Class 09 NCERT Chapters

Rights are reasonable claims of persons recognised by society and sanctioned by law. Rights are necessary for the very sustenance of a democracy.

President is the head of the state and is the highest formal authority in the country. Prime Minister is the head of the government and actually exercises all governmental powers. He takes most of the decisions in the Cabinet meetings.

Elections take place regularly in any democracy. Elections is a mechanism by which people can choose their representatives at regular intervals and change them if they wish to do so.

The constitution of a country is a set of written rules that are accepted by all people living together in a country. Constitution is the supreme law that determines the relationship among people living in a territory (called citizens) and also the relationship between the people and government.

Democracy is a form of government in which the rulers are elected by the people. In a democracy the final decision-making power must rest with those elected by the people.

In this chapter you will read about nomadic pastoralists. Nomads are people who do not live in one place but move from one area to another to earn their living. In many parts of India we can see nomadic pastoralists on the move with their herds of goats and sheep, or camels and cattle.

A lot of this diversity is fast disappearing. Between 1700 and 1995, the period of industrialisation, 13.9 million sq km of forest or 9.3 per cent of the world’s total area was cleared for industrial uses, cultivation, pastures and fuelwood.

In the spring of 1945, a little eleven-year-old German boy called Helmuth was lying in bed when he overheard his parents discussing something in serious tones.

The French Revolution opened up the possibility of creating a dramatic change in the way in which society was structured. Before the eighteenth century society was broadly divided into estates and orders and it was the aristocracy and church which controlled economic and social power.

On the morning of 14 July 1789, the city of Paris was in a state of alarm. The king had commanded troops to move into the city. Rumours spread that he would soon order the army to open fire upon the citizens.

Food security of a nation is ensured if all of its citizens have enough nutritious food available, all persons have the capacity to buy food of acceptable quality and there is no barrier on access to food.

Poverty has many dimensions. Normally, this is measured through the concept of poverty line. A common method used to measure poverty is based on the income or consumption levels. Through this concept we analysed main global and national trends in poverty.

Inputs like education and health helped in making people an asset for the economy. Investment in human capital (through education, training, medical care) yields a return just like investment in physical capital.

Farming is the main production activity in the village. Over the years there have been many important changes in the way farming is practiced. These have allowed the farmers to produce more crops from the same amount of land.

The people are important to develop the economy and the society. The people make and use resources and are themselves resources with varying quality. Coal is but a piece of rock, until people were able to invent technology to obtain it and make it ‘resource’. Natural events, like a flood or a Tsunami, becomes a ‘disaster’ only when they affect a crowded village or a town.

India is one of the 12 mega bio-diversity countries of the world. With about 47,000 plant species India occupies tenth place in the world and fourth in Asia in plant diversity. There are about 15,000 flowering plants in India, which account for 6 per cent in the world’s total number of flowering plants.

Climate refers to the sum total of weather conditions and variations over a large area for a long period of time (more than thirty years). Weather refers to the state of the atmosphere over an area at any point of time. The elements of weather and climate are the same - temperature, atmospheric pressure, wind, humidity and precipitation.

The term drainage describes the river system of an area. Small streams flowing from different directions come together to form the main river, which ultimately drains into a large water body such as a lake or a sea or an ocean. The area drained by a single river system is called a drainage basin.

India is a large landmass formed during different geological periods which has influenced her relief. Besides geological formations, a number of processes, such as weathering, erosion and deposition, have created and modified the relief to its present form. Earth scientists have attempted to explain the formation of physical features with the help of some theories based on certain evidences.

India is one of the ancient civilisations in the world. It has achieved multi-faceted socio-economic progress during the last five decades. It has moved forward displaying remarkable progress in the field of agriculture, industry, technology and overall economic development. India has also contributed significantly to the making of world history.

There are several nutrients essential for crops. Of these, some are required in large quantities and are known as macro-nutrients whereas rest of the nutrients are required in small quantities and are known as micro-nutrients. Manure and fertilizers are the main sources of nutrient supply to crops.

Sound is produced due to vibration of different objects. Sound travels as a longitudinal wave through a material medium. Sound travels as successive compressions and rarefactions in the medium. In sound propagation, it is the energy of the sound that travels and not the particles of the medium. Sound cannot travel in vacuum.

Work done on an object is defined as the magnitude of the force multiplied by the distance moved by the object in the direction of the applied force. The unit of work is joule: 1 joule = 1 newton × 1 metre.

The law of gravitation states that the force of attraction between any two objects is proportional to the product of their masses and inversely proportional to the square of the distance between them. The law applies to objects anywhere in the universe. Such a law is said to be universal.

First law of motion: An object continues to be in a state of rest or of uniform motion along a straight line unless acted upon by an unbalanced force.

Motion is a change of position. It can be described in terms of the distance moved or the displacement. The motion of an object could be uniform or non-uniform depending on whether its velocity is constant or changing.

Tissue is a group of cells similar in structure and function. Plant tissues are of two main types - meristematic and permanent.

The fundamental organisational unit of life is the cell. Cells are enclosed by a plasma membrane composed of lipids and proteins. The cell membrane is an active part of the cell. It regulates the movement of materials between the ordered interior of the cell and the outer environment.

Credit for the discovery of electron and proton goes to J.J.Thomson and E.Goldstein, respectively. J.J. Thomson proposed that electrons are embedded in a positive sphere. Rutherford’s alpha-particle scattering experiment led to the discovery of the atomic nucleus.

During a chemical reaction, the sum of the masses of the reactants and products remains unchanged. This is known as the Law of Conservation of Mass.

A mixture contains more than one substance (element or compound) mixed in any proportion. Mixtures can be separated into pure substances using appropriate separation techniques.

Matter is made up of small particles. The matter exists in three states - solid, liquid and gas. The forces of attraction between the particles are maximum in solids, intermediate in liquids and minimum in gases.

Facts or figures, collected with a definite purpose, are called data. Statistics is the area of study dealing with the presentation, analysis and interpretation of data. How data can be presented graphically in the form of bar graphs, histograms and frequency polygons.

So far, you have been dealing with figures that can be easily drawn on our notebooks or blackboards. These are called plane figures. It would be interesting to see what happens if you cut out many of these plane figures of the same shape and size from cardboard sheet and stack them up in a vertical pile. By this process, you obtain some solid figures such as a cuboid, a cylinder, cube, and sphere.

The formula given by Heron about the area of a triangle, is also known as Hero's formula. This formula is helpful where it is not possible to find the height of the triangle easily.

A circle is the collection of all points in a plane, which are equidistant from a fixed point in the plane.

Sum of the angles of a quadrilateral is 360°. A diagonal of a parallelogram divides it into two congruent triangles.

Two figures are congruent, if they are of the same shape and of the same size. Two circles of the same radii are congruent. Two squares of the same sides are congruent.

If a ray stands on a line, then the sum of the two adjacent angles so formed is 180° and vice-versa. This property is called as the Linear pair axiom. If two lines intersect each other, then the vertically opposite angles are equal.

Though Euclid defined a point, a line, and a plane, the definitions are not accepted by mathematicians. Therefore, these terms are now taken as undefined. Axioms or postulates are the assumptions which are obvious universal truths. They are not proved.

An equation of the form ax + by + c = 0, where a, b and c are real numbers, such that a and b are not both zero, is called a linear equation in two variables. A linear equation in two variables has infinitely many solutions.

To locate the position of an object or a point in a plane, we require two perpendicular lines. One of them is horizontal, and the other is vertical. The plane is called the Cartesian, or coordinate plane and the lines are called the coordinate axes.

A polynomial p(x) in one variable x is an algebraic expression in x of the form

p(x) = a_nxⁿ + a_n-1x^n-1 + . . . + a₂x²+ a₁x + a₀,

where a₀, a₁, a₂, . . ., an are constants and a_n ≠ 0.

A number r is called a rational number, if it can be written in the form p/q, where p and q are integers and q ≠ 0. A number s is called a irrational number, if it cannot be written in the form p/q, where p and q are integers and q ≠ 0.

What induced the beggar, Lushkoff, to change his ways? Let’s read and find out.

This story reflects the challenges of being a teenager, and the problems of growing up. How does the author overcome his problems?

It is autumn. The wind is blowing hard and it is raining heavily. All the leaves on an ivy creeper have fallen, except one. Why doesn’t the last leaf fall?

The cyclone that hit Orissa in October 1999 killed thousands of people and devastated hundreds of villages. For two dreadful nights Prashant, a young man, was marooned on the roof of a house. On the third day he decided to go to his village. Did he find his family?

The Happy Prince was a beautiful statue. He was covered with gold, he had sapphires for eyes, and a ruby in his sword. Why did he want to part with all the gold that he had, and his precious stones?

It is believed that fools are so dangerous that only very wise people can manage them. Who are the fools in this story? What happens to them?