The Gregorian calendar

Developed nearly 500 years ago, it is a variant of the Julian calendar. Today it is the most widely used calendar.

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The rock cycle

Due to the effect of both exogenic and endogenic forces, rocks constantly change. This is called...

Plate tectonics

Plate tectonics is a theory dealing with the movement of plates.

Solar eclipse and lunar eclipse

We can observe quite interesting astronomical phenomena when the Earth, the Sun and the Moon align.

Glacier (basic)

A glacier is a large body of ice that forms from snow, and is in constant, slow motion.

Why is seawater salty?

Water covers about 71% of the Earth’s surface. But why are there two types of water on Earth,...

Eroded fault-block mountains

We can come across the remains of the Variscan and Caledonian mountain systems almost anywhere...

The weather forecast

The weather can be forecast with different meteorological instruments.

The process of physical and chemical weathering

Upon physical weathering the rock only falls into pieces, whereas during chemical weathering its...

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