Posted on December 14, 2022 (Updated on July 9, 2025)
The cycle of water
Natural EnvironmentsThe water on earth is always on the move. Huge amounts of it are constantly moving – between sea, air and land – in an eternal cycle in which not a drop is lost. The motor of the water cycle is the sun: it heats the water of the oceans, lakes and rivers so much
Posted on December 14, 2022 (Updated on July 9, 2025)
The cycle of oxygen
Natural EnvironmentsThe air we breathe contains about one fifth oxygen. This gas is invisible, without smell and without taste – but it is vital for us. Because we need oxygen to gain energy in our metabolism. Without this gas, neither humans nor most animals can survive. Almost all the oxygen in the air is produced by
Posted on December 14, 2022 (Updated on July 9, 2025)
The blue planet
Natural EnvironmentsSeen from space, the earth’s sphere appears a strong blue. This is because almost three quarters of the earth is covered with water. Although water is transparent in small quantities, from a certain depth it takes on an increasingly strong blue shimmer. Because we see the mighty oceans as blue, the Earth is also called
Posted on December 14, 2022 (Updated on July 9, 2025)
Delta – watercourse between river and sea
Natural EnvironmentsMighty and sluggish, the Nile pours into the Mediterranean. Like all large rivers flowing through a plain, the African stream slows down towards its mouth. From the slow flow, the cargo of eroded debris and sand sinks to the bottom and is deposited. With these deposits, the river builds its own obstacle that it has
Posted on December 14, 2022 (Updated on July 9, 2025)
The Sea Shapes Coasts
Natural EnvironmentsWherever seawater meets dry land, we speak of a coast. Because the coast is exposed to the force of the sea without interruption, it is constantly changing. How strongly the water gnaws at the mainland depends on the strength of the rock, the height of the waves, the ocean currents and the tides. Gentle ocean
Posted on December 14, 2022 (Updated on July 9, 2025)
The global wind system
Natural EnvironmentsThe air masses of the atmosphere flow around the globe: they rise and fall, meet and mix. However, this does not happen in wild confusion, but the winds follow a very specific pattern. This global wind system (also called planetary circulation) is influenced above all by solar radiation and the Coriolis force. The tireless circulation