Two-stroke engine

A two-stroke engine is a type of internal combustion engine with a cycle of only two (power) strokes.


This animation shows optical and radiotelescopes used in astronomical observation.

Horse chestnut

This animation demonstrates how horse chestnut trees change throughout the seasons

Types of bridges

Types of bridges include beam-, arch-, suspension-, cantilever and truss bridges.

Types of gears

Two meshing gears transmit torque during their rotational motion.

Edible frog

This animation demonstrates the anatomy of amphibians through the example of a common species of frogs.

Amoeba proteus

Widespread heterotrophic unicellular organisms with constantly changing shapes

Fat molecule

Three saturated fatty acid molecules linked to a glycerol molecule.

Common earthworm

The anatomy of annelids is demonstrated through the example of the common earthworm.


Jellyfish are free-swimming marine animals, a species of Cnidaria, the most ancient group of Eumetazoans.


The most ancient group of animals, they live underwater, lack real tissues and body symmetry.

Secondary structure of proteins

Polypeptide chains are composed of amino acids and can appear in alpha-helix or beta-sheet form.

Oil molecule

Triglycerides containing unsaturated fatty acids are liquid at room temperature.


Observatories are often built at high elevations to minimise the effects of atmospheric turbulence

The evolution of data storage

The capacity of data storage devices have increased at an incredible rate during the past decades.


Chlorophyll is a photosensitive green pigment found in plants; it absorbs light energy, thus plays a vital role in photosynthesis.

European honeybee

Honeybees produce a sweet and nutritious substance, honey.

Inca warrior (15th century)

The Incas´ rudimentary weapons were inadequate in their struggle against the Spanish Conquistadors.

System of public utilities

System that satisfies consumers’ demands of water supply, wastewater disposal, electricity, heat and gas supply and telecommunication.

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