Class-IX-I.I.T.Foundation

IX I.I.T. Foundation & Science Olympiad Curriculum Chapter as per NCERT Text Book

Topic

Physics -IX 1. Motion

2. Force and Laws of Motion

3. Gravitation

4. Work and Energy 5. Sound

Introduction to Motion Graphical Representation of Motion Force First Law of Motion Momentum and Second Law of Motion Third Law of Motion Kepler's Law of Gravitation Universal Law of Gravitation Thrust and Pressure Archimedes Principles and Buoyancy Work Energy Production and Propagation of Sound Reflection of Sound

Chemistry -IX 1. Matter in our Surroundings 2. Is Matter Around Us Pure? 3. Atoms and Molecules 4. Structure of The Atom

States of Matter Inter Conversion of States of Matter Types of Substances Types of Mixtures Methods of Seperation of Mixtures Atoms and Molecules Mole Concept Atomic Models Structure of an Atom

Biology -IX 1. The Fundamental Unit of Life 2. Tissues 3. Diversity in Living Organisms 4. Why Do We Fall Ill? 5. Natural Resources 6.Improvement in Food Resources

Introduction to Cell Cell Structure Plant Tissues Animal Tissues Classification of Living Organisms The Plant Kingdom The Animal Kingdom Diseases Transmission of Diseases Natural Resources Biogeochemical Cycles Improvement of Crop Resources Animal Husbandry

IX I.I.T. Foundation & Science Olympiad Curriculum

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IX I.I.T. Foundation & Science Olympiad Physics Chapter Chapter Notes Chapter As Per NCERT Text Book

Topic

Introduction to Motion 1. Motion

Graphical Representation of Motion Force First Law of Motion 2. Force and Laws of Motion

Momentum and Second Law of Motion Third Law of Motion Kepler's Law of Gravitation Universal Law of Gravitation 3. Gravitation

Thrust and Pressure Archimedes Principles and Buoyancy Work 4. Work and Energy

Energy Production and Propagation of Sound 5. Sound

Reflection of Sound

IX I.I.T. Foundation & Science Olympiad Physics Chapter Notes

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Motion Introduction to Motion

If a body does not change its position with respect to time and the surroundings, it is said to be at rest and else it is said to be in motion . Motion of objects can take place along one direction, two directions or three directions at a time. If an object moves along a straight path it is said to be linear or one-dimensional motion. If an object moves along two directions at a time like that of a ball hit for a sixer in a cricket field, it is two-dimensional . The haphazard motion of a honey bee can be three-dimensional. The change in position of an object is termed displacement . It requires both direction and magnitude for its complete description and hence such physical quantities are called a vectors. The length of the path covered by a moving body is its distance and is independent of direction. Thus, such physical quantities are called scalars. The rate of displacement of a body is its velocity and is measured in metre per second in international units. If a body has equal displacements in equal intervals of time however smaller the intervals may be, it is said to be moving with uniform velocity. If the body is moving such that it has unequal displacements in equal intervals or equal displacements in unequal intervals of time, it is said to be moving with non-uniform velocity. The ratio of total displacement to total time taken by the body gives its average velocity. The velocity of a body at a given instant is its instantaneous velocity. The rate of distance covered by a body is its speed and is measured in metre per second in international units. If a body covers equal distances in equal intervals of time however small the IX I.I.T. Foundation & Science Olympiad Physics Chapter Notes

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intervals may be, it has uniform speed . If a body covers unequal distances in equal intervals or equal distances in unequal intervals then it is said be moving with non-uniform speed. The ratio of total distance to total time taken by the body gives its average speed. The speed of a body at a given instant is its instantaneous speed . The rate of change in velocity is termed acceleration and is measured in metre per second square in the international system of units. The negative acceleration is termed retardation.

Graphical Representation of Motion

A graph is a pictorial representation of the relation between two sets of data of which one set is of dependent variables and the other set is of independent variables. In a displacement-time graph, displacement is a dependent quantity, taken on the Y-axis and time is taken on the X -axis, as it is independent. If the position of an object changes with time, it is said to be in motion . If an object has equal displacements in equal intervals of time then the graph is a straight line inclined with the X-axis which represents uniform motion of the object. If the graph is a curve it represents non-uniform motion. The slope of displacement-time graph gives velocity of the object. However if the graph is a straight line parallel to the X-axis, the object is said to be at rest. In a velocity-time graph, velocity is a dependent quantity, taken on the Y-axis and time, the independent quantity is taken on the X-axis. If the graph is a straight line parallel to the X-axis then slope of the graph is zero and the object will have uniform velocity, and for uniform velocity the acceleration is zero, instead if the graph is a curve it represents non-uniform velocity and the slope of the graph gives acceleration of the object. The velocity at any instant i nstant


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instantaneous velocity. A positive slope of velocity-time graph gives of time is called instantaneous

acceleration and a negative slope gives deceleration or retardation of the object. Again if the slope of the velocity-time graph is constant, than the acceleration is termed as uniform acceleration, else if the slope is changing than it is non-uniform acceleration. The area

enclosed between the velocity-time graph and time axis gives the displacement of the object. Depending on the velocity, the shape of the area enclosed may be a triangle or a rectangle. For an object moving with uniform acceleration, we have the following equations of motion, v = u + at ; s= ut + at2 ; v2 - u2 = 2as ;

If an object moves along a straight line path, it is in a linear motion. If an object covers equal angular displacements in equal intervals of time then it is said to be in uniform circular motion . If an object repeats its path again and again after regular intervals of time than it is in periodic motion.


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Force and Laws of Motion Force

If an object does not change its position with respect to time and the surroundings, it is said to be at rest, else it is said to be in motion . Force is that which changes or tries to change the state of rest or of motion of an object by a push or pull. The magnitude of force on an object is given by the product of the mass of the object (m) and its acceleration (a). Mathematically it is expressed by the equation, F = ma. CGS unit of force is dyne and the SI unit is newton (N). The line along which a force acts on an object is called the line of action of the force. The point where the force acts on an object is called the point of application of the force. When a number of forces act simultaneously on an object then their equivalent is the net force on an object. If the net force is zero the forces are said to be balanced which results in zero acceleration, else the forces are said to be unbalanced which results in acceleration of the object. The force that opposes the relative motion between the surfaces of two objects in contact and acts along the surfaces in contact is called the force of friction or simply friction. If a body is either at rest or in uniform motion along a straight line path, then it is said to be in its natural state. According to the concepts developed by Galileo Galilei and Isaac Newton, if a body is either at rest or in uniform motion along a straight line path, then it is said to be in its natural state.

When the forces acting on an object are balanced, the net force or the resultant force acting on the body is zero. In such cases, the body continues to be in its natural state. If all the forces IX I.I.T. Foundation & Science Olympiad Physics Chapter Notes

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acting on a body result in an unbalanced force, then the unbalanced force can accelerate the body. It means that a net force or resulting force acting on a body can either change the magnitude of its velocity or change the direction of its velocity.

For example, when many forces are known to be acting on a body, and the body is found to be at rest, then we can conclude that the net force acting on the body is zero. Sometimes, balanced forces can cause a change in the shape of a body. The SI unit for force is the "newton," and its CGS unit is the "dyne". How many dynes are equal to one newton? One newton is (kilogram - metre per second square). When we replace kilogram with thousand grams, and metre with hundred centimetres, then one newton is equal to ten to the power five into (gram - centimetre per second square). However, gram-centimetre per second square is known as "dyne". Therefore, one newton is equal to ten to the power five dynes.

First Law of Motion

An object by its own does not change its state state of rest or uniform motion. This inability of any object to change its state is called inertia. Newton's first law of motion gives the concept of inertia and force. According to the law, any object in the universe remains in its state of rest or IX I.I.T. Foundation & Science Olympiad Physics Chapter Notes

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uniform motion. Inertia is of three types, namely Inertia of rest, Inertia of motion and Inertia of direction. Mass of an object is an intrinsic property of matter. Mass is a measure of inertia of an object. If an object does not change its position with respect to time and the surroundings, it is said to be at rest and else it is said to be in motion . The rate of change in position of an object is velocity. If an object covers equal displacements in equal intervals of time, the motion is called uniform motion, else it is non-uniform motion. Mass and Inertia

According to Newton's first law of motion, inertia is the natural tendency of an object to resist any change in its natural state of motion. Can we measure the inertia of an object? What is the SI unit for inertia?

Inertia of an object is not a physical quantity, and hence, we can't measure it directly. Therefore, it does not have any unit. The mass of a body is the measure of its inertia. It means that heavier and more massive bodies offer more inertia than lighter and less massive bodies. If a large body is at rest, then a large force is required to put it in motion. For example, even a small child can push a toy car. However, An adult also can't push a loaded vehicle forward. This is the reason why kicking a football f ootball is a pleasure, while kicking a large stone is very painful.


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Intro to First Law of Motion Galileo experimentally proved that objects in motion move with constant speed when there is

no force acting on it. He performed many experiments with inclined planes. He noted that when a sphere is rolling down an inclined plane, its speed increases because of the gravitational pull acting on it. The speed of the sphere decreases as it climbs an inclined plane. When two inclined planes are placed side by side, and the sphere that rolls down the first inclined plane is made to climb the second inclined plane, it comes to rest after reaching a certain height. According to Galileo, if the force acting on the sphere is only gravitational force, then the height reached by the sphere must be equal to the height from which it was rolled. When the inclinations of the two planes are the same, the distance travelled by the sphere while rolling down is equal to the distance travelled by it while climbing up. Now, if the inclination of the second plane is decreased slowly, then the sphere needs to travel over longer distances to reach the same height. If the second plane is made horizontal, then the sphere must travel forever trying to reach the required height.


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This is the case when there is no unbalanced force acting on it. However, in reality, frictional forces bring the sphere to rest after it travels over a finite distance. di stance. After further study, Newton, in his first law of motion , stated that all objects resist a change in their natural state of motion.

This tendency of resisting any change in the natural state of motion is called "inertia".

Momentum and Second Law of Motion

When a cricketer catches a ball he moves his hand back while catching the ball. He does this to reduce the impact, which is the force of the ball on his hand. An object in motion has momentum. Momentum is defined as the product of mass and velocity vel ocity of an object. The momentum at the start of the time interval is i s the initial momentum and at the end of the time interval is the final momentum. The rateof change of momentum of an object is proportional to the applied force. Newton's second law quantifies the force on an object. The magnitude of force is given by the

equation, F = ma, where 'm' is the mass of the object and 'a' is its acceleration. The CGS unit of IX I.I.T. Foundation & Science Olympiad Physics Chapter Notes

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force is dyne and the SI unit is newton (N). A large amount of force acting on an object for a short interval of time is called impulse or impulsive force. Numerically impulse is the product of force and time. Impulse of an object is equal to the change in momentum of the object. Impulse and Impulsive Force

The momentum of an object is the product of its mass and velocity. The force acting on a body causes a change in its momentum. In fact, according to Newton's second law of motion , the rate of change in the momentum of a body is equal to the net external force acting on it. Another useful quantity that we come across is " impulse". "Impulse" is the product of the net external force acting on a body and the time for which the force is acting. If a force "F" acts on a body for "t" seconds, then impulse is equal to "F" into "t". In fact, this is also equal to the change in the momentum of the body. It means that due to the application of force, if the momentum of a body changes from "P" to "P dash", then impulse is equal to "P dash minus P". For the same change in momentum, a small force can be made to act for a long period of time, or a large force can be made to act for a short period of time. A fielder in a cricket match uses the first method while catching the ball. He pulls his hand down along with the ball to decrease the impact of the ball on his hands.


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In a cricket match, when a batsman hits a ball f or a six, he applies a large force on the ball for a very short duration. Such large forces acting for a short time and producing a definite change in momentum are called "impulsive forces".

Third Law of Motion


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For every action, there is an equal and opposite reaction is Newton's third law of motion . This tells us that all forces in i n nature acts in pairs. These actions and reactions help in understanding the motion of bodies on which forces act. The law also helps in resolving issues in several applications of forces, namely when two bodies collide. The momentum of the bodies before collision and after collision can be worked out using the third law. If we consider bodies moving along a straight path, the momentum they possess is called linear momentum. If two spheres in a linear motion collide, their momentum before and after the collision can be related using Newton's third law of motion. The derivation from the third law of motion, using the mathematical expression of force, which is derived from Newton's second law of motion, enunciates that in the absence of external forces, if two bodies collide, the total momentum of the bodies before the collision and after the collision remains the same. This is the law of conservation of linear momentum. After collision if the two bodies stick together, their common speed or velocity can be calculated by using the law of conservation of linear momentum. There are several applications of Newton's third law of motion; the launching of satellites is one among them. Conservation of Momentum

There are very few laws in physics that are known to be valid in all situations. The "law of conservation of momentum" is one such very important law for which no exception has been

found so far. According to the law of conservation of momentum, when no external unbalanced force is acting, the sum of the momenta of a system of particles is constant. When this law is applied for a collision between two bodies, the total momentum of the colliding bodies before collision is equal to the total momentum after collision. Can we apply this law for a collision between two vehicles ? Yes, we can! This law is applicable for all types of collisions.


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We can apply this law for different situations. For example, consider a boy standing on a boat at rest. When he jumps from the boat on to the bank, the boat will no longer be at rest. The subsequent motion of the boat and its velocity can be explained using the law of conservation of momentum.

When a bullet is fired f ired from a gun, the gun gets some velocity in the opposite direction. The velocity of the gun, commonly called recoil velocity, can be calculated by applying the law of conservation of momentum.


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Gravitation Kepler's Law of Gravitation

The universe is one of the most fascinating subjects that were explored by many people around the world. Johannes Kepler, a student of Tyco Brahe, suggested three laws about the motion of the planets in the solar system, which revolutionised the comprehension about our solar system. These laws are named after him as Kepler's laws of planetary motion. The first law of Kepler enunciates that the shape of the orbits of the planets revolve around the Sun in an ellipse and not a circle as thought till then. This first law is referred to as the law of orbits. The

second law tells us about the area swept by the line joining a planet and the sun. According to Kepler's second law , the line joining the Sun and a planet covers equal areas in equal intervals

of time. This law is referred to as the law of equal areas.The speed of a planet in its orbit varies with its distance from the Sun. At perihelion, the position where the planet is closest to the Sun, the speed of the planet in its orbit is the maximum. On the other hand, at aphelion, the position where the planet is farthest from the Sun, the speed of the planet is the slowest. Kepler's third law tells us about the average radius of the orbit of a planet and its period of revolution. According to the third law, which is referred to as the law of periods, the square of

the period of revolution of the planet is proportional to the cube of the average radius of the planet's orbit.


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Universal Law of Gravitation

Every object in the universe attracts the other with a f orce. This is by virtue of the mass of the objects. This force of attraction was supposed to be thought upon by Newton while contemplating on the free fall of an apple towards the ground. The force of attraction, which is the gravitational pull due to mass of objects, exists e xists universally. The factors that affect gravitational force were studied and a law was put forth which is known as ' Newton's Universal Law of Gravitation '. The gravitational force between two objects in the universe is

directly proportional to the mass of the objects and is inversely proportional to the square of the distance between them. Hence, the mathematical form of the law is

where 'm1',

'm2' are the masses of the objects and 'r' ' r' is the distance between them. Equating both sides of the the expr expres essi sio on we get, et,

where here,, G is the the cons onstan tant of propo roporrtion tiona ality lity call calle ed the the

'universal gravitational constant '. The second part of the law is called the 'inverse square rule' or 'inverse square law '. The force with which earth attracts any object on its surface is the weight (W) of the object, which is the product of the mass (m) of the object and its acceleration due to gravity (g). 'W' changes from place to place on the earth on account of variation in 'g'. Thus the mass of an object remains the same throughout the universe where the weight of an object changes from place to place. What do we mean by the mass of a body? It is not easy to define certain fundamental quantities like "mass". One way of defining it is on the basis of the fact that the mass of an object is the measure of its inertia. Such a mass is known as " inertial mass". If a force "F" acting IX I.I.T. Foundation & Science Olympiad Physics Chapter Notes

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on a body produces an acceleration "a" in the body, then, its inertial mass is defined as the ratio of "F" and "a". The SI unit for mass is the "kilogram". When a body is placed in the earth's gravitational field, the body is attracted by the earth. The force with which the earth attracts a body is known as the "weight of the body".

If the acceleration gained by a body due to the earth's gravitational attraction is "g," then its weight is equal to "mg". Weight of a body = mg Since the "weight" of an object is a force, its SI unit i s the "newton". The weight of a body is a vector quantity, and always acts towards the centre of the earth. If a body is taken from the "earth" to the "moon", then there will be no change in its mass, but its weight will decrease. This is because the moon attracts the body with less force than that exerted by the earth. In fact, the weight of a body on the surface of the moon is only one-sixth of its weight on the surface of the earth.

Thrust and Pressure


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The suitcases or the handles of heavy luggage items have broad straps. Also the nails that are to be fixed into walls have pointed tips. Did you ever wonder if there is a scientific fact behind these mediocre observations? The force that acts on an object perpendicular to its surface is the thrust , measured in newton in the SI system or dyn in the CGS system of units. It is the thrust per unit surface, termed pressure that plays an important role in these situations. Even though the luggage is heavy and it weighs more, the force acting per unit area decreases with broad straps of the handles. Thus lesser pressure facilitates a person holding these items. Similarly, lesser surface area of the nails (hence the pointed tips) transfer a larger force exerted on them and facilitate easy fixing of them in walls. As pressure is force per unit area, its units are newton per metre square. One metre per metre square is termed pascal (Pa) after the name of the scientist Blaise Pascal. The pressure exerted by solids depends on their weight and surface area through which the weight acts. However, the pressure (P) exerted by liquids depends on their density (r), acceleration due to gravity (g) and the height (h) of the liquid column. Mathematically it is given by P = hrg. The pressure exerted at a point in a liquid is equal in magnitude in all directions, hence it is scalar. The increase in pressure of a liquid at a point is transmitted to all other parts of the liquid without any change. This is Pascal's law and it is widely used in various applications like hydraulic brakes of vehicles, vehicle lift platforms in garages etc.

Archimedes Principle and Buoyancy

Archimedes' principle. One of the most useful discoveries to mankind in the field of physics is Archimedes'

Based on this principle, a device called a hydrometer was developed which helps in measuring IX I.I.T. Foundation & Science Olympiad Physics Chapter Notes

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the density of liquids with ease. According to the principle, a solid that floats or is immersed i mmersed in a liquid appears to lose its weight which is equal to the weight of the liquid dis placed by the solid. Whether a given solid drowns or not in a given liquid depends on the density of the solid in comparison with that of the liquid. For an easy approach, we consider the relative density of the substance, which is the ratio of the density of the substance to the density of water, which obviously has no units but a mere number. If the relative density of the given solid is greater than that of the given liquid, it drowns in the liquid as there is i s a net downward force on the solid after it gets completely immersed in the liquid. If the relative density of the liquid and that of the solid are equal, then the solid just floats or drowns. This implies that the solid immerses in the given liquid and stays suspended at the kept position. If the rel ative density of the given solid is lesser than that of the given liquid, it floats in the liquid. This happens due to the upthrust or buoyant force of the liquid acting on the solid. The relative density of a floating solid in a given liquid gives the measure of the percentage of the solid that lies below the surface of the liquid. The "relative density" or "specific gravity" of a substance is defined as the ratio of its density to the density of water at four degrees Celsius.

This can be expressed in many ways. If the numerator and the denominator are both multiplied by "volume", then we get the expression relative density is equal to the ratio of "mass of the substance" to "mass of water of the same volume."

Again, when the numerator and the denominator are both multiplied by acceleration due to gravity "g", the expression becomes:


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When the substance is immersed in water, it displaces water of volume equal to its own volume. According to Archimedes' principle, the apparent loss of weight of a body immersed in water is equal to the weight of the water displaced. Therefore:

This expression can be used to find the relative density of a solid body. In order to find the relative density of a liquid, a solid body is taken and its weight is found in air. Then, the weight of the same body is f ound when it is completely immersed in the liquid whose relative density is to be found.Finally, the weight of the body i s found by immersing it completely in water. The relative density of the liquid can be found using the expression:


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Work and Energy Work

When a force displaces an object in its direction, di rection, work is said to be done. The force should be the net force and there should be a net displacement of the object. The work done is measured in joule in the SI system after the scientist James Prescott Joule. Erg is the CGS unit of work. If a force displaces the object in its direction, then the work done is positive, if the force and the displacement are in opposite directions, then the work is said to be negative. Usually negative work is attributed to the work done by friction. If the directions of force and the displacement are perpendicular to each other, the work done by the force on the object is zero.

Energy

The energy of an object is its ability to do work. Energy is the cause and work is its i ts effect. Therefore both work and energy have the same units, which is joule (J) in the SI system and erg in the CGS system. Energy is also a scalar quantity. Energy exists in many forms. To name some IX I.I.T. Foundation & Science Olympiad Physics Chapter Notes

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are mechanical energy which is either in the form f orm of potential energy or kinetic energy or a combination of the both, electrical energy, light energy, thermal energy etc. Potential energy is the energy possessed by a body by virtue of its position or state. It is further classified into gravitational potential energy (GPE) and elastic potential energy (EPE). GPE is by virtue of

height of a body from a reference level, given by the expression 'mgh' (m being mass of the body, g is acceleration due to gravity and h the height of the body from f rom the reference level) whereas EPE of a body is by virtue of its stretched state. Kinetic energy (KE) is the energy possessed by a body by virtue of its motion and is given by,

. The law of

conservation of energy, which is the fundamental law, says that energy can neither be created nor destroyed, the sum total energy existing in all forms in the universe remains constant. Energy can only be transformed from one form to another. Electrical energy commercially is measured in the units of kilowatt hour (kW h). Power is defined as the rate of doing work. Power is measured in watt which is equal to joule

per second. Power can also be measured as the product of force and velocity of an object. Energy can be expressed in terms of product of power and time. 6

1 kW h = 3.6 x 10 J


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Sound Production and Propagation of Sound

Like heat and light, sound is also a form of energy which has a characteristic of giving the sensation of hearing. Sound is produced by vibrating bodies. It propagates in air, in the form of longitudinal waves that comprise of compressions and rarefactions unlike the waves on a

water surface, which transverse in nature. The vibrations of a body cause the surrounding layers of air to vibrate to and fro, which cause these compressions and rarefactions. As sound requires a medium for propagation, it is a mechanical wave. The famous bell jar experiment proves this fact. Some of the properties of sound consist of its wavelength, frequency, amplitude and speed. Wavelength is the distance between two successive compressions or two successive rarefactions. Time period is the time taken by a particle to undergo one compression and the succeeding rarefaction. Frequency is the number of vibrations made by a particle i n one second, which is generally referred to as pitch. The loudness of sound depends on the amplitude of the vibrating particles. One can differentiate between two sounds by characteristics such as quality, pitch and loudness.


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Reflection of Sound

Like light, sound too undergoes reflection from any hard surface and obeys the same laws of reflection, which light obeys, that is angle of incidence is equal to the angle of reflection, the

reflected wave, the incident wave and the normal at the point of incidence lie in the same plane. The reflected sound is referred to as an echo. When we produce sound before a reflector, whether we hear the echo or not depends on the speed of the sound in the medium and the distance between the source/observer (which is the same in this case) and the reflector. To perceive two sounds they should have a time gap of at least 0.1 second. In a closed enclosure, one can hear multiple sounds (echoes) even after the source of sound stops producing the sound due to multiple reflections at different points on the surfaces of the enclosure. This phenomenon is called reverberation. Reflection of sound is used in various applications like stethoscope, echocardiography, sonar etc, although ultrasonics is used for things with a frequency greater than that of the audible range. The sounds whose frequency is less than 20 Hz are infrasonics, and greater than 20 kHz are ultrasonics. The human ear, that helps us hear sound, consists of three parts called the outer ear, middle ear and the inner ear. The outer ear consists of a pinna that helps in capturing the sound; the middle ear comprises of an eardrum and an auditory canal, hammer and anvil that amplify the incident sound; the inner ear consists of an auditory nerve that converts the amplified sound into electrical signals and sends it to the brain for perception. In case of hearing difficulties, one uses hearing aids that consist of a microphone and an amplifier.


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IX

I.I.T. Foundation & Science Olympiad Chemistry Chapter Notes

Chapter As Per NCERT Text Book 1. Matter in our Surroundings

Topic

States of Matter Inter Conversion of States of Matter Types of Substances

2. Is Matter Around Us Pure?

Types of Mixtures Methods of Separation of Mixtures

3. Atoms and Molecules

4. Structure of The Atom

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Atoms and Molecules Mole Concept Atomic Models Structure of an Atom


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1. Matter in our Surroundings States of Matter

Solids have definite shapes and volumes. Liquids do not have definite shapes.

Solids have definite shapes and volumes. Liquids do not have definite shapes. Liquids do have definite volumes. Gases do not have definite shapes or volumes.

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Solids have definite shape and volume.

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Cannot be compressed, except porous solids.

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Particles do not flow.

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Diffuse slowly.

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High force of attraction between particles.

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Very less inter-molecular space.

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Liquids take the shape of the container and have definite volume.

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Cannot be compressed

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Particles flow

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Diffuse fast

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Less force of attraction between particles.

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More inter-molecular space.

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Gases have no definite shape and volume.

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Can be compressed easily.

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Particles flow easily.

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Diffuse very fast.

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Very less force of attraction between particles.

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Large inter-molecular forces.


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Matter is any substance that has mass and occupies space Matter is made up of small particles. Properties of Particles

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Always in a state of random motion

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Possess kinetic energy

Inter Conversion of States of Matter

Melting is the process where solid changes into a liquid. Heat energy that is used up

by a body to change its state or phase is called latent heat. Latent Heat of Fusion: The amount of heat energy that is required to change unit mass of a solid into liquid at a

standard atmospheric pressure. Vaporisation The process where a liquid changes to gas. Latent Heat of Vaporisation

The amount of heat required to change a unit mass of liquid to gas at standard atmospheric pressure Evaporation The process where a liquid changes into vapour at

any temperature below its boiling point. Surface area , temperature and the wind are the factors that affect the rate of evaporation. The process where vapour changes to a liquid is called condensation. The process, where a liquid converts into a solid, is called freezing. The process, where a solid, on heating, directly changes into gas without changing into liquid, and a gas, on cooling, directly changes to solid without changing into liquid is called sublimation

Applying pressure and reducing temperature can liquefy gases. The phenomenon of the change of matter from one state to another and back to original state, by altering the temperature is called interconversion of states of matter.

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2. Is Matter Around Us Pure? Types of Substances

Changes are of two types - physical and chemical. Physical change:

A temporary change in which the composition of the substance remains the same and no new substance is formed but only a change of state occurs. Examples: Melting of ice, breaking of glass , tearing of paper, cutting of wood and changing of water to water vapour. Chemical change :

A permanent change in which a new substance is formed that has properties, which are different from the original substance ". For example: Formation of water, rusting of iron, burning of wood, lighting of fire crackers, burning of a match stick . Pure Substance : A substance which is made of one kind of particle .

Examples - iron, aluminium, silver and gold. Mixtures: Substance which contains two or more different kinds of particles .

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Homogeneous in nature.


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Cannot be broken down into simpler substances. An atom is the smallest unit and shows all the properties of an element Have a sharp melting point and boiling point. 

Classified into three classes as: o

metals

o

non-metals

o

metalloids

Metals are the elements which readily lose electrons to form positive ions or cations. Lustrous

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Good conductors of heat and electricity

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Malleable Ductile Sonorous

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Almost all metals are solids except mercury which is a liquid at room temperature.

The elements which readily gain electrons to form negative ions or anions. Non lustrous



Bad conductors of heat and electricity



Not malleable



Not ductile



Not sonorous



Exist in all the three states

A pure substance composed of atoms of two or more elements that are chemically bound with one another in fixed proportions

A molecule is the smallest particle of a compound with properties similar to that of a compound.

IX



Homogeneous in nature



Can be broken down into constituent elements


Page 5



Fixed composition



Distinct set of properties



Sharp melting and boiling points

A mixture in which various constituents are not mixed uniformly. Homogeneous Mixture



A mixture in which various constituents are mixed uniformly .



Properties of homogeneous mixture



Variable composition .



Constituents are seperable.



No new substance is formed.



Energy is neither given out nor absorbed.



Mixture does not have a sharp melting or boiling point.

Types of Mixtures



A solution is a homogeneous mixture of two or more substances.



The component of the solution that is present in a larger amount is called the solvent and that in smaller quantity is called the solute.

In tincture of iodine. The iodine is the solute and alcohol is the solvent. This is an example of a solid in a liquid solution . An aerated drink is a gas in liquid solution. Air is a homogeneous mixture of a number of gases. It is i s an example of a gas in gas mixture. Properties of a solution:

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

Homogeneous mixture of two or more substances.



Particles of a solution are smaller than 1 nm in diameter.



A beam of light directed through a solution is not visible. visi ble.



Solute particles cannot be separated by filtration.



Solute particles do not settle down when left l eft undisturbed.

The concentration of a solution can be expressed using two methods: 

Mass by mass percentage of a solution , Mass by volume percentage of a solution

Depending on the amount of solute present in the solution, solutions can be classified into saturated, unsaturated unsaturated or super saturated . Solubility can be defined as the maximum amount of solute by weight in grams

dissolved in 100 grams of solvent at constant temperature Properties of a Suspension 

Heterogeneous mixture



Particles are large



Unstable



Solute and solvent separated by filtration

Properties of a Colloid



A colloid is a heterogeneous mixture.



The particles of a colloid cannot be seen with the naked eye, and do d o not settle down when left undisturbed and cannot be separated by filtration.



Colloids can scatter a beam of light and make its path visible.



The dispersed particles in a colloid form the dispersed phase.

The component in which the dispersed phase is suspended is known as the dispersing medium Aerosol, foam, solid foam, emulsion, sol, solid sol , and gel are the different types of colloids.

The phenomenon of the scattering of light by colloidal particles is called the Tyndall effect.

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Methods of Separation of Mixtures

Mixtures on the basis of their physical states can be classified into



Solid - Solid Mixture



Solid - Liquid Mixture



Liquid - Liquid Mixture



Liquid - Gas Mixture



Gas - Gas Mixture.

The mixture of iron filings and sulphur powder can be separated by using magnets. Evaporation is the process of vaporizing the solvent to obtain the solute.

We can separate salt from a solution by evaporating the water from the solution. Filtration is a process by which insoluble solids can be removed from a liquid by using a filter paper.



In the filtration process:



liquid that filters through is the filtrate



undissolved solid particles are residue

You can separate the mixtures of solids and liquids such as fat in the cream by the process of centrifugation. Two immiscible liquids are separated by a separating funnel . Salt and a sublimable solid such as ammonium chloride, can be separated by the

process of sublimation. IX


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Solids like camphor , naphthalene and anthracene are examples of solids that sublimate. Chromatography is a method used to separate a mixture that comprises solutes that

dissolve in the same solvent. Chromatography is used for separating colours in a dye , pigments from natural colours and drugs from blood. Distillation: Conversion of a liquid into vapour by boiling and recondensing the vapour into liquid. A mixture of acetone and water can be separated by the process of distillation.

In case the difference in the boiling points of the liquids is less l ess than 25Kelvin temperature, we use the fractional distillation method. A mixture of n-hexane and nheptane can be separated through the process of fractional distillation.

The gases in the air are separated from one another by the fractional distillation of liquid air Crystallisation is used for:

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

Purification of salt that we get from sea water and



Separation of crystals of alum from impure samples


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3. Atoms and Molecules Atoms and Molecules

In any chemical reaction, the total mass of the substance before and after the reaction is the same although its matter undergoes a physical change.

In any chemical reaction, the total mass of the substance before and after the reaction is the same although its matter undergoes a physical change. law of definite proportions :

"In a chemical substance the elements are always present in definite proportions by mass". Law of Multiple Proportions

When two elements combine to form different compounds, then the weight of one is constant and the other has a simple ratio. Atom

The smallest particle of an element The first letter of the symbol is always in upper case. Some elements were represented by the starting alphabet of its name. For instance, 

Carbon as C



Boron as B



Oxygen as O



Sulphur as S



Nitrogen is written as N and



Hydrogen as H

Some elements have Latin names 

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Antimony is called stibium in Latin and the symbol is Sb.


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

Copper is known as cuprum and the symbol is Cu.



Gold as Aurium and represented by Au.



Iron as ferrum and the symbol is Fe.



Lead as plumbum and is represented as Pb.



Mercury as hydragyrum and is represented as Hg.



Kalium is the Latin name of potassium and its symbol is K.



Silver as argentum and it is represented as Ag. Natrium is the Latin name of sodium and it is represented as Na.



The Latin name of tin is stannum and the symbol is Sn.



Wolfram is the Latin name of tungsten and it is represented as W

The relative atomic masses of all elements have been found with wit h respect to an atom of carbon-12.

a molecule is the smallest particle of an element or compound that can exist independently

The number of atoms constituting a molecule is referred to as atomicity. Hydrogen, chlorine, nitrogen are diatomic .Elements like phosphorus and sulphur are

called poly atomic. Phosphorous is tetra atomic and sulphur is octa atomic. Elements combine to form compounds. The combining capacity of an element is known as valency A formula is the short hand representation of a compound. The formula of potassium hydroxide is KOH, magnesium nitrate is Mg (NO3)2, calcium phosphate is Ca3(PO4)2

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Mole Concept

One mole is defined as the amount of substance of a system which contains as many

entities like, atoms, molecules and ions as there are atoms in 12 grams of carbon 12". The number of atoms present in 12 grams of carbon 12 which is i s equal to 6.023X 10 23 . This is also known as Avogadro's constant. 

The atomic mass of an element is the mass of one atom of that element in atomic mass units (u). Molar mass of an atom is also known as gram atomic mass.



The sum of the atomic masses of all the atoms in a molecule of a substance is called the molecular mass.



The formula unit mass of a substance is the sum of the atomic masses of all atoms in a formula unit of a compound. It i s used for substances made up of ions.

3 moles of carbon dioxide are present in 132 grams of carbon dioxide . 4 moles are present in 24.088X10 23 particles of carbon dioxide 48 grams of magnesium contains 12.04 X 10 23 atom 3.6 grams of water 1.206 x 10 22 molecules

The number of atoms in 0.5 moles of carbon is 3.0115 X 10 23

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4. Structure Structu re of the Atom Atom Atomic Models

Matter is made of atoms and all atoms consist of charged particles.

According to Dalton's atomic theory an atom was indivisible and indestructible. Gold stein's work on the canal rays led to the discovery of protons. The mass of a proton was about 2000 times that of an electron and it carried a positive charge. J. J.Thomson in his experiments with cathode ray tube found that the particles were

attracted to the positive terminal of the tube . Thomson concluded that the particles must be negatively charged and called these ' electrons'. An electron has a negligible mass and has a charge of minus one. Thomson model was also called water melon model or Christmas pudding model.

Thomson's model. 

An atom is a positively charged sphere. Electrons are set within the sphere.



An atom is electrically neutral.

Rutherford's Experiment



Most alpha particles passed through the gold foil



Some particles were deflected slightly



A few particles appeared to rebound

Rutherford's Model



IX

Positively charged centre in an atom is called a nucleus.


Page 13



Electrons revolve around the nucleus in circular orbits .



A nucleus is much smaller than the atom.

Drawbacks Drawbacks of Rutherford's Model



Electrons move in their orbits

Atoms are unstable Bohr's Model



Electrons revolve in discrete orbits called shells.



Electrons do not radiate energy. Within an orbit, the energy of an electron is constant.

All the three scientists Thomson, Rutherford and Bohr received Nobel prizes for their theories.

Structure of an Atom

Atomic number (Z) is the number of protons in an atom; it is also equal to the number of electrons in the atom. Electrons are placed in fixed energy levels called shells. The arrangement of electrons in the shells is known as electronic configuration. configuration.

The maximum number of electrons that can be accommodated in any energy level of the atom is given by a formula 2n2, where n is the number of that energy level.

the outermost shell of an atom can have a maximum of eight electrons`

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The electrons are filled in K shell, then in L shell, M shell, N shell and so on. After a series of experiments and a detailed study by scientists like Louis de Broglie, Schrodinger, sommerfeld etc it was proved that shells have energy levels within them

and are sub-shells. These sub-shells are s, p, d and f. Electrons are distributed in these sub-shells. Every sub-shell can accommodate a fixed number of electrons. The s sub-shell can hold a maximum of two electrons, a maximum of six electrons in the p sub-shell, 10 electrons in d and 14 electrons in f. Electrons in an atom are arranged in definite shells. The electrons, which are present

in the outermost shell of an atom are referred as valence electrons Helium and neon, where helium has two electrons in its i ts outermost shell and all other inert gas elements have eight electrons

The combining capacity of the atoms to form molecules either with same or different elements is defined as valency. A neutral particle present in the nucleus. Chadwick discovered neutrons. atomic mass can be defined as

"The total number of protons and neutrons present in one atom of an element Mass number equals atomic number plus the number of neutrons Isotopes Atoms of the same element with the same atomic number but different mass numbers.

An isotope of uranium is used as fuel in a nuclear reactor. An isotope of cobalt is used in the treatment of cancer. For treating goitre, an isotope of iodine is used. Isobars Atoms of different elements with different atomic numbers but have the same mass number.

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IX I.I.T. Foundation & Science Olympiad Biology Chapter Notes Chapter As Per NCERT Text Book

Topics

Introduction to Cell 1. The Fundamental Unit of Life

Cell Structure Plant Tissues 2. Tissues

Animal Tissues Classification of Living Organisms 3. Diversity in Living Organisms

The Plant Kingdom The Animal Kingdom Diseases

4. Why Do We Fall Ill?

Transmission of Diseases Natural Resources 5. Natural Resources

Biogeochemical Cycles Improvement of Crop Resources 6. Improvement in Food Resources

Animal Husbandry

IX I.I.T. Foundation & Science Olympiad Biology Chapter Notes

Page 1

1. The Fundamental Unit of Life Introduction to Cell

All living organisms are made of cells. Marcello Malpighi, proposed that plants are made of tiny structural units called 'Utricles'. Robert Hooke observed many tiny, hollow, room- like structures in a thin slice of cork through a compound microscope and called them cells. Leeuwenhoek, in 1674, with the improved microscope, discovered free-living cells in pond

water for the first time. Robert Brown in 1831 discovered the nucleus in the cell. Purkinje in 1839 coined the term 'protoplasm'. Schleiden in 1838 and Schwann in 1839 proposed the cell theory that all plants and animals are composed of cells. Rudolf Virchow in 1855 further expanded the cell theory by saying omnis cellula-e-cellula, which means all cells arise from preexisting cells.Cell is derived from the Latin word "cellula" which means "a little room". Compound microscope consists of a stage where the specimen is placed under an objective

piece. The light reflected from the mirror passes onto the object. From the eye piece, a magnified image of the specimen is seen. The microscopic examination of a plant cell includes peeling off the thin layer using forceps. Spread the peel, put a drop of water and saffranin solution to it. Small chamber-like structures called cells can be observed. Unicellular organisms have single cells. While, multicellular organisms have multiple cells. All cells work as a team for the body through division of labour.

In Amoeba, a single cell is responsible for movement, intake of food, exchange of gases and excretion. Prokaryotes do not have a nuclear membrane and membrane bound organelles. Eukaryotes have a membrane bound nucleus and organelles. Structure of bacteria consists of

cell wall, plasma membrane and cytoplasm. Flagella are responsible for motility. The nucleoid IX I.I.T. Foundation & Science Olympiad Biology Chapter Notes

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is a circular DNA molecule that regulates all the functions of the cell. Difference between Prokaryotic and Eukaryotic organisms includes prokaryotic DNA is not bounded by a nuclear

membrane, while eukaryotic DNA is bounded by a nuclear membrane. The discovery of cells dates back to the 17th century, and is associated with the invention of the microscope.

In 1665, Robert Hooke, an English scientist, looked at a thin slice of cork, and observed tiny hollow structures that resembled a honeycomb. All living organisms are made of cells. Plant and animal cells are too small, and are visible only under a microscope. The microscopic examination of a plant cell shows a cell with a prominent vacuole, nucleus and cytoplasm. For the microscopic examination of animal cell, spread the specimen on a glass slide, and add a drop of water and methylene blue. Cells with darkly stained spherical nuclei at their centre can be observed. The shape of a cell is related to the specific function that it performs. Cells like the amoeba change their shape for motility. Cells like nerve cells have a fixed shape that suits their function of transmitting nerve impulses. Amoeba, chlamydomonas, paramecium and bacteria have single cells, which constitute the

whole organism. These are called unicellular organisms. Fungi, plants and animals have many cells that group together to form tissues. These organisms

are called multi-cellular organisms. Different organs perform different functions in multi-cellular organisms. For example, the human body has a heart to pump blood, a stomach to digest food, and kidneys to excrete waste.


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Eukaryotes can be unicellular, such as trypanosoma, euglena and paramecium, or multicellular, such as fungi, plants and animals.

The bacterial cell wall is a non-living layer composed of polysaccharides and proteins. The plasma membrane is a living membrane made of lipids. It is selectively permeable. Therefore,

it transports ions, nutrients and waste across the membrane. The cytoplasm is a clear, thick, jelly-like material that that forms the the seat for all cell functions. The cytoplasm of bacteria contains the nucleoid, ribosome and flagella. Ribosome transfers genetic messages into proteins.

There are differences between prokaryotic and eukaryotic organisms. A prokaryote has a single, circular DNA, while a eukaryote has DNA in paired chromosomes. Prokaryotes do not have vacuoles, while eukaryotes do.

Cell Structure

Cell wall is the outermost, non-living and rigid layer, seen in a plant cell. Plasma membrane is

selectively permeable. Diffusion is spontaneous movement of gases from a region of high concentration to a region of low concentration. Osmosis is diffusion of solvent molecules through a semi-permeable membrane from a region of low concentration to high concentration. If the medium surrounding the cell has a higher water concentration than the cell, called hypotonic solution, the cell gains water by osmosis and swells. If the medium has the same

water concentration as the cell called isotonic solution, there is no net movement of water IX I.I.T. Foundation & Science Olympiad Biology Chapter Notes

Page 4

through the membrane and the cell stays the same size. If the medium has a lower concentration of water than the cell called hypertonic solution, the cell loses water water by osmosis and then shrinks. Plasmolysis is the shrinking of the cell away from the cell wall. Nucleus is the control centre of the cell. Cytoplasm is the fluid living content between the plasma membrane and the nucleus. Protoplasm is the nucleus along with the cytoplasm that makes up the living content of the cell. Cytosol is the liquid part of the cytoplasm other than the organelles. Endoplasmic reticulum is

the protein synthesizing site of the cell. Ribosomes are small granules that synthesize proteins. Golgi apparatus is the site for storing and transporting proteins across the cytoplasm. Mitochondria is the power house of the cell. Lysosomes are known as suicide bags as these

enzymes destroy injured or old organelles and foreign substances like bacteria. Vacuoles are storage units in cells . Chromoplasts are colored plastids and leucoplasts are colorless plastids. Difference between Plant cell and animal cell includes size, vacuole, cell wall and

chloroplasts.


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2. Tissues Plant Tissues

A group of cells, that are similar in structure and work together to achieve a particular function, forms a tissue. Types of plant tissues include meristematic and permanent tissues. Meristematic tissues are rapidly dividing tissues. Apical meristem is present at the apical or growing tips of

stems and roots. Lateral meristem is present in the radial portion of the stem or root. Intercalary meristem occurs at the base of the leaves or at the internodes. Old meristematic

cells lose the capacity to divide and transform into permanent tissues.Types of permanent tissues

include

parenchyma,

collenchyma and

sclerenchyma.Parenchyma

containing

chloroplasts are called chlorenchyma. Parenchyma containing large air cavities are called aerenchyma.Complex permanent tissues are made of more than one type of cells and are of 2

types-xylem and phloem.Tracheids are tubular dead cells that transport water. Vessels are elongated dead cells that transport water and minerals. Xylem parenchyma cells are living and they store food. Xylem fibres are elongated dead cells with lignin that provide mechanical support. Sieve tubes are elongated living cells that transport food from leaves to the stem and the roots. Companion cells help in conduction of food to sieve tubes. Phloem parenchyma store food.Phloem fibre provide mechanical support. Protective tissue protects the plants from the surroundings. Epidermis is the outermost protective layer of roots, stems and leaves. Outermost layer in older roots and stems is called cork that contain dead cells. Epidermis is covered with a water proof layer called cuticle.


Page 6

Plants are stationary, and so some of the tissues they have are dead cells, which provide mechanical strength.

Plant growth occurs only at the tips of the stem and the root, due to the presence of meristematic tissues in these regions. Meristematic cells are living, cubical cells with a large nucleus. These cells are closely packed

with no intercellular spaces. Depending on the region where the meristematic tissues are present, they are classified as apical, lateral and intercalary meristems. Apical meristem increases the length of the plant, lateral meristem increases the girth of the

plant, while intercalary meristem increases the length of the internode. Old meristematic cells transform into permanent tissues. This process of taking up a permanent shape, size, and function is called differentiation. Parenchyma are living, polygonal cells with a large central vacuole, and have intercellular spaces between them. Parenchymatous cells form the ground tissue and pith, the chlorenchyma that help in

photosynthesis, the aerenchyma that help in buoyancy, and the parenchymatous cells in fruits and vegetables that help in the storage of starch. Collenchyma are elongated living cells with small intercellular spaces. Their cell walls are

made of cellulose and pectin. Collenchyma occur in theperipheral regions of stems and leaves, and provide mechanical support and flexibility in plants. Sclerenchyma are long, dead cells with a deposit of lignin in their cell wall. They have no intercellular spaces.


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Sclerenchyma occur around the vascular tissues in stems, in the veins of leaves, and in the covering of seeds and nuts. They provide strength to the plant.

The different components of the xylem include tracheids, vessels, xylem parenchyma and xylem fibres. Tracheids and xylem fibres are made of lignin, which provides mechanical support to the

plant. The different elements of Phloem include sieve tubes, companion cells, phloem parenchyma and phloem fibres. Protective tissues include the epidermis and cork.

The epidermis is perforated by the stomata at certain places. The stomata help in gaseous exchange and loss of water. As the plant grows older, the outer protective tissue replaces the epidermal cells in older roots and stems, called cork. Cork cells are dead and lack intercellular spaces. Their cell walls are thickened by suberin,

which makes them impermeable.

Animal Tissues

Types of Animal Tissues include epithelial tissue, connective tissue, muscular tissue and nervous tissue.Epithelial tissues form a protective layer. Different types of epithelial tissues IX I.I.T. Foundation & Science Olympiad Biology Chapter Notes

Page 8

are classified based on their shape and function. Squamous epithelium are found in the organs to provide mechanical support. Columnar epithelium are found in the lining of the organs to facilitate the movement of nutrients. Glandular epithelium are found in the glands to produce secretions. Ciliated epithelium are found in the lining of the respiratory tract. Cuboidal epithelium are found in organs to provide mechanical support. Stratified epithelium are found

in places of wear and tear. Connective tissue connects different organs. Different types of connective tissues are classified based on their shape and functions. Blood is a type of fluid connective tissue. Bone is a hard porous tissue that protects the internal organs. Fibrous connective tissue pack

and bind various organs. Ligaments connect two bones and tendons connect bones to the muscles. Cartilage is found at the end of long bones to give flexibility. Areolar connective tissue fills the space inside organs. Adipose tissue is found below the skin and around kidneys.

Man can move because of the elasticity and flexibility of muscular tissues. Striated muscles help us move our limbs at will. Unstriated muscles are found in the iris of the eye and bronchi of the lungs. The contraction and relaxation of cardiac muscles cause heart beats. Nervous tissue transfer information from one part of the body to another. Nervous tissues have elongated

cells called neurons. Neurons join end to end to form nerve fibres. A group of cells forms a tissue. Different tissues form an organ, and many organs form an organism. Epithelial tissues act like a barrier to keep the different body systems separate. Squamous epithelium has flat and thin cells with no intercellular spaces. Squamous epithelium provides mechanical support and is found in the outer layer of the skin,

lining the cavities of ducts, blood vessels and the chambers of the heart. Columnar epithelium consists of cylindrical cells. It is found in the lining of the stomach and intestines, and facilitates the movement of nutrients across the epithelial barrier. Glandular epithelium consists of modified columnar cells, and is found in the sweat glands

and tear glands to produce secretions. IX I.I.T. Foundation & Science Olympiad Biology Chapter Notes

Page 9

Ciliated epithelium consists of columnar cells with cilia. These cilia push the mucus forward

into the nasal tract to clear it. Cuboidal epithelium consists of cubical cells. It is found in the lining of the kidney tubules, salivary glands and thyroid glands, where it provides mechanical support. Stratified epithelium has epithelial cells lined up one over another. It is found in the epidermis

of the skin, the lining of the mouth cavity, and oesophagus. Blood has plasma and blood cells. The blood cells suspended in the plasma include RBC's, WBC's and platelets. Blood flows within blood vessels, and transports gases, digested food and hormones to

different parts of the body. Bone cells are embedded in a hard matrix composed of calcium and phosphorus compounds.

Bones anchor the muscles. Ligaments are tough and elastic, and provide strength and flexibility. Tendons are tough and

non-elastic, and provide great strength and limited flexibility. Cartilage has widely spaced cells suspended in a matrix of proteins and sugars. It is found in

the nose, ears, and the rings of the trachea to give flexibility. Areolar connective tissue has irregular shaped cells, and is found between the skin and muscles, and around blood vessels and nerves. Adipose tissue contains cells filled with fat globules. It is found below the skin and acts as an insulator.

Muscular tissues have elongated cells, called muscle fibres. Muscular tissues are of three kinds: striated muscles, unstriated muscles and cardiac muscles.


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Striated muscles are cylindrical, unbranched and multinucleated. Each muscle fibre has dark bands alternating with light bands, called striations. Striated muscles are called voluntary muscles, and are found in our limbs, body wall, face and neck. Unstriated muscles are spindle shaped with one nucleus. They do not have striations, and are

called smooth or involuntary muscles. The contraction and relaxation of these muscles helps to push food down to the alimentary canal. Cardiac muscles are also called involuntary muscles. They are branched, cylindrical fibres

with a single nucleus. Each neuron consists of a cell body, which contains a nucleus, cytoplasm, called cyton, and elongated hair-like extensions, called dendrites. One of the dendrites, called the axon, is very long. Nervous tissues are found in the brain, spinal cord and nerves.


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3. Why Do We Fall Ill? Diseases

Health is defined as a state of physical, mental and social well being. A disease is an unhealthy

condition caused by microorganisms, improper diet or it may be inherited. Classification of diseases is based on prevalence, occurrence or spread and duration. Epidemics are outbreak

diseases that attack many people at the same time and spread very quickly. Classification of diseases based on occurrence or spread includes Infectious and Non-Infectious Diseases. Infectious diseases spread from one person to another through air, water, food, physical contact

and insects, hence also called communicable diseases. Non-Infectious Diseases such as blood pressure are caused by nutritional deficiencies, hence called non-communicable diseases. Classification of diseases based on duration includes acute and chronic diseases. Diseases that

last for a short period are called acute diseases. Diseases that last for a lifetime are called chronic diseases. Causes of diseases might be due to contaminated water, lack of good nourishment and genetic

abnormalities. Bacteria, viruses, fungi, protozoa and worms that cause diseases are called infectious agents. Diseases caused by bacteria are typhoid, cholera, tuberculosis and anthrax. Diseases caused by viruses are common cold, influenza, dengue fever and AIDS. Diseases caused by fungi are commonly skin infections. Diseases caused by protozoa are Kala-Azar and

Sleeping Sickness. Diseases caused by worms are intestinal infections and lymphatic infections like elephantiasis. Organ and Tissue specific Manifestations of microbes depends on the mode


Page 12

of entry of microbes. Acquired Immuno Deficiency Syndrome or AIDS is so called because the AIDS virus breaks down the body's immune cells and organs that comprise the immune system. Health is often affected by diseases. "Disease" literally means being uncomfortable.

When you get a disease, the organ systems stop functioning properly, which gives rise to symptoms such as headache, cough, loose motion and wounds with pus.

The plague is an example of an epidemic disease. Infectious diseases are caused by micro-organisms like bacteria, virus, fungi and protozoa.

Diseases like cancer caused by genetic abnormalities are non-infectious diseases. They are called non-communicable diseases as they do not spread from one person to another. The common cold that lasts for a few days is an example of acute disease. Elephantiasis and diabetes that last for a lifetime are examples of chronic diseases. Signs and symptoms give a definite indication of the presence of a particular disease.

The causes of repeated v omiting of a baby might be due to several reasons. Bacteria could have entered the baby's system through unclean drinking water, which might be a first-level cause of the disease. The baby might not be well nourished, which might be a second-level cause of the disease. The baby might also be genetically more likely to suffer from vomiting when exposed to such bacteria, which might be a third level-cause of the disease. Staphylococci bacteria cause acne, or pimples, on the skin.

Protozoan organisms like Leishmania cause the Kala-Azar disease, manifested by fever and enlargement of the liver.


Page 13

Trypanosoma cause sleeping sickness, manifested by confusion, sleeping during the day and staying awake during the night. Infectious agents attack a specific part of the body.

If microbes enter from the air via the nose, they localise in the lungs and cause tuberculosis. If microbes enter through food or water via the mouth, they stay in the gut lining and cause typhoid.

If microbes enter the liver, like viruses do, they cause jaundice. Microbes that cause malaria enter through a mosquito bite, go into the liver, and later destroy the red blood cells. Symptoms tell us about the target organ infected.

If the symptoms are cough and breathlessness, the then lungs are the target. Jaundice is a symptom of the liver, which is also a target organ.

If the symptoms are headache, vomiting, fits or unconsciousness, then the brain is the target. AIDS is caused by a virus named Human Immuno Deficiency Virus or HIV.

An AIDS patient's body can no longer fight minor infections like the common cold, which leads to major infections like pneumonia, diarrhoea with blood loss, etc.


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Transmission of Diseases

Common ways of transmission of diseases includes direct contact, air, water, food and other

animals. Overcrowded and poorly ventilated housing is a main factor in the spread of airborne diseases. Cholera is a water borne disease. Syphilis and AIDS are diseases caused by physical contact. Organisms that carry microbes from a sick person to a healthy person are called vectors. Rabies and malaria are diseases caused by animals. Common effects of a infectious disease is activation of immune system and inflammation. Immune system recruits many cells to

the affected tissue to kill the infectious agents, a process called inflammation. Treatment of infectious diseases involves either reducing the effects of the disease or eliminate the cause of

the disease. Antibiotics are more effective against bacterial infections. Anti-viral drugs are meant for treating viral diseases. Problems faced in treatment of diseases involves damage of body functions or may never

recover completely. Prevention of infectious diseases is better than cure. There is an important role of immune system in prevention of infectious diseases. Person infected with chicken pox

won't get the disease again, because of our body cells that react against microbes and remember by producing memory cells. Immunization is the protection of individuals from communicable diseases by administration of a suspension of killed micro-organisms. A hundred years ago, smallpox epidemics were common throughout the world. Virus like smallpox was eliminated

from the world through vaccines, a process called vaccinations. First vaccine was developed against small pox by Edward Jenner, hence called " Father of Immunology". Diseases spread through microbial organisms from an infected person to a healthy person. IX I.I.T. Foundation & Science Olympiad Biology Chapter Notes

Page 15

In closed areas, the droplet nuclei re-circulate and pose a risk in the spread of airborne diseases, like the common cold, pneumonia and tuberculosis.

When the excreta of animals and humans, suffering from infectious diseases, get mixed with drinking water, water becomes contaminated. Other than sexual contact, AIDS is also transmitted from an infected mother to her child, during pregnancy or through breastfeeding. It can also spread by transferring the blood of an infected

person to a healthy person. The most common vectors that transfer micro-organisms from one human being to another are female mosquitoes, dogs, hens, etc.

Animals like dogs and cats transfer the rabies virus when they bite human beings. The group of cells and organs that protect the body from foreign invaders is called the immune system.

An active immune system recruits many cells to the affected tissue to kill the infectious agents. This process is called inflammation, which leads to a swelling and pain in that area, and can even cause a fever. The antibiotic penicillin blocks the cell-wall synthesis of bacteria, thereby killing the bacteria inside the body. Anti-viral drugs are difficult to prepare as compared to anti-bacterial drugs, because viruses

are unique in the sense that they grow only inside the host and keep on changing their form during the different stages of their life. An infected person may serve as the source from which the infection may spread to other people. Providing living conditions that are not over-crowded, providing clean drinking water, and keeping our surroundings clean can prevent infectious diseases.


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When the chicken pox virus enters the body for the second time, the memory cells fight with the microbes more efficiently, thereby eliminating the infection faster than the first time. The smallpox virus can be prevented from infecting for the first time through vaccination. In this process, foreign dead smallpox virus is injected into the body as a suspension. This is called a vaccine. There are vaccines that provide a means of prevention against polio, whooping cough, tetanus, etc.


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4. Natural Resources Natural Resources

The important natural resources available on Earth are land, water and air. The region of Earth where the atmosphere, hydrosphere and lithosphere interact and support life is called biosphere. Living organisms constitute the biotic component of the biosphere. Air, water and

soil constitute the abiotic component of the biosphere. Air is a mixture of gases like nitrogen, oxygen and carbon dioxide. Plants and animals use oxygen for respiration, carbon dioxide is

used by plants for photosynthesis are the uses of air. Experiment -role of air in climate control: concludes that soil gets colder faster than water and air. Why is the land near water bodies cool? - During the day, heated air above the land causes air to move from the sea to the

land and making the land near water bodies colder. At night, air moves from land to the sea, creating a land breeze. When the temperature is low, precipitation may occur in the form of snow, sleet or hail. In India, rain is brought by monsoons and are of two types namely south-west and north-east. Contamination of air is

called air pollution. Fresh water is found on snow-covered mountains, in rivers and lakes. Saline water is found in seas and oceans. Contamination of water is called water pollution.

Industry chemicals, urban sewage and pesticides are the causes of water pollution. Soil contains soil particles, humus and living organisms. Sun, water, wind and living organisms help in formation of soil. The addition of substances that adversely affect soil fertility is called soil pollution.


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The solid outermost layer of the earth's crust and the rigid upper part of its mantle is called the lithosphere.

The water that is found on the earth's surface, above it as clouds and below it as groundwater, is called the hydrosphere. The air, which includes gases that cover the earth like a blanket, is called the atmosphere. Nitrogen is used to produce a number of organic molecules, like proteins. Nitrogen is fixed in

plants and is transferred to animals through the food chain. Plants and animals use oxygen for respiration. The combustion of fossil fuels also requires oxygen. Marine animals absorb atmospheric carbon dioxide and form carbonic acid. These carbonate ions are used by marine animals to make shells. Experiment- the role of air in climate control: Take three beakers. Fill the first with water, the

second with soil, and leave the third empty. Place the beakers in sunlight for three hours and take the thermometer readings. The temperature reads more in the second beaker than in the others. This indicates that soil gets hot faster than water and air. Experiment - the role of air in climate control: If you perform the same experiment under the

shade, the temperature reads more in the first beaker than in the others. This indicates that soil gets cooled faster than water and air.

During the day, air moves from the high pressure area over the sea to the low pressure area over land, creating a sea breeze. At night, since soil cools faster than water, the air above the land is cooler than the air above the sea. This causes air to move from the high pressure area over land to the low pressure area over the sea, creating a land breeze.


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Water bodies get heated during the day and evaporate into the air. As the vapour rises, it cools. This causes the vapour to condense into tiny water droplets, which fall down as rain. The south-west monsoon brings the maximum amount of rainfall over India. Burning fossil fuels contributes to the addition of suspended un-burnt hydrocarbon particles to the air. Fuels like coal and petroleum release nitrogen and sulphur oxides. These oxides of nitrogen and sulphur dissolve in the air and form acid rain. Dissolved oxygen is needed by aquatic animals. A rise in the temperature of water removes the

dissolved oxygen and causes the death of many aquatic animals. How is Formation of soil formed? Due to uneven contraction and expansion, rocks crack and

break into smaller particles of soil. The water logged in the cracks of rocks freezes, and the cracks widen to eventually break the rocks into soil. Living organisms like lichens grow on the surface of rocks and release chemicals that powder the rocks to soil. Flowing water in rivers breaks hard rocks and forms soil particles. Strong winds erode rocks and carry sand from one place to another. Consequences of soil pollution: Use of fertilisers and pesticides destroy soil structure by

killing micro-organisms and earthworms. Deforestation leads to soil erosion. Fine particles of soil are also carried away by water and wind.


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Bio-Geo Chemical Cycle

Cycling of chemicals between biological and geological world is called biogeochemical cycle. Four biogeochemical cycles includes water cycle, nitrogen cycle, carbon cycle and oxygen cycle. Water enters the atmosphere as water vapour by evaporation. Water from plants

evaporates as vapour into the atmosphere through transpiration. Water vapour in the atmosphere form clouds, called condensation. Clouds break into rain, snow or fog, called precipitation. Photosynthesis with respect to carbon cycle: Plant use sunlight, carbon dioxide

in the atmosphere to form carbohydrates. Respiration with respect to carbon cycle: Plants and animals breakdown carbohydrates for energy and release of carbon dioxide. Decomposition with respect to carbon cycle: Bacteria and fungi decay dead plants and animals releasing

carbon dioxide. Combustion with respect to carbon cycle: Burning of fossil feuls release carbon dioxide into the atmosphere. Types of nitrogen fixation include both biological nitrogen fixation and physical nitrogen fixation. Bacteria in the soil decompose the organic

matter into ammonia , called ammonification. Bacteria in the soil convert ammonia to nitrate, called nitrification. Denitrifying bacteria convert nitrite and nitrate to nitrogen, called denitrification. Respiration and Combustion with Respect to Oxygen Cycle:

Plants and animals use atmospheric oxygen during respiration and oxygen is used for burning of fossil fuels. Temperature inside a glass house is much higher than the surroundings, such enclosures are called greenhouse. Carbon dioxide trap the heat and thereby increase the temperature on earth, called the greenhouse effect. Ozone absorbs harmful ultraviolet radiations from the Sun. ozone layer is depleting due to an increase in chlorofluorocarbons. IX I.I.T. Foundation & Science Olympiad Biology Chapter Notes

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The biotic and abiotic components of the

biosphere constantly

interact

through

biogeochemical cycles.

During these interactions, there is a transfer of nutrients between living organisms, or bio, and the non-living environment, or geo. Water evaporates from the water bodies, and returns as rain and snow, which, in turn, flows back into the seas via rivers. This cyclic movement of water from the land to the ocean to the atmosphere and back to the land is called the water cycle. Water from plants evaporates as vapour into the atmosphere through the stoma in the leaves and stems. Water is maintained in the biosphere by rainwater flowing back into the water bodies. Some of

it penetrates the earth's surface and is logged as groundwater. Carbon Cycle - Decomposition: Dead plant and animal remains in the soil are converted into coal, petroleum and natural gas, better known as fossil fuels. These fuels are used for cooking,

transportation and industrial processes. Nitrogen makes up 78 per cent of the earth's atmosphere. Nitrogen is an essential constituent of proteins, nucleic acids like DNA and RNA, vitamins, and chlorophyll. Legumes have nitrogen-fixing bacteria in their root nodules. These bacteria convert atmospheric nitrogen into ammonia, which is utilised readily by plants. Nitrogen-fixing bacteria along with free living bacteria in the soil achieve 90 per cent of nitrogen fixation.

When lightning occurs, the high temperature and pressure makes nitrogen and water combine to form nitrates and nitrites. These compounds dissolve in water and are readily used by plants. The sequence in which nitrogen passes from the atmosphere to the soil and organisms, and then is eventually released back into the atmosphere, is called the nitrogen cycle.


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Oxygen makes up 21 per cent of the air, and is an essential constituent of carbohydrates, proteins, fats and nucleic acids. Oxygen is found in air, in combined form as carbon dioxide, and in the earth's crust as carbonates, sulphates and nitrates.

The sequence in which oxygen from the atmosphere is used by organisms and eventually released back into the atmosphere through photosynthesis is called the oxygen cycle. The ozone layer prevents harmful radiations from reaching the earth's surface, where they might damage life forms.


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5. Improvement in Food Resources Improvement in Crop Resources

The green revolution contributed to increased food-grain production, and the white revolution

contributed to increased availability of milk. Sources of Nutrition include cereals, pulses, oil seeds, vegetables, spices and fruits. Kharif crops are grown in the rainy season, which is from June to October. Rabi crops are grown in the winter season from November to April. Desirable traits are incorporated into the plant by hybridisation. Genetic modification in plants produced plants that are able to survive in a drought and water logged conditions. Macronutrients includes nitrogen, phosphorous, potassium, calcium, magnesium, and sulphur. Micronutrients includes iron, manganese, boron, zinc, copper, molybdenum and chlorine. Manure increases soil fertility. Types of manure includes compost, vermi-compost and green manure. Fertilizers supply nitrogen, phosphorus and potassium to the plants. Blue green algae are used as biofertilizers and neem leaves or turmeric are used as biopesticides. Irrigation is the artificial supply of water to the soil by means such as wells, canals, rivers and tanks. Types of wells include dug well and tube well. When canal flow is

insufficient due to inadequate reservoir release, river lift systems are used. Rainwater harvesting increases the ground water levels and reduce soil erosion. Cropping patterns -

Types: mixed cropping, inter cropping and crop rotation. Nurturing crop plants against the damages caused by weeds, pests and diseases is crop protection management. Diseases in plants are caused by pests, bacteria, fungi and viruses and can be controlled by spraying pesticides, insecticides and fungicides. Exposure to chemical fumes kills pests, called fumigation. IX I.I.T. Foundation & Science Olympiad Biology Chapter Notes

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Cereals provide carbohydrates, pulses provide proteins, oil seeds provide fats, and vegetables, spices and fruits provide vitamins and minerals.

Kharif crops include paddy, soyabean, maize, cotton, green gram and black gram. Wheat, gram, peas and linseed are rabi crops. In India, the production of food grains increased 4 times from 1960 to 2000. This increase in food production was due to crop variety improvement, crop production improvement and crop protection management. Crop variety improvement can be achieved by the process of selection. The criteria for selection are high yield, disease resistance, response to fertilisers, tolerance to climate, etc. Hybridisation occurs by a cross between two different varieties, which is known as intervarietal crossing, or between two different genera, known as inter-generic crossing, or

between two different species, known as inter-specific crossing. Crop yield can also be increased by introducing desirable genes into the crop plant. This results in genetically modified crop plants that are able to survive in a drought or flood. Crop production improvement is the protection of crops that are growing or have been

harvested. Nutrient management, irrigation and cropping patterns can help improve crop production. Air supplies carbon and oxygen. Water supplies hydrogen and oxygen. Soil supplies the

remaining 13 nutrients to plants. Among these 13 nutrients, 6 nutrients are used in large quantities by plants, and are called macro-nutrients. The other 7 nutrients are used by plants in smaller quantities, and are called micro-nutrients. A deficiency of these nutrients makes plants prone to diseases. Manure is produced naturally by the decomposition of animal excreta and plant waste. It

contains organic matter, and thus, improves the water-holding capacity in sandy soils, and prevents water logging in clayey soils.


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Compost is prepared by decomposing farm waste like livestock excreta, vegetable waste,

domestic and sewage waste in pits. This process is called composting. Compost is also prepared by using earthworms to hasten the decomposition of plant and animal

waste. This process is called vermi-composting. Before sowing seeds, plants like the sunhemp are grown and ploughed into the soil. These green plants enrich the soil with nitrogen and phosphorous. This is called green manure. The continuous use of chemical fertilisers kills useful micro-organisms and even destroys soil fertility. So chemical fertilisers are being replaced by bio-fertilisers. In a well, water is collected from the water-bearing strata. Tube wells can tap water from the deeper strata. Water is lifted from tube wells by pumps. Canals receive water from reservoirs or rivers. The main canal is divided into branched canals to irrigate the fields. Tanks are small reservoirs, which store run-off water. Mixed cropping is growing two or more crops simultaneously on the same piece of land, which

includes wheat and gram, or groundnut and sunflower. Inter-cropping is growing two or more crops simultaneously on the same field with some rows

of one crop alternating with some rows of another, like soyabean and maize, or finger millet and cowpea. This ensures maximum utilisation of the nutrients, and also prevents pests and diseases of one crop spreading to the other crop in a field. The difference between mixed cropping and inter-cropping is that in mixed cropping, some rows of one crop alternate with some rows of another, while in inter-cropping, the two crops are sown in alternate rows. Growing two or three different crops in a year on a piece of land is known as crop rotation. Examples include cereals alternating with legumes, soyabean alternating with maize.


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Nurturing crop plants against damage by weeds, pests and disease is known as crop protection management. Weeds can be removed by spraying herbicides or by removing them mechanically. Weeds like Xanthium, Parthenium and Cyperinus rotundus are unwanted plants in a crop

field. They compete with the crop plants for food, space and light, and finally reduce crop growth. Diseases in plants are caused by pathogens such as bacteria and fungi, and viruses, just like in

humans. These pathogens are transmitted through soil, water and air. Storage losses in crops are due to biotic factors like insects, rodents, fungi, mites and bacteria. Abiotic factors like inappropriate levels of moisture and temperature in the storage area also

damage crops.

Animal Husbandry

Animal husbandry is the farming and management of animal livestock including cattle, goat,

sheep, poultry, and fish. The practice of rearing cattle is cattle farming. Milk-producing female animals are dairy animals. Male cattle used for farm labour are draught animals. Roughage feed contain high fibre content and concentrate feed contain low fibre and high protein content .

Diseases in cattle are caused by external parasites and internal parasites. The period following the birth of a calf is lactation period. Cross breeding in cows lead to a new breed with a long lactation period as well as a strong resistance to diseases. Poultry farming is the practice of raising poultry. Cross-breeding in poultry lead to new varieties with desirable traits. Enclosures IX I.I.T. Foundation & Science Olympiad Biology Chapter Notes

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like tanks are used to produce fish for commercial purposes, called

fish farming or

aquaculture. Capture fishing involves obtaining fish from natural resources and culture fishing involves

culturing the fish in small enclosures. Fishing in saltwater regions is called Marine Fisheries. Mariculture involves culturing of fish in marine water. Inland fisheries comprise canals and

reservoirs where fish are trapped or captured. Another rich source of fish are found in reservoirs where fresh water and sea water mix , these regions are called estuaries. Composite Fish Farming is intensive fish farming of five or six fish species, with different food habits in a single

fishpond. Practice of maintaining honey bee colonies in beehives is called bee-keeping or apiculture. Beehives are enclosed structures in which honey bees live and raise their young. Varieties of honey-bees are Apis cerana indica, Apis dorsata and Apis florae. Animal husbandry includes feeding, breeding, and disease control of livestock animals. Cattle farming is carried out for milk production and agricultural work.

The two major species of Indian cattle are Bos indicus, or cows, and Bos bubalis, or buffaloes. Animal feed is of two types: roughage feed, which is used for energy, and concentrate feed,

which is used for increasing body weight. During the lactation period, high milk production is observed. By lengthening the lactation period through hormonal stimulation, milk production can be enhanced. Foreign breeds like the Jersey cow, which has a long lactation period, and local breeds like the Red Sindhi cow, with high resistance to disease, when cross-bred, produce cattle with the

desired qualities. Poultry farming is carried out for producing eggs and meat. Fowls are used for producing eggs, and broilers are used for producing meat.


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The Indian breed Aseel is cross-bred with the foreign breed Leghorn to develop new varieties with the desirable traits. The desirable traits include dwarf broiler parents so that they can be used as meat within a short period of time, higher number and better quality of chicks, and tolerance to high temperatures during summer. Generally, fish production involves two main species of fish - finned true fish such as catla and Rohu, and shellfish such as prawns and molluscs. Marine fish of high economic value are farmed in seawater, like Bhetki and pearl spots. Shellfish, such as prawns, mussels and oysters, are also farmed in seawater. Oysters are

cultivated for the pearls that they make. Fish are captured by locating large schools of fish in the open sea using satellites and echosounders. Composite fish farming includes Catla, the surface feeders, Rohu, which feed in the middle

zone of a pond, Mrigal and common carp, which are bottom feeders, and grass carp, which feed on weeds. These species can co-exist in a single pond, and thus, increase the yield of fish from the pond. Fish are injected with hormones that stimulate the production of eggs or seed. This ensures the supply of pure fish seed of in the desired quantities. The practice of maintaining honey bee colonies in beehives is called bee-keeping or apiculture. For commercial honey production, bee farms or apiaries are established. Beehives are a source of honey used in food and medicines, and wax used in ointments.

An Italian bee variety, Apis mellifera , is commonly used for commercial honey production, as the bees of this species have a high capacity to collect honey.


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Class-IX-I.I.T.Foundation

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