• Geography is one of the oldest earth science and its roots date back in the works of the early Greek scholars. The word ‘geography’ was first used by the Greek scholar Eratosthenes in the third century B.C. Geo “Earth” and Graphy “to describe” literal meaning of geography is to describe about the earth’s surfaces. In other words “Geography is largely the study of the interaction of all physical and human phenomena and landscapes created by such interactions.” It is about how, why, and where human and natural activities occur and how these activities are interconnected.
• The purpose of geography was to provide a description of the physical features and conditions in different parts of the world. The earth is the only known planet with developed life in the universe. Like most of the celestial bodies, the earth is spherical in shape.

1. Solar System:

• Universe: Million of the Constellations of stars in the sky is called a Galaxy. Thousands of galaxies form the universe.
• Milky Way Galaxy: Million of stars including the sun and others celestial bodies which can be viewed with our eyes belongs to the Milky Way Galaxy. A white streak of the light can be seen on a clear night for few days, our ancestors called this as the Milky Way Galaxy. In India it is named as “Akash Ganga”
• Planets: Planets are celestial bodies which revolve around the sun on their elliptical paths called orbits. They do not have their own light and heat buy they reflect that of the sun. There are totally 8 planets in the solar system. While the Pluto has been degraded to Dwarf Planet. The 8 planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Except Mercury and Venus each planet has a natural satellite.
• Satellites: Satellites are objects that go around a larger object such as a planet. The moon is the only satellite that goes around the earth, our planet.
• Asteroids: Asteroids are also called as planetoids. These are big pieces of rock or rock and metal. The orbit around the sun between mars and Jupiter in their own elliptical orbit called Asteroid Belt.
• Meteors: Meteors are a streak of bright light that can be seen from Earth. When a meteorite enters the atmosphere Falling star or shooting star is the common name for the visible path of a meteoroid as it enters the atmosphere to become a meteor. If a falling star survives impact with the Earth’s surface, and then it is called a meteorite.
• Comet: It is exciting to see a comet in the night sky. It is a rock made of dust and ice .The long tail is seen because as the comet comes near the sun the ice melts and reflects the light of the sun.
• Moon: Moon is the natural satellite of the earth. It is made of rocks. It has no air. The surface of the moon has many craters and mountains. It does not have its own light and heat; it reflects the light of the Sun. It revolves around the earth on its elliptical orbit and it takes 27.3 days to complete one revolution. In 1959 the Satellite “Lunar 3” photographed the other side of the Moon. The Moon does not have an Atmosphere like earth. Water is not found in the liquid form but Moisture is Present.
• Land form such as Mountain and Valley that are found in the Earth surface are also found on the moon. Craters are another special feature of the moon. The sun is the only illuminating celestial body, in our solar system. Though the moon shines brightly during the night it ‘actually reflects the light of the sun. Like the earth the moon is also almost a sphere, therefore the side that faces the sun shines brightly while the other side is dark.
• Side faces the earth is called “New moon”. The side of the moon that shines brightly on the earth is called “Full Moon”. Chandrayaan – 1 was launched by India on 22.10.08 to probe the moon. Chandrayaan – 2 is being readied by ISRO to further investigate the moon which is to be launched soon.
• Sun: The sun is the biggest star in our solar system. It is a bright star and is at the centre of the solar system. The light from the sun gives energy and strength for things to grow. Without the light from the sun the earth would be a cold dark place. About three quarters of the suns mass consist of hydrogen, while the rest is mostly helium. Less than 2% consists of heavier elements, including oxygen, carbon, Neon, Iron and others.
• The sun rises in the East and sets in the west. When the sun rises, the stars become invisible. But when the sun sets in west the stars shine brightly.
• Mercury: This is the smallest and closest planets of the sun. It takes only 88 earth days to go round the sun once. It has no satellites and no atmosphere .
• Venus: It is the second planet in the solar family. It revolves around the sun from east to west. After the sun and the moon, Venus is the brightest natural object in the sky. It is also called the morning star or the evening star.
• Earth: The third planet from the sun is the Earth. It is the home to all living things as it fulfils their basic needs. The earth is neither too close nor too far away from the sun. It supports life and hence called the living planet. About 71% of earth surface is covered by water and 29% with land. The Earth is a big sphere. Our Earth is slightly bulged at the equator slightly flattened at the poles. The shape of our Earth is unique. Shape of the Earth is called as a Geoid.
• Mars: It is the fourth planet in the solar family. The minerals and the iron present in the soil in mars give red color to his planet. It is cold and dusty planets. It has two moons.
• Jupiter: It is the largest planet in the solar family and it is a gas filled planet rather than the rocks. It has around 63 natural satellites.
• Saturn: It is the second biggest planet in the solar family and it has rings around the planet.
• Uranus: It is the lightest of the outer planets. It has 27 known natural satellites.
• Neptune: It is the 8^th planet of the Solar system and it has 14 known natural satellites.
• Without the help of the telescope, you will be able to see the five planets, namely “Mercury, Venus, Mars, Jupiter, and Saturn with naked eye. But “Neptune and Uranus” can be seen only through a telescope. Before the sunrise and sunset you see the Mercury and Venus for few hours. These two planets appear only at the horizon. Venus rises a few hours before sunrise and therefore it is called as “The morning star”.
• The eight planets have been classified as Solid and Gaseous Planets. “Mercury, Venus, Earth and Mars are called Solid planets. While Jupiter, Saturn, Uranus and Neptune are Gaseous Planets.

The material of the crust is made up of rocks. The rocks are of different types. They are hard like granite, soft like clay and loose like gravel. Rocks have a great variety of color, weight and hardness.Rocks differ in their properties, size of particles and mode of formation. On the basis of mode of formation rocks may be grouped into three types:

2. Rocks

• Igneous b)Sedimentary and c)Metamorphic

Igneous Rocks:

• Igneous rocks are formed from solidified molten magma below or on the earth’s surface. As they comprise the earth’s first layer and all other rocks are derived from them, these are called the parent of all rocks or the ‘primary rocks’.

Sedimentary Rocks:

• These rocks are formed by successive deposition of sediments. These sediments may be the debris eroded from any previously existing rock which may be igneous rock, metamorphic or old sedimentary rock. Sedimentary rocks have layered or stratified structure. So these rocks are also called stratified rocks. Generally, these rocks have some type of fossil between their strata. Sedimentary rocks are widely spread on the earth surface but to a shallow depth.

Metamorphic rocks

• Metamorphic rocks are formed under the influence of heat or pressure on sedimentary or igneous rocks. Tremendous pressure and high temperature change the color, hard­ness, structure and composition of all types of pre-existing rocks. The process which bring about the change is known as Metamorphism and the ultimate prod­ucts, formed due to operation of such processes are defined as the metamorphic rocks

Relief Features:

• Mountains: Mass of land higher than the surrounding areas
• Hills are areas of high pieces of land but not as high as mountains
• Plateaus: Level areas of elevated land
• Plains: Areas of land with a little difference between highest and lowest points.
• Valleys: Narrow pieces of land between two mountains
• Peninsula: The land surrounded by water in three sides and land in one side
• The Indian sub continent is called Peninsula since it is surrounded by the Bay of Bengal in the east, the Arabian Sea in the west and the Indian Ocean in the south. On the northern side alone it is a stretch of land.
• Islands: Piece of land surrounded by water on all sides (e.g.) Sri Lanka, Andaman and Nicobar Islands, Lakshadweep
• Deserts: Large stretches of arid land where no vegetation except cactus and datepalms is found (e.g.) Thar – India, Sahara – Africa, Arizona – North America

4. Oceans and Water Bodies:

• The large water bodies are called oceans and seas. There are four large oceans on the Earth. They are The Pacific Ocean, The Atlantic Ocean, The Indian Ocean,  The Arctic Ocean. The Pacific Ocean is the largest ocean which covers more than one-third of earth’s surface.
• The Atlantic Ocean is the second largest ocean. Only the Indian Ocean has been named after the country. Besides these there are the Antarctica Sea, the Mediterranean Sea, Caspian Sea and Black sea which are also large water bodies.
• Waterfalls: Large volumes of water come gushing down from height to areas below.
• Rivers: Huge areas where water flows along the surface of land.
• Streams: A small areas of water flows along the surface of land and joins with a river.
• Lakes: Areas of water surrounded by land on all sides.
• The Ocean Bed/ the sea bed: The Ocean bed is not riot level ground. Even here we can see mountains, hill ranges, and mounds as on land. The earth quakes and volcanic eruption under the ocean bed are the reasons for the formation of the relief features.
• One Land Mass: During the formation of the earth there was a large land mass called Pangea. This land mass moved slowly and in the course of thousands of years continental plates were formed. North America, South America, Asia, Europe and Africa are connected to each other. Australia is surrounded on all four sides by water. Antarctica is totally covered by ice.
• Rotation: The earth spins with its 23 1/2⁰ tilted position on its own axis. It takes 24 hours or one day to complete one round. This movement of the earth on its own axis is called rotation. The axis joins North Pole and South Pole.
• Effects of rotation of the earth: It causes day and night Earth rotates from west to east [anti – clockwise]. So places in the east experience the day first. We understand that the sun rises in the east and sets in the west. This gives us a sense of direction.
• Revolutions: The annual motion of the earth around the sun along its ‘elliptical’ [oval shaped] orbit is called revolution. While spinning on its axis the earth also moves around the sun along its fixed path. The earth takes 365 ¼ days or 1 year to go around the sun once. This movement of the earth is called revolution.
• Effects of revolution of the Earth: The major effect of the revolution is the seasons that are caused in the earth. It changes from place to place.
• Seasons: Generally we talk about four seasons – spring (flowering season), summer (hot season), autumn (fall), and winter (cold season). The season changes once in three months. Spring: It is pleasant season that comes between winter and summer. We can see the new leaves on the trees. The plants are in full bloom. There is a promise of new birth and color in the spring time air. Summer: Summer is the hottest season out of the four. During this we have longer days. Autumn: Autumn is the season between summer and winter. The air begins to cool. The trees shed their leaves. This season does not occur in India because of its geographical location.
• Winter: Winter is the coldest season. During this season the days are short and nights are long. Snow fall occurs in some countries and hilly regions.

Seasons in India:

• Summer season: During summer season many parts of India are scorched with heat. Days are very hot. March, April, and May are the summer months.
• Winter season: The Indian winter is usually mild and enjoyable when compared to other countries of the world on the same latitude. In our state, we have vegetables and fruits that grow in different landscapes during this season.
• Rainy season: During this season the north east monsoon and the south west monsoon bring the rainfall to most parts of the country

Influence of seasons on Human:

• Our lifestyle changes according to the climate. In summer, we like to drink tender coconut, fruit juice, ice apple (nungu) and cold beverages. In winter, we like to have hot, steaming food. In rainy season, we use raincoat, gum boots and umbrellas.

Influence of seasons on Animals:

• Winters are extreme in polar region. In Arctic, animals like whales move from North America to the coastal region of Gulf of California before winter starts to escape from the harsh weather. Similarly birds like arctic fern move in flocks to places where the weather condition is suitable. This movement is called migration. Polar Regions remain frozen in winter. In the extreme cold condition food is scarce. So the polar bears undergo long winter sleep called

Eclipse:

• Eclipse is an astronomical event that occurs when one celestial object moves into the shadow of another.
• The Solar Eclipse: When the moon comes between the sun and the earth the shadow of the moon falls on the earth. People who are in that part of the earth cannot see the sun. This is called solar eclipse. This can occur only on new moon day.
• Lunar Eclipse: A lunar eclipse occurs when the earth blocks the sunrays from reaching the moon. This can occur when the earth comes between the sun and the moon; a lunar eclipse can occur only on a full moon day.

Some interesting facts:

• Parts of North America and Europe, the temperature in winter can be as low as minus 50°C [ice everywhere]. The ideal room temperature is 25°C .The wettest place on the earth is in India, at a place called Mawsynram it receives 12 meters of rainfall every year. The world’s driest place is in Chile, the Atacama Desert.

Representations:

A Globe:

• A globe is a small model of the Earth which gives accurate picture of the Earth’s surface for general reference. It shows us the oceans, seas and continents of the Earth on a small scale. Look at a globe. It is a spherical ball that spins round a rod with two ends. The earth rotates on the axis is called the North Pole and the southernmost point is called the South Pole.

Map:

• Another representation of the earth is a Map. A book of maps is called atlas

Different types of Maps:

• Relief Maps – Show the physical features of the world.
• Political Maps – Show countries, states, Districts, Capital etc
• Climate Maps – Show the different types of climate in the world
• Minerals – Show the minerals and the places they are found
• Transport Maps – Show the location of places and the routes to them
• Agriculture – Show the different crops and the regions they grow

Latitudes

• In the map, some imaginary lines are drawn horizontally and vertically. The horizonatal lines are called latitudes and the vertical lines are called longtitudes.
• Latitudes are ‘imaginary circles running from east to west. One such imaginary line of latitude is the Equator. The Equator divides the earth into two equal halves known as hemispheres. The northern part of the earth above the equator is known as the Northern Hemisphere. The southern part of the earth below the equator is known as the Southern Hemisphere. Latitudes are measured with the Unit “degree”. Latitudes are also called parallels.

Important Latitudes of the Earth:

• The Arctic circle 66 ½ ⁰ N
• The Tropic of Cancer 23 ½ ⁰ N
• Equator 0°
• The Tropic of Capricorn 23 ½ °S
• The Antarctic Circle at 66 ½ ⁰ S

Longitudes:

• Besides latitude there are also circular lines running through the North Pole and the South are called Longitudes or Meridians. The central longitude divides the earth into the Eastern Hemisphere and the Western Hemisphere known as the Prime Meridian. The Prime meridian runs through the Royal Observatory at Greenwich in London in the United Kingdom. It is also known as the Greenwich Meridian which helps us in calculating the time.
• The countries to the east of the Prime Meridian will face the sun first. Gradually, as the earth moves, the countries in the western Hemisphere will face the sun. That’s why the countries like Japan face the sun first and America faces the sun Last. The time at Greenwich is observed as the mean time and hence it is called the Greenwich Mean Time. Local time of a particular country can be calculated based on the GMT.
• Latitudes and Longitudes help us to define the location of any place in the world. Latitudes and Longitudes intersect each other at right angles forming a Grid. This network is helpful in locating the different- places on the map (or) the globe.
• India is located to the east of the Prime Meridian and it is the seventh largest country in the world.

Different Zones of the Earth:

• The earth is like a ball tilted on an axis. Therefore when the earth goes round the sun it is found that direct rays of the sun fall on the equator. At this time, the distance of sun is closest to the Earth. Away from the equator on the other latitudes the rays of the sun are slanting. Thus we have different zones of the Earth.
• The Torrid Zone (or) the Tropical zone is the hottest part of the earth.
• The Temperate Zone lies above the Torrid Zone. It receives slanting rays so it is cooler.
• The Frigid Zone lies around the poles. They receive very little slanting rays for half of the year; for another half of the year received no light at all. This is a very cold zone.

Weather and Climate:

• There is a constant change in the atmosphere that surrounds the Earth. The changes in a particular area make the weather of a place. In other words weather is the condition of the atmosphere at a particular place and time. It may change from day to day, time to time and place to place.
• Climate is the average weather condition of a place over a long period of time. Climate influences things like our clothing, housing, transportation and the food we eat. The factors that influence climate are latitudes, altitude, ocean currents, wind pattern etc. The presence of high mountains, oceans and deserts in an area also affects the climate in and around that area.
• People who study the climate are called climatologists. People who forecast weather are called meteorologists.

Rotation of the Earth:

• Rotation is the movement of the earth on its own axis. It completes one rotation in 24 hours. This is called a solar day. Rotation causes day and night.

Revolution the Earth:

• Revolution is the movement of the earth around the sun on an elliptical orbit. The earth completes one round in 365 and ¼ days. It is because of this revolution of the Earth that we have changing seasons.