9TH STD CBSE SCIENCE BOOK

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Science. NCERT/CBSE class 9 Science book Science. Contain Page. NCERT/ CBSE class 9 Science book Science. CHAP 1. NCERT/CBSE class 9 Science. NCERT Class IX Science Text Book. AglaSem NCERT Solutions Previous « NCERT Class X English: Chapter 2 - Nelson mandela, Long Walk to Freedom. This book is designed as per the Latest CBSE Syllabus for Class 9 Science are designed to cover the whole CBSE syllabus. Class 9 Science NCERT book.


9th Std Cbse Science Book

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Free PDF Download of NCERT chapter-wise solutions for class 9 Science solved by expert teachers from latest edition books and as per NCERT (CBSE). in the CBSE Class 9 Science syllabus. Students studying in class 9 are required to solve the exercise questions included in the NCERT Science Book Class 9. The CBSE class 9 science syllabus, sample papers and question papers are NCERT Text Book For Class IX Mathematics. 2. Science. NCERT Textbook.

We all can consider people around us. They all are having different types nose, different colours of eyes. These differences are among human beings. These differences become more if we move from human beings to monkeys, and increases more if we mover from human beings to fish. The living world is diverse in many ways. This different variety of life around us has evolved on the earth over millions of years. However, we do not have more than a tiny fraction of this time to try and understand all these living organisms, so we cannot look at them one by one.

Instead, we look for similarities among the organisms, which will allow us to put them into different classes and then study different classes or groups as a whole. Different diverse groups can be created based on certain characteristics.

Attempts at classifying living things into groups have been made since time immemorial. The characteristics of body design used for classification of plants will be very different from those important for classifying animals.

This is because the basic designs are different, based on the need to make their own food plants , or acquire it animals.

Therefore, these design features having a skeleton, for example are to be used to make sub-groups, rather than making broad groups. Classification of life forms will be closely related to their evolution. All living organisms are divided on the above bases into five kingdoms, namely Monera, Protista, Fungi, Plantae and Animalia. Plantae and Animalia are further divided into subdivisions on the basis of increasing complexity of body organisation.

Plants are divided into five groups: Thallophytes, Bryophytes, Pteridophytes, Gymnosperms and Angiosperms. The binomial nomenclature makes for a uniform way of identification of the vast diversity of life around us. The binomial nomenclature is made up of two words — a generic name and a specific name.

Motion Motion is defined for movement. If any object is continuously changing its position with time, it is said to be in motion. Examples are, a moving car, a boy running. If any object is not changing its position with time it is said to be in rest. A body may be in rest for one object and in motion for another. Two people sitting in train are in rest with respect to each other. But, they are in motion with some person the train. So, rest or motion is defined for some particular reference point.

Here, we are basically concerned about straight line motion. Distance is total path covered by a person in motion. Speed defined as distance travelled by time taken. Displacement is defined as shortest distance between initial and final distance.

Velocity is defined as displacement by time. After that, concept of uniform and Non-uniform motion is discussed. Uniform motion is defined as when same distance is travelled at same time. The acceleration of an object is the change in velocity per unit time. Uniform and non-uniform motions of objects can be shown through graphs. Distance time and velocity time graph has been discussed. The motion of an object moving at uniform acceleration can be described with the help of equation of motion.

If an object moves in a circular path with uniform speed, its motion is called uniform circular motion. Force and Law of Motion Motion was discussed in previous chapter.

What causes motion? A ball on the ground, when given a small hit, does not move forever.

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This remained the belief until Galileo Galilee and Isaac Newton developed an entirely different approach to understand motion. In force, both magnitude and direction is considered. Concept of balanced and unbalanced force is discussed.

In balanced force, net force is zero, as equal magnitude of force is applied from opposite sides. Net force is zero. In unbalanced force, net force is not equal to zero. For change of state from rest to motion, or motion to rest, or to change velocity of an object, unbalanced force is required. So, this much is the concept of force. 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.

The natural tendency of objects to resist a change in their state of rest or of uniform motion is called inertia. The first law is also known as law of inertia. The law has been explained with several examples. The mass of an object is a measure of its inertia. Its SI unit is kilogram kg. Force of friction always opposes motion of objects. Second law of motion says, The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the force.

The SI unit of force is kg m s —2. This is also known as newton and represented by the symbol N. A force of one newton produces an acceleration of 1 ms —2 on an object of mass 1 kg. The momentum of an object is the product of its mass and velocity and has the same direction as that of the velocity. Its SI unit is kg ms —1 ,also known as Newton. Third law of motion says, To every action, there is an equal and opposite reaction and they act on two different bodies.

In an isolated system where there is no external force , the total momentum remains conserved. Gravitation In previous chapter it is discussed force is required for motion.

We have learnt that a force is needed to change the speed or the direction of motion of an object. We always observe that an object dropped from a height falls towards the earth.

We know that all the planets go around the Sun. The moon goes around the earth.

In all these cases, there must be some force acting on the objects, the planets and on the moon. Sir Isaac Newton figured out that force responsible for all these things is Gradational force.

The gravitational force is force acting between two bodies due to their masses. The chapter starts with the concept of gravitation. After that Universal Law of Gravitation was discussed. The gravitational force acting between two bodies is directly proportional to the product of their masses and inversely proportional to the square of distance between them.

The gravitational force is responsible for motion of planets, free fall of any object, tides in oceans. Whenever objects fall towards the earth under this force alone, we say that the objects are in free fall. If two bodies are thrown from same height, irrespective of their masses both of them will fall together with same acceleration due to gravity g.

Equations of motions can be written accordingly. The concept of mass and weight is discussed. Mass of an object is the measure of its inertia. Weight is gravitational force acting on the body. For body of mass m, weight is mg, where g is acceleration due to gravity. So, value of g will vary with that. Moon is having lesser mass and radius than earth. It is important to understand the difference between mass and weight.

Thrust and Pressure are discussed after that. Thrust is vertical force acting on any object. The concept has been explained in chapter with suitable examples.

Thrust is also created by liquids kept on the base and walls of the container in which they are enclosed. Pressure exerted in any confined mass of fluid is transmitted undiminished in all directions. When an object is placed in the liquid, upward force is experienced on it. The force is Buoyant force. The magnitude of this buoyant force depends on the density of the fluid. Relative density is the ratio of density of that object with respect of density of water.

If it is more than 1, the object will sink in water, otherwise it will float. Work and Energy In previous chapter, we have discussed about force, motion and gravitation.

We need energy for other activities like playing, singing, reading, writing, thinking, jumping, cycling and running. Activities that are strenuous require more energy. Work and energy are related. Both are explained one by one. First, the concept of work is to be understood. Definition of work done is different from day to day life. Work is defined for a force. Work is defined as force multiplied by displacement. If there is no displacement, we say there is no work.

The concept is dealt here. SI unit of work done is joule. It is important, in displacement direction is considered. If the force and displacement are in same direction the work done is positive. If force and work done are perpendicular to each other, work done is zero.

If displacement is made in opposite direction of force applied, the work done is in opposite direction. Energy is defined as capacity to do the work. The Sun is the biggest natural source of energy to us. How does an object with energy do work? An object that possesses energy can exert a force on another object. When this happens, energy is transferred from the former to the latter. The second object may move as it receives energy and therefore do some work.

The unit of energy is, therefore, the same as that of work, that is, joule J. Forms of Energy are discussed after that.

Kinetic energy is energy possessed by a body in motion. Kinetic energy of a body moving with a certain velocity is equal to the work done on it to make it acquire that velocity. Potential energy is defined as energy stored in an object. For example, when an spring is contracted or expanded, some energy is stored in it. The spring comes back to its original position when left using energy stored in it. Similarly, if some object is kept at some height, gravitational potential energy is stored in it.

We can say, the potential energy possessed by the object is the energy present in it by virtue of its position or configuration.

Energy is conserved. If an object is kept at height it gains potential energy, when dropped its potential energy started converting into kinetic energy. At any point of time during free fall, the net energy is same. That is some of potential energy and kinetic energy will remain always same. This is law of conservation of energy.

Rate of doing work is known as Power. The SI unit of power is watt. The energy used in one hour at the rate of 1kW is called 1 kW h. It is also known as commercial unit of energy. Sound Sound is a form of energy which produces a sensation of hearing in our ears. Different types of sound we hear in our day to day to life. These are the sounds of bird, horn of cars, children crying around and many more. There are also other forms of energy like mechanical energy, light energy etc.

We know that energy is conserved and can change its form. When we clap, the mechanical energy is converted into sound energy. 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.

NCERT Solutions For Class 9 Science

Sound cannot travel in vacuum. The change in density from one maximum value to the minimum value and again to the maximum value makes one complete oscillation. The time taken by the wave for one complete oscillation of the density or pressure of the medium is called the time period, T. The number of complete oscillations per unit time is called the frequency. The speed of sound depends primarily on the nature and the temperature of the transmitting medium. The law of reflection of sound states that the directions in which the sound is incident and reflected make equal angles with the normal to the reflecting surface at the point of incidence and the three lie in the same plane.

For hearing a distinct sound, the time interval between the original sound and the reflected one must be at least 0. The persistence of sound in an auditorium is the result of repeated reflections of sound and is called reverberation. Sound properties such as pitch, loudness and quality are determined by the corresponding wave properties. Loudness is a physiological response of the ear to the intensity of sound.

The amount of sound energy passing each second through unit area is called the intensity of sound. The audible range of hearing for average human beings is in the frequency range of 20 Hz — 20 kHz. Ultrasound has many medical and industrial applications. The SONAR technique is used to determine the depth of the sea and to locate under water hills, valleys, submarines, icebergs, sunken ships etc. Why do we Fall Ill? Health and disease in human communities are very complex issues.

In our organs or tissues, there are various specialised activities going on — the heart is beating, the lungs are breathing, the kidney is filtering urine, the brain is thinking. All these activities are interconnected. For healthy well-being, it is very important every organ of human beings should work properly. In this chapter the term health is defined and explained. Health is a state of physical, mental and social well-being. Diseases are conditions in which there is lack of physical, mental and social well-being.

Different types of diseases are explained. Diseases are classified as acute or chronic, depending on their duration.

Disease may be due to infectious or non-infectious causes. Infectious agents belong to different categories of organisms. These organisms may be unicellular and microscopic or multicellular. The category to which a disease-causing organism belongs decides the type of treatment. Infectious agents are spread through air, water, physical contact or vectors. It is important to note down. Prevention of disease is more desirable than its successful treatment. Infectious diseases can be prevented by public health hygiene measures that reduce exposure to infectious agents.

Infectious diseases can also be prevented by using immunisation. Effective prevention of infectious diseases in the community requires that everyone should have access to public hygiene and immunisation.

Natural Resources The resources available on the Earth and the energy from the Sun are necessary to meet the basic requirements of all life-forms on the Earth. These are the land, the water and the air. All these resources are discussed one by one. Air is a mixture of many gases like nitrogen, oxygen, carbon dioxide and water vapour.

Role of atmosphere as climate controller is discussed. After that, wind formation is discussed.

Movement of air form land to sea and sea to land is discussed. Uneven heating of air over land and water-bodies causes winds. Evaporation of water from water-bodies and subsequent condensation give us rain. All chapter and their exercises solutions along with intext questions solutions are free to download and keep it to use offline. NCERT Books and Main points of the chapters are given under the head of chapter name that must be covered after the completion of chapter.

Prepare for an annual exam based on entire syllabus of CBSE for Is matter around us pure? Separation of components of mixture and their application. Physical and chemical changes, Some basic idea about elements and compounds. Writing chemical formula of simple compounds, molecular mass and mole concepts, formula unit mass. The fundamental unit of life — Cell: Different type of tissues: Animal tissues — Epithelial tissue, Connective tissue, Muscular tissue and Nervous tissue.

In diversity in living organisms there are attempts made by scientist.

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Aristotle — Classification of animals according to their living on land, water or air. A eukaryotic cell has membrane-bound organelles, including a nucleus.

Biologists, such as Ernst Haeckel , Robert Whittaker and Carl Woese have tried to classify all living organisms into broad categories, called kingdoms.

Describing motion in a straight line — uniform motion and non-uniform motions. Acceleration — Rate of change of velocity and average speed and velocity. Graphical representation of motion, derivation of three equation of motion and numerical based on equation of motion. Concepts on uniform circular motion. In chapter force and laws of motion , there is balance and unbalance forces.

Second law of motion — momentum, rate of change of momentum.

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Third law of motion — for every action there is equal and opposite reaction, applications on first, second and third laws of motion. Conservation of momentum and their application in daily life. Relation between work and energy , situation when work is done. Scientific conception of work, work done by constant force. Application on kinetic and potential energy, energy of an object at a height.

Law of conservation of energy and rate of doing work power.Relative experiments has been discussed. Class 10th. Sample Paper 2. Properties of a compound are different from its constituent elements, whereas a mixture shows the properties of its constituting elements or compounds.

All these activities are interconnected. In diversity in living organisms there are attempts made by scientist. A House Is Not a Home.

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