Physical Geography

The theory of continental drift was presented by a German geologist, Alfred Wegener in 1910. He suggested that at the beginning of the Mesozoic era (200 million years ago), all the continents of the earth were united together. These continents were united to form a single supercontinent, which he called “Pangaea”. The huge ocean, that surrounded it, he called “Panthalassa”. Wegener proposed that this vast continent began to break up into […]

Isostasy C.E Dutton, in 1889, suggested that a gravitational balance exists between the elevated masses (i.e. continents) and ocean basin of the earth’s crust. It is believed that the lithosphere floats on the top of the partially molten substratum (asthenosphere) much like logs float on water. Mountains stand high because they are composed of rocks of low density, and ocean basins are low because they are made up of rocks […]

The mantle is a layered part of the earth, which is located just beneath the crustal layer of the earth. The Earth’s crustal surface (lithosphere) rides atop the asthenosphere. The asthenosphere is the upper layer of the Earth’s mantle, in which there is relatively low resistance to plastic flow and convection is thought to occur. While the lower part of the mantle is very hot and molten. Mantle convection means the movement […]

The knowledge about the interior structure and composition of the earth has a long history. Before seismic tomography, scientists knew very little about the interior of the earth. The study of the passage of seismic waves through the earth has helped in knowing the structure of the earth’s interior and in defining the physical properties of various layers. The seismic waves travel at different velocities depending on the nature of […]

What is radioactive decay? Radioactive elements continuously release their protons and neutrons and form new daughter products. The radioactive elements are often known as the “parent”, and the element resulting from the decay is known as the “daughter product”. As the number of protons and neutrons is different in parent and daughter products, therefore the daughter product becomes a quite different element. This process is known as radioactive decay, and […]

Physical Geography Definition Before going to the definition of physical geography, let’s have a brief introduction to Geography and its branches. Geography is a branch of natural science, devoted to the study of the lands, features, inhabitants, and phenomena of Earth. Geography is an all-encompassing discipline that seeks an understanding of Earth and its human and natural complexities—not merely where objects are, but also how they have changed and come […]

Age of the Earth The age of the Earth as determined by the current method of radiometric dating is about 4600 million years. Before the discovery of radiometric dating, several attempts were made to determine the age of the Earth. The important ones are as follows. From the discovery of organic evolution From the rate of sedimentation From the salinity of seawater From the rate of cooling From the history […]

The Earth came into being around 4.54 billion years ago. In general, the theories about the origin of the Earth and Solar System can be divided into two groups: (i) evolutionary theories, and (ii) catastrophic theories. The earlier theories include mainly the evolutionary. The evolutionary theories regarding the origin and evolution of Earth are the Nebular Hypothesis, the Revised Nebular Hypothesis as well as Binary Star Theories of origin of […]

Solar System Solar System and Planets of the Solar System are of greater importance in science studies. The Earth on which we live, and the only known abode of living creatures is a planet, which is a member of the Solar System. Eight planets and the Sun are the main bodies of the Solar System. All these planets revolve around the Sun in their fixed orbits. Their motion is balanced […]

What is Geography? Geography is a fundamental branch of Earth Science, that deals with the study of physical features, natural processes of Earth, population, environment, and relationships among people. Geography is a multidisciplinary field that connects elements of the natural sciences, social sciences, and humanities to understand the Earth’s landscapes, environments, and the processes that shape them. We can further divide it into two main branches: Physical Geography: The Earth’s […]