PHYSICAL GEOGRAPHY PHYSICAL GEOGRAPHY physical geography is the studies of non-human parts of the Earth —its landscapes and rocks, its atmosphere, and its rivers, lakes, and oceans —as well as the plants and animals that inhabit these places. It is similar to Earth science, but physical geography is more concerned about where things are. There are many different branches of physical geography.eg Branches of physical geography 1. Biogeography Biogeographers look at where plants and animals live. They are especially interested in biomes – biomes are large regions where particular communities of plants and animals live. 2. Geology and geomorphology Geologists study rocks and minerals, and the Earth’s crust and interior. Geomorphologists study landforms and processes that shape the landscape 3. Meteorology and climatology Meteorologists look at the atmosphere and try to forecast the weather. Climatologists study climates – the average weather in each region of the world. HUMAN GEOGRAPHY Human geography focuses on people’s relationships with each other and the surrounding environment. It includes two main themes of geography: human-environment interaction and movement. It studies how people interact with each other and with different kinds of environment. Human geographers are interested in the environments people create for themselves, both in rural areas and in cities Branches of Human Geography 1. Urban geography Cities are a subject of study for urban geographers. They try to understand why and how things change in cities, and how cities make links across the world 2. Economic and social geography Economic geographers study where economic activities (such as industry and farming) take place. Social geographers look at the distribution of different groups of people. 3. Population geography Population geographers are interested in where people are born, where they die, and how they move about. They also study how populations change. WORLD PHYSICAL MAP EARTH’S STRUCTURE Our planet is a giant sphere of rock and metal surrounded by layers of water and air. The earth is made up of three layers: the core, the mantle, and the crust. More than 70 percent of the crust is covered by oceans, and the rest forms the islands and continents where we live. Earth’s formation The Earth formed about 4.54 billion years ago from a cloud of rock, dust, and gas surrounding the newly formed sun. Gravity pulled this space debris together to form a sphere, which eventually melted and developed a layered structure of metal and rock. This structure then cooled down, finally becoming cool enough to support liquid oceans and an atmosphere. Accretion Cooling Rocks drifting in space started to be pulled When accretion slowed down, the planet together by their own gravity to form one cooled. Most of its rock solidified, forming a large object, and eventually a planet. This series of layers around the still-hot metal growth by gradual accumulation of material core. is called accretion Oceans and atmosphere Meltdown As more rocks smashed into the planet, the energy The gases that erupted from volcanoes from all these impacts converted to heat. The planet formed the early atmosphere. Water vapor began to melt, and most of the heavy metal from its turned into clouds and then rain, which eventually filled the oceans. rocks sank to form the core THE STRUCTURE OF THE EARTH There are four main layers within the Earth, » The inner core is solid. It is five times denser than surface rocks. » The outer core is semi-molten. » The mantle is semi-molten and about 2900km thick. » The crust is a solid and is divided into two main types: oceanic crust and continental crust. The depth of the crust varies between 10 km and 70 km Continental crust is mostly formed of granite. It is less dense than the oceanic crust. Because it is more dense the oceanic crust plunges beneath the continental crust when they come together. THE LAYERS OF THE EARTH INTRODUCTION TO THE SOLAR SYSTEM The solar system is made up of the Sun, eight planets, satellites, and other celestial bodies. Celestial bodies are objects like Sun, moon, stars and others that shine in the night sky. Some celestial bodies are very big and are made up of gases and heat. They have their heat and light which is emitted in large amounts. These celestial bodies are called stars and our Sun is a star. The sun, the moon, and all those glittering objects in the night sky are called celestial bodies. The Sun The sun is in the center of the solar system. It provides the pulling force that binds the solar system It’s made of very hot gases mainly hydrogen (70%) and helium (30%). Has a diameter of 1392000km. Surrounded by a layer of gas which has boiled from its surface which is called corona. Rotates on its own axis in anticlockwise direction Diagram: Our Solar system The 8 planets in the solar system are: 1. Mercury 2. Venus 3. Earth 4. Mars 5. Jupiter 6. Saturn 7. Uranus 8. Neptune MOTIONS OF THE EARTH Rotation and Revolution are two motions of the earth. When the earth spins or rotates around its axis, that movement of spinning is called the Rotation of Earth. And when the earth spins or revolves around the sun, that movement is called the Revolution of Earth. Rotation • • • • • • Rotation is the movement/spinning of the Earth, on its axis. The axis of the Earth, which is an imaginary line, makes an angle of 66/2° with its orbital plane. The portion facing the Sun experiences day, while the other half away from the Sun experiences night. The circle that divides the day from night on the globe is called the circle of illumination. The Earth takes about 24 hrs to complete one rotation around its axis, it is known as earth day The direction of earth’s rotation is from West to East.
