieval dungeons.
Typical working-class districts with unhealthy living conditions were built at the time of the Industrial Revolution.
During the substitution reaction the hydrogen atoms of methane are substituted with chlorine atoms, the by-product is hydrogen chloride.
Limestone is a widely and diversely used material.
The topmost layer of our skin is the epidermis, which contains melanocytes.
Fatty acid molecules consist of a polar head and a non-polar tail, therefore they are suitable for removing fat stains.
Hydrogen atoms within hydrogen molecules are held together by a covalent bond.