These excellent shipbuilders and sailors traveled great distances on the seas and rivers.
Saturn is the second largest planet in the Solar System, easily recognisable by its rings.
The ´Flying Fortress´ was developed for the United States Army Air Force by Boeing
Addition is a reaction in which the molecules of two or more substances unite without the formation of a by-product.
Large-scale ammonia production requires high temperature and pressure and the presence of iron as a catalyst.
The warship having several rows of oars was the typical warship of the Hellenistic era.
Large construction sites provide archeologists searching for artifacts with a great deal of work.
A cuboid is a polyhedron with six rectangular faces.
The first calendars and time-measuring instruments were already used by ancient Eastern civilizations.
Ammonium chloride is the result of the reaction of ammonia and hydrogen chloride
The dissolution of zinc in hydrochloric acid produces hydrogen gas.
The American Civil War was fought between the Confederacy and the Union.
Several analogous types of eyes have developed independently through convergent evolution.
The solution of hydrogen chloride in water is called hydrochloric acid.
This effective strategy was based on the fast and synchronized attack of different branches of the army.
Edison´s invention records and plays sound from a cylinder, while Berliner´s apparatus uses a disc.
An entertaining game about different views of spatial objects.
An exercise about the regular hexahedron built from unit cubes to help deepen your knowledge of cubes.
Submarines had an important role in naval warfare as early as World War I.
In alkaline batteries electric current is generated by electrochemical reactions