Common salt is dissolved by water: polar water molecules form a coat around the ions.
Treated sewage water can be used in agriculture and industry.
Neptune is the outermost planet of the Solar System, the smallest of the giant planets
As opposed to underground mines, in open-pit mines the layers covering coal are removed, coal is extracted on the surface.
The building material of the cell walls and fibres of plants.
The aircraft manufactured by the British de Haviland company was the world's first mass-produced commercial jetliner.
The first calendars and time-measuring instruments were already used by ancient Eastern civilisations.
Oxygen carrier protein in our red blood cells.
Formic acid is the simplest carboxylic acid.
A type of sugar found in mammalian milk.
A white, water-soluble, sweet compound known as sugar.
The medieval bell tower of the Cathedral of Pisa is the most famous leaning tower of the world.
The submarine designed by the Spanish inventor Narcís Monturiol was a pioneering work in the history of underwater navigation.
The warship having several rows of oars was the typical warship of the Hellenistic era.
The marathon running event was instituted in commemoration of the run of a Greek soldier after the Battle of Marathon, fought between the Athenian and the...
Concave and convex lenses are used for the correction of short-sightedness and far-sightedness.
English sailing ships were among the best ships in the 17th-19th centuries.
This effective strategy was based on the fast and synchronised attack of different branches of the army.
The Möbius strip and the Klein bottle are special two-dimensional surfaces with only one side.
Solid, white substance, a constituent of vegetable oils and animal fats.