earth
Just like water, air and other natural elements, the soil may be considered a resource; it is, however, a non-renewable resource (FAO, 2015; APPA, 2012) – or a potentially renewable one if it is considered from a geological point of…
earth
The highest waterfalls in the world are located in Venezuela. The famous Salto Angel is 979 metres high. The widest waterfall is in Asia, in Laos: it is the Khone waterfall and, although it is only 70 m high, it…
earth
One of the most famous volcanic disasters was the eruption of Vesuvio in 79 A.D., which destroyed the cities of Ercolano and Pompei. The stages of the eruption were carefully described by Plinio il Grande: the eruption started with an…
earth
The activity of some volcanoes is characterized by violent explosions that break the magma into fragment of different size. Those bits of magma are launched high and then fall down at very high speed, like a burning cloud that hits…
earth
In order to understand the number of factors that make a water undersaturated or oversaturated, there is an experiment that we can carry out in the kitchen while we wait for the water to boil before cooking pasta. If we…
earth
A hill is a natural rise of the Earth’s surface. Generally, it is less than 600 metres high: it is lower than a mountain and has a less sharp shape. Some hills (so-called building hills) originated from the deposit of…
earth
The longest caves in the world are in Kentucky, the caves of Mammoth, which are 560 metres long. Other long karstic landscapes are in China, on the Shan plateau; in Australia, in the Nullarbar region; in North Africa, on the…
earth
One of the most common beliefs is that in caves the air is often stuffy, unhealthy, low in oxygen content and at times saturated with toxic gases. As a matter of fact, this erroneous belief stems from the confusion between…
earth
In South America plains are different from North to South. Plains in the north are called llanos and they are dry lands in the dry season, while during the rainy periods they are covered by very high vegetation. More in…