Native American settlement (Crow Nation)

The Crow are Native Americans who inhabited the Yellowstone River valley.

Southern wood ant

An ant colony consist of a queen, male ants and workers.

Volume of a tetrahedron

To calculate the volume of a tetrahedron we start by calculating the volume of a prism.

Two-stroke engine

A two-stroke engine is a type of internal combustion engine with a cycle of only two...

Reed and bulrush

Cosmopolitan monocots inhabiting watersides.

Apple tree

The apple is one of the most popular fruits around the world.

Topography of the Earth

The animation presents the largest mountains, plains, rivers, lakes and deserts of the Earth.


Paper was invented more than two thousand years ago.

Secondary structure of proteins

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

Oil tanker

Oil tankers appeared in the late 19th century; today they are among the largest ships.


This animation shows optical and radiotelescopes used in astronomical observation

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...

Monsters of the Palaeozoic: sea scorpions

Eurypterids are an extinct group of Palaeozoic aquatic arthropods.

Fat molecule

Three saturated fatty acid molecules linked to a glycerol molecule.


Modern Slavs live in 14 European countries that can be classified into 3 groups.

Hot air balloon

A hot air balloon is a balloon aircraft which is lifted by hot air.

Water turbine, generator

Water turbines convert the kinetic energy of water into electric current.


One of the most important monocot crops.


Regular dice can be used for solving statistical and probability exercises.

Added to your cart.