The main protagonists of World War II were tanks.
One of the oxoacids of nitrogen. Colourless, moderate acid with a pungent odour, that exists only in aqueous solution.
A compound formed as white smoke during the combustion of phosphorus.
Robert Fulton American engineer created the first operational steam-powered ship.
Wind power stations convert the kinetic energy of the wind into electricity.
The least tightly packed crystal structure.
The staggered conformation of ethane is more stable than the eclipsed conformation.
Electrochemical processes in a lead-acid battery produce electric current.
The Hubble Space Telescope orbits outside the distorting influence of Earth´s atmosphere.
Metals forming hexagonal metallic lattices are rigid and difficult to machine.
Extinct proboscidea closely related to today's elephants, often hunted by prehistoric man.
The name of the Russian armoured cruiser became well known during the October Revolution of 1917.
Learn the concept of colours, numbers, letters and shapes while playing
One of the most common types of flatworms.
Colourless, moderate acid, only known in aqueous solution.
The first dwellings in human history provide a lot of information about the lifestyle of our ancestors.
Farmhouses in the Middle Ages were simple, single-storey structures built from earth, mud and wood.
A fuel cell provides environment-friendly electric energy produced by the chemical reaction between oxygen and hydrogen.
Several analogous types of eyes have developed independently through convergent evolution.
As the Roman Empire expanded, military camps were established on the newly conquered territories.