The Chapter “The Earth” discussed in this post is taken from Let’s Look Around and Learn Environmental Studies for students of Class 5 from JKBOSE. The post is about The Earth Class 5th EVS Chapter 11 Summary Notes. You have already read about Question Answers of Chapter the Earth in the previous post. Let’s not waste much time and get started:
The Earth Class 5th EVS Chapter 11 Summary Notes
Introduction
The chapter describes the formation of the earth, and its composition briefly. It also describes the formation of day and nights and the change of seasons briefly. It also describes eclipses briefly. The earth is a unique planet because it has an atmosphere and water and it is the only planet that has life. The study of the earth is called Geology and sciences that deal with the earth are known as Earth Sciences.
Formation of the Earth
Earlier it was thought that the earth developed from a rotating body of hot gases in space. These gases cooled down and form the earth and other heavenly bodies.
In about 1900, it was suggested that the earth developed out of material from the sun. It is believed that the earth was fiery hot during the early part of its formation. As millions of years went by, the earth grew cooler and a thin crust is formed on its surface which sealed in the heat.
Inside the Earth
The earth has three layers in it:
1. Crust 2. Mantle 3. Core.
- Crust: It is the thin outermost layer of the earth. The thickness of the crust varies from place to place. It is about 35 to 60 kilometres under the continents and is very thin only about 6 kilometres under the sea.
- Mantle: The region between the crust and core of the earth is called the mantle. It is about 2900 km thick; the mantle is made up of semi-molten hot rocks. The temperature and pressure in the mantle are lower than the core.
- Core: The innermost part of the earth is called the core. The core is made up of iron and nickel. The outer region of the core has metals present in the molten state. The inner region of the core is a solid ball.
How Mountains are Formed?
Mountains are formed by the movement in the earth’s crust and it takes millions of years to form. Sometimes, the earth’s crust gets squeezed and forms fold mountains.
Block Mountains: Block mountains are formed when the earth’s crust splits and one side is pushed up.
Dome Mountains: Dome mountains are formed when melted rock below the earth’s crust slowly forces the land upwards.
Volcano
Volcanic eruption is one of the ways through which mountains are formed. In volcanic eruption hot, liquid rock is forced to the surface of the earth through the cracks in the rocks. If the molten lava comes to the surface, it may flow out, or be blown out.
The melted rock, steam and ashes that are forced through a hole in the surface, may form a mountain called a volcano.
Earthquake
Earthquakes take place when large masses of rock slip past each other suddenly. When an earthquake takes place, great trembling and vibrations are felt. Sometimes these shocks are so strong that they destroy buildings and cause great damage. Some major destructive earthquakes which took place on earth are:
In 1923 in Japan, 1,50,000 lives are lost and about 5,70, 000 buildings collapsed.
In 1988 in Armenia, 25,000 people got killed and several towns and cities were buried.
In 2001 over 90% of the buildings of Bhuj city of Gujarat state in India were damaged.
In 2005 J&K suffered a major earthquake and huge damage was done.
The shocks of earthquakes may be recorded on an instrument called a Seismograph.
The Movements of the Earth
There are two types of movements shown by the earth.
1. Rotation. 2. Revolution
- Rotation: The spinning of the earth on its axis is called the rotation of the earth. The earth takes 24 hours to complete one rotation on its axis. It spins very fast on its axis but the speed of rotation varies at different places.
At the poles, the earth spins at speed of 400 km/h while at the equator it spins at speed of 1600 km/h. It is because the part of the earth near the equator has to make a bigger round.
Day and Night
The rotation of the earth is responsible for the formation of day and night. At any point, the time the half of the earth faces the sun while the other half remains at the backside. The half of the earth that faces the sun has day while the half that remains away from the sun is night.
As the earth rotates, the part of the earth facing the sun went to the back side and experiences night while the part on the backside came in front of the sun and has a day on it.
The earth rotates in the direction from west to east. Therefore, it seems that the sun rises in the east and sets in the west.
- Revolution: The movement of the earth on its axis around the sun is called the revolution of the earth. The earth takes 365 days and 6 hours to complete one revolution. It is called a solar year.
Seasons
The tilt of the earth’s axis and the revolution of the earth around the sun are the two factors responsible for the revolution of the earth.
The sun’s rays fall directly on the Equator throughout the year and so it experiences summer throughout the year and days and nights are equal in the equator region of the earth.
There are four seasons formed due to the revolution and tilted axis of the earth. These are Summer, Winter, Spring and Autumn.
Effects of Seasons on Life
Both Plants and Animals are affected by changing seasons and they adapt themselves to the surrounding climate.
Summer is very hot and we do not like to go outdoors in summer. In summer, we like to spend our time indoors. We like to wear thin light coloured cotton clothes in summer because they absorb less heat and keep it away from our bodies.
We use electric fans, desert coolers and air-conditioners to make our homes cool. We also like to drink plenty of water, sharbat and other cold drinks.
Winter is very cold and we feel more energetic and like to spend our time outdoors sitting and playing in the sun. In winter, we use dark-coloured clothes, blankets and quilts to protect ourselves from severe cold. These clothes protect body heat from escaping.
We use electric heaters and fireplaces to keep our houses warm. We use drinks like hot milk, tea or coffee and consume plenty of nuts to remain warm.
Other animals like human beings are also affected by seasons. Animals having thick fur or hair can withstand the cold while other animals like frogs and snakes, burrow themselves underground to keep themselves warm. They undertake “winter sleep’ called hibernation. Birds migrate from a colder regions to warmer regions to avoid extreme cold.
Plants also respond to the changes in seasons. Many small plants bloom and dry up before summer. During the autumn seasons, plants shed their leaves to protect themselves from approaching winter. Some plants like herbs flower during winters while shrubs and trees mostly flower during summer.
Eclipses
An eclipse is the partial or complete hiding of one heavenly body by another by its shadow. The Revolution of heavenly bodies is responsible for the formation of eclipses because the positions of heavenly bodies keep changing while revolving.
There are two types of eclipses: Solar eclipse and Lunar eclipse.
Solar Eclipse: Solar eclipse is when the moon comes between the earth and the sun. The moon blocks some sunlight from the earth and makes a small shadow on the earth. From this shadow, the sun appears to get covered slowly.
Lunar Eclipse: Lunar eclipse takes place when the earth comes between the sun and the moon. The moon at this time passes through the earth’s shadow.
New Words in the Lesson
Atmosphere: The layer of gases that surrounds a planet.
Axis: Imaginary line through the centre of a rotating object.
Billion: One million million.
Core: The innermost part of the earth.
Crust: The outermost layer of the earth.
Earthquake: Sudden violent movement of the earth’s surface.
Equator: Imaginary line around the earth at an equal distance from the North and the South Pole.
Fiery: Like or consisting of a fire.
Flod: A band of rock layers.
Geology: Scientific study of the earth’s crust.
Lava: Hot liquid rock that comes out of a volcano.
Mantle: The region between the crust and the core of the earth.
Orbit: Path followed by a planet, star, moon, etc., round another body.
Revolution: Movement of the earth around the sun.
Rotation: Spinning of the earth on its axis.
Seismograph: Instrument for detecting earthquakes and recording how strong they are and how long they last.
Space: Universe beyond the earth’s atmosphere in which all other planets and stars exist.
Volcano: Mountain or hill with an opening or openings through which lava, etc., comes up from below the earth’s surface.
That’s all we have about The Earth Class 5th EVS Chapter 11 Summary Notes. Hope you got your answers. Do share your views about this post in the comment section.
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