During its orbit around the Earth, the visibility of the Moon's illuminated part constantly changes.
The palace of Charlemagne was not only the centre of his empire, but also a centre of culture.
Bones of the lower limbs are connected to the trunk by the pelvis.
A fuel cell provides environment-friendly electric energy produced by the chemical reaction between oxygen and hydrogen.
This animation explains the technology of shale gas extraction.
Scoliosis is a medical condition in which a person's spine has a lateral deviation.
The concentration camp established on Polish territory was the administrative centre of a huge camp complex.
Electric current can be generated by rotating an armature loop in a magnetic field.
Keeps were typical buildings in the Middle Ages, also built independently from castles.
The German engineer Otto Lilienthal was the first person to make successful flights with a glider designed by himself.
Thermal power stations convert energy released during the combustion of fossil fuels or renewable resources into electricity.
This animation demonstrates the five regular three-dimensional (or Platonic) solids, the best known of which is the cube.
The urinary system serves for the removal of harmful and useless materials from the body.
Several analogous types of eyes have developed independently through convergent evolution.
The first calendars and time-measuring instruments were already used by ancient Eastern civilisations.
Machinery that pumps crude oil to the surface
The building material of the cell walls and fibres of plants.
Venus is the 2nd planet from the Sun, the brightest object on the night sky (after the Moon).
A white, water-soluble, sweet compound known as sugar.
Learn the concept of colours, numbers, letters and shapes while playing