Landforms And Their Evolution
A landform is a small to medium-sized part of the Earth’s surface. Several related landforms together form a landscape. Each landform is produced by geomorphic processes and geomorphic agents such as: Every landform has its own shape, size and nature. Landforms keep changing over time due to the continued action of geomorphic processes and agents. […]
Movement Of Ocean Water
Ocean water is never still. It continuously moves in different forms because of wind, temperature, salinity, density, the Sun, the Moon and Earth’s rotation. The oceans show three main types of movements: Currents and waves are mainly horizontal movements, while tides are mainly vertical movements. Ocean currents move a huge amount of water in a […]
Oceanography
Oceanography is the science that studies oceans. Oceans cover about 71% of the Earth’s surface. They form the largest and most prominent feature of the planet. The world ocean is one interconnected body of saltwater, divided into five principal oceans: Oceanographic research has become important because oceans control climate, support marine life, provide resources and […]
Water In The Atmosphere
Water is present in the atmosphere mainly in the form of water vapour. Water vapour is important because it controls humidity, condensation, cloud formation and precipitation. Even though water vapour forms only a small part of the atmosphere, it plays a major role in weather and climate. Water Vapour And Humidity Water present in the […]
Atmospheric Circulation And Weather System
Air expands when heated and gets compressed when cooled. This creates differences in atmospheric pressure. Because of pressure differences, air moves from high-pressure areas to low-pressure areas. This movement of air creates winds. Winds redistribute heat and moisture across the planet. They help maintain a broad temperature balance at the planetary scale. When moist air […]
Composition And Structure Of Atmosphere
The atmosphere is the gaseous envelope surrounding the Earth. It is composed of: The composition of the atmosphere is not exactly the same at all heights. The proportion of gases changes in the higher layers of the atmosphere. On the basis of residence time and composition, atmospheric gases are divided into: Composition Of The Atmosphere […]
Solar Radiation, Heat Balance And Temperature
The Earth receives most of its energy from the Sun. This energy reaches the Earth mainly as shortwave radiation. The incoming solar radiation received by the Earth is called insolation. Since the Earth is a geoid or oblate spheroid, the Sun’s rays do not fall equally everywhere. They fall at different angles at different latitudes, […]
Rocks And Minerals
The Earth’s crust is made up of rocks and minerals. Minerals combine in different proportions to form rocks, while rocks form the base of soil, natural vegetation and land use. This chapter explains the major elements of the Earth’s crust, important rock-forming minerals, types of rocks and the rock cycle. Major Elements Of The Earth’s […]
Geomorphic Processes
The Earth’s surface is continuously reshaped by both internal and external forces. The changes brought by these forces in the form and structure of the Earth’s surface are called geomorphic processes. Geomorphic processes include natural mechanisms such as: These processes modify landforms over time. The internal forces are called endogenic forces, while the external forces […]
Distribution Of Oceans And Continents
The continents and oceans have not always been in their present positions. At present, continents cover about 29% of the Earth’s surface, while oceans cover about 71%. Geological evidence shows that continents and ocean basins have changed their positions over millions of years. Different theories were given to explain this distribution. The major theories related […]