In benzene there are sigma bonds and delocalised pi bonds between carbon atoms.
Learning about the geographic location, capitals and flags of the world´s countries through exercises in three levels of difficulty.
Several ingenious instruments have been invented over the centuries to help in navigating the seas.
Standing bodies of water can form in depressions on the surface by both endogenic and exogenic forces, as well as by human activity.
Medieval Syrian water wheels were used to convey water to distant areas.
Major phases in the history of theories and views about the structure of the atom.
Energy released during nuclear fission can be used for civilian or military purposes.
The Suez Canal is an artificial waterway connecting the Red Sea and the Mediterranean Sea.
Human blood consists of blood cells and plasma.
The primary duty of these Japanese warriors was to serve their feudal lords, even at the cost of their own lives.
Ancient Egyptians worshipped a large number of gods and goddesses.
A selection of legendary buildings from the history of civilisation.
Bacteria are unicellular organisms that have no nuclei and are a few micrometres in length.
The steam engine, perfected by the Scottish engineer James Watt, revolutionised technology.
This animation demonstrates the development of the human embryo and foetus.
Short-lived but extremely powerful tornadoes can cause a great deal of damage.
These great scientists had a tremendous impact on the advancement in physics.
Dry land on the surface of Earth is divided into continents which are separated by oceans.
We can travel on dual carriageways on the motorway.
This animation presents some interesting facts in the field of astronomy.