2012

Jai Kumar Gupta

Brilliant Public School, Sitamarhi

19/04/2012

VI I.I.T. Foundation, N.T.S.E.& Science Olympiad Curriculum &

Chapter Notes

VI I.I.T. Foundation, N.T.S.E.& Science Olympiad Curriculum Page 1

Physics -VI

Chapters as per NCERT Text Book Topics

1. Motion and Measurement of Distances

Transportation and Distances

Measuring Length and its Accuracy

Rest and Motion

2. Light, Shadows and Reflections

Types of Media

Shadows and Pin Hole Camera

Mirrors and Reflection

3. Electricity and Circuits

Electric Cell and Torch Bulb

Electric Circuit

Electric Conductors and Insulators

4. Fun with Magnets

Magnetic and Non-magnetic Materials

Properties of a Magnet

Chemistry- VI

1. Fibre to Fabric Fibres

2. Sorting Materials into groups Properties of Materials

3. Separation of Substances

Methods of Separation I

Methods of Separation II

4. Changes Around us Changes around us

Biology- VI

1. Food: Where does it Come from? Sources of Food

2. Components of Food

Test For Starch, Proteins and Fats

Nutrients and Balanced Diet

Deficiency Diseases

3. Getting to Know Plants

Categories of Plants

Parts of a Plant

Parts of a Flower

4. Body Movements

Joints and their Types

Bones and Skeleton

Gait of Animals

5. The Living Organisms and their

Surroundings

Habitat and Adaptation

Types of Habitat

Characteristics of Living Things

6. Water

Water Cycle

Effects of Rainfall - Draughts and Floods

7. Air Around Us All about Air

8. Garbage In, Garbage Out

Garbage Disposal and Vermicompost

Recycling Paper and Plastics

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 1

VI I.I.T.Foundation, N.T.S.E.& Science Olympiad Physics Chapter Notes

Physics Chapters as per NCERT Text Book Topics

1. Motion and Measurement of Distances Transportation and Distances

Measuring Length and its Accuracy

Rest and Motion

2. Light, Shadows and Reflections Types of Media

Shadows and Pin Hole Camera

Mirrors and Reflection

3. Electricity and Circuits Electric Cell and Torch Bulb

Electric Circuit

Electric Conductors and Insulators

4. Fun with Magnets Magnetic and Non-magnetic Materials

Properties of a Magnet

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 2

1. Transportation and Distances

Before the invention of the wheel, the only

means of transportation was walking.

Evolution of Transport

Before the invention of the wheel, the only means of transportation was walking. For

transporting goods, people used animals like donkeys, horses, mules, elephants, oxen, sled

dogs, and even bison. Boats were also used as a means of transportation on water. The earliest

boats were simple logs of wood with a hollow cavity.

The oldest wheel was discovered in Mesopotamia, and is believed to be over 5,500 years old.

Fixed wheels for carts were invented around 3500 BC, according to some historians. After the

invention of the wheel, man started using animals to pull vehicles that moved on wheels, and

thus, bullock carts and chariots came into existence. Till the 19th century, most forms of

transport used only animals

The bicycle was invented in the late 18th century bicycles. The first bicycles did not have brakes,

though. It was up to the rider to the control the speed of the bicycle! Later on, motors were

fitted to bicycles, and thus, mopeds came into existence. Further research and development led

to the invention of the motors car.

The steam engine and the rail road were invented in the 19th century. Apart from these,

motorized boats and ships were used as a means of water transport. Roads, rail road and water

remained the major means of transport for a very long time. The Wright brothers invented the

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 3

airplane and gave the world another means of transport - airways. In his effort to explore his

universe, man even stepped into space and invented the spaceship to travel in space.

There are various means of transport, such as road, rail, water and airways. The mode of

transport can be chosen, usually depending upon the distance to be travelled, but sometimes

also upon how fast you want to get to your destination.

Measuring Length and Distance

Various means of measurement, such as the palms, fingers, arm length and feet, were used to

measure length and distance before standardized systems were introduced. Standards needed

to be set to ensure consistency and to standardize measurements. Several systems were

devised, but almost the entire world now follows the metric system.

The base measurement for the pyramids is the cubit, which was formulated by the Egyptians. A

cubit was measured on the arm, from the point where the elbow bends, to the tip of the middle

finger. One cubit is equal to 18 inches. However, the inch was invented by the Romans.

In order to avoid confusion in measurements, the French created in 1970 the metric system,

which is a standard for measurement. A further development to ensure uniformity

measurement of lengths and distances, and other quantities, was a standard of measurement

called the International System of Units or SI.

The SI unit of length is the metre, and is denoted by the small letter 'm'. This is the basic unit of

length.

1 metre =100 centimetres

1 centimetre=10 millimetres

10 millimetres=1 centimetre

Large distances are measured in kilometres, and 1 km=1000 m.

The length and type of an object determines the kind of measuring tool one can use.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 4

Transportation and Distances

Walking was the first the means of transportation

Motion and Measurement of Distances

Walking was the first the means of transportation. Boats were used to transport goods on

water. Early boats were simple logs of wood with a hollow cavity. The invention of the wheel

revolutionized transport. Wheel design was improved over thousands of years.

Till the beginning of the 19th century, people depended on animals for transportation of

goods. Animals were used to pull vehicles that moved on wheels. Popular vehicles, like the

bicycle, were invented in the late 18th century. The first bicycles made did not have any brakes.

It was up to the rider to control the speed or stop the bicycle with his feet.

An exciting development was the fitting of motors on to bicycles. The steam engine and the

railroad, too, were invented in the 19th century. The invention of the steam engine introduced

a new source of power for transportation. Rail tracks were made for steam engine-driven

carriages and wagons to transport goods.

The Wright brothers invented the airplane, and that is when the era of flying began. Electric

trains, monorails, supersonic aeroplanes and spacecraft are some of the contributions of the

20th century. One of the most exciting developments in travel is the flying train. It's referred to

as the flying train because it doesn't touch the rails as it moves. Huge magnets keep the train

suspended in air.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 5

Before the metrics for measurement were developed, people used several different means to

calculate distance and length. For instance, a carpenter would measure the length of wood

using his palms, fingers or arm. Similarly, a cloth merchant would measure the length of cloth

against an outstretched arm. To standardize measurements and ensure consistency, standards

needed to be set.

Foot length or palm length were commonly used as non-standard units of measurement.

Historians say that the Egyptians formulated the cubit. The cubit was the base measurement

for the pyramids. The point from where your elbow bends to the tip of the middle finger of

your outstretched hand is the cubit.

However, scientists all over the world felt the need for uniformity in the standards for the

measurement of lengths and distances. Today, they all use a standard of measurement called

the International System of Units or SI units. The SI unit for length is the metre, and is denoted

by the small letter 'm.' For measuring large distances, as per SI standards, we use the kilometre,

denoted by two small letters 'km.' One kilometre is equal to 1000 metre.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 6

Measuring Length and its Accuracy

A ruler is used to measure the length of an object.

It is also used to measure the length of a straight

line.

A ruler is used to measure the length of an object. It is also used to measure the length of a

straight line. A non-stretchable string or thread is used to measure the length of a curved line.

Procedure to Measure the Length of an Object (or) a Straight Line

First place the ruler along the edge of the object that is to be measured, with the zero

mark of the ruler placed at one end of the object.

On the ruler, note the reading at the other end of the object.

This gives the measure of the length of the object.

The same procedure can be followed to measure the length of a straight line.

Procedure to Measure the Length of a Straight Line Using a Damaged Ruler

Place the broken or damaged ruler along the edge of the object that has to be

measured in such that any visible mark coincides with one end of the object.

Now note the reading on the ruler at the other end of the object.

The difference between the two readings is the length of the object.

Accuracy

Whatever method you use, always look at the ruler with the eyes directly in the line with the

reading and not in an oblique way to obtain the readings accurately.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 7

Procedure to Measure the Length of a Curved Line

Take a non-stretchable string or a thread and tie a knot at one of its ends.

Place the knotted end of the thread at one end of the curved line.

Holding the thread steadily with your fingers, and stretch it along the curved line until

you reach the other end.

Now make a mark on the thread where it reaches the other end.

Finally, place the thread along a metre scale and measure the length between the knot

and the marked point.

This gives the length of the curved line.

Length is one of the fundamental quantities. To measure the length of any object, place

a ruler along the edge of that object with the zero mark of the ruler placed at one end of

the object. Then, note the reading on the ruler at the other end of the object. This gives

the measure of the object's length. When noting the reading on a ruler, you should look

at it with the eyes directly above the reading, and not in an oblique way. Otherwise, you

will not be able to note the reading accurately. If the zero mark of the ruler does not

coincide with the first end of the object, then the difference between the readings at

the two ends gives the length of the object.

The circumference of a cap forms a curved line. To measure the length of a curved line,

tie a knot on one end of a piece of thread. This becomes the starting point for

measurement. Now, place this knotted end at the starting point of the curved line that

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 8

you want to measure. Then stretch the thread along the curved line, keeping it in place

with your fingers and thumb. Keep stretching the thread along the curved line until you

reach the end of the line. Use a pen to make a mark on the thread at the point where it

reaches the other end of the curved line. Now, place this thread along a metre scale and

measure the length between the knot and the marked point. This gives you the length

of the curved line, which is the edge or the circumference of the cap.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 9

Rest and Motion

When a body remains in one position for a long

time, it is said to be at rest.

Rest

When a body remains in one position for a long time, it is said to be at rest. For example, the

chairs of the dining table are at rest unless and until they are moved, and the flower vase, table,

and the blackboard in the class room are all at the position of rest.

Motion

The act, process or state of the change in place or position of a body with respect to time and

relative to the observer is said to be motion.

For example the blades of a rotating fan, the hands of a working wall clock, a moving car, a

spinning top and satellites are all in motion.

Rest and motion are relative terms

A body seems to be at rest with respect to one object, but may appear to be in motion with

respect to some other object.

For example, a person on a railway platform is at rest with respect to another person on the

same platform, but is in motion with reference to a person looking at him from a train crossing

that platform. Similarly, a passenger sitting in the train will appear at rest to another passenger

on the same train.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 10

Types of Motion

The various types of motion are

Rectilinear motion

Rectilinear motion is the motion of an object that moves in a straight line.

For example, a train moving on a track, a parade, coins tossed in the air are all in rectilinear

motion.

Circular motion

Circular motion is the motion of an object that moves at a fixed distance from a fixed point.

Here, all objects rotate in circular motion. So, circular motion is motion in which the body

traverses a circular path. The hands of a clock, a merry-go-round, the blades of a fan, the wheel

of a moving vehicle, satellites, a spinning top, are all good examples of circular motion.

Periodic motion

Periodic motion is motion that repeats itself at regular intervals of time. Every body executing

circular motion can be said to be executing periodic motion. For example, the pendulum of a

wall clock moves at regular intervals, the bells in a church, a bouncing ball, a vibrating string

and a swinging cradle are all in periodic motion.

Sometimes an object can display combinations of different types of motion:

For example

A moving car which moves straight on the road displays rectilinear motion but at the

same time the wheels of the car which are moving in circles display circular motion. So a

moving car displays both rectilinear and circular motion.

In a sewing machine, the needle is in periodic motion whereas the wheels of the sewing

machine are in circular motion. So a sewing machine displays circular and periodic

motions.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 11

If a body does not change its position with respect to time, then it is said to be at rest. If

a body changes its position with respect to time, then it is said to be in motion. There

are different types of motion. Rest and motion are relative terms. If you consider a

passenger in a moving train, he is at rest with respect to his co-passengers, but is in

motion with respect to an observer on the ground.

There are many examples of bodies that are relatively at rest. Trees, buildings and

mountains are some examples of bodies that are relatively at rest with respect to each

other. Some examples of bodies in motion are flying birds, moving trains, and the

rotating blades of a ceiling fan.

There are different types of motion. They are rectilinear motion, circular motion and

periodic motion.

Rectilinear motion

Rectilinear motion is the motion of a body in a straight line. Examples of bodies in

rectilinear motion are sprinters in a race along a straight track, the march-past of

soldiers in a parade, and a bullet fired from a gun.

Circular motion

When a body moves along a circular path, it is said to be in circular motion. Examples of

bodies in circular motion are the rotating blades of a fan, children playing on a merry-

go-round, and the hands of a clock.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 12

Periodic motion

When the motion of a body repeats itself after a certain time period, it is called periodic

motion. The motion of a pendulum in a pendulum clock, and the motion of needle in a sewing

machine are some examples of periodic motion.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 13

2. Light, Shadows and Reflections

Types of Media

Objects that emit light on their own are called

luminous objects

Luminous objects

Objects that emit light on their own are called luminous objects. The light emitted by luminous

objects enables us to see things around us. Examples of luminous objects are a tube light, the

sun, a lit candle, glowing bulb, a bonfire and a lit torch.

Non-luminous objects

Objects that do not emit light on their own are called non -luminous objects. The light emitted

by luminous objects falls on non-luminous objects, and then bounces back to our eye, which

enables us to see non-luminous objects. Examples of non-luminous objects are the moon, a

book, a pen, a wooden box, a cupboard and a chair.

Opaque objects

Objects through which we cannot see are called opaque objects. A medium that does not allow

light to pass through it is called an opaque medium. Examples of opaque medium are a pencil

box, a wooden screen, a book, a towel, a ceramic plate and chart paper.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 14

Transparent objects

If we are able to see anything clearly through an object, then such an object is said to be a

transparent object. A medium that allows all the light incident on it to pass through it is called a

transparent medium. Examples of transparent objects are plain glass, a reading glass, a plastic

scale, windowpanes, a soap bubble and pure water.

Translucent media

Objects that allow only a part of the light incident on them to pass through it are called

translucent media. Examples of translucent media are a shower stall, smoked glass, sun glasses

and butter paper.

Light travels in a straight line, and its rays represent the path of light

Objects like the sun that give out or emit light of their own are called luminous objects. Objects

like the moon and planets that do not give out or emit light are called non-luminous objects.

You can see objects when light from luminous objects incidents on them and reflects towards

your eyes. The material that light passes through is called a medium.

There are three types of media. They are transparent, translucent and opaque. Material that

allows the entire light incident on it to pass through is called a transparent medium. Examples

of transparent medium are clear glass and clear water.

Material that allows a part of the incident light to pass through it is called a translucent

medium. Examples of translucent medium are butter paper, tissue papers and ground glass.

Material that does not allow light to pass through it is called an opaque medium. Most objects

in our surroundings, like buildings and trees, are opaque objects.

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Shadows and Pin Hole Camera

An opaque object blocking the path of light is

called a shadow.

Shadow

An opaque object blocking the path of light is called a shadow. A shadow is a dark region, and is

formed only when a light source, an opaque object and a screen are present. For example,

during a lunar eclipse, we see a part of the earth's shadow on the surface of the moon. This

happens when the earth, the sun and the moon are in a straight line, with the earth between

the sun and the moon. Here, the sun acts as the light source, the earth as the opaque object,

and the moon as the screen. Opaque objects form shadows because light is not able to bend

around them.

Shadows are seen more clearly on light screens. Whatever the colour of the object, its shadow

is always black because it is not illuminated by light. The length and shape of a shadow

depends on the object by which it is formed. In the olden days, shadows caused by objects

placed in the sun were used to measure time. Such a device is called a sun dial. The Jantar

Mantar in Jaipur consists of a sundial or Samrat Yantra, which can be used to tell the time, as its

shadow moves visibly at one millimetre per second, or roughly six centimetres every minute.

Pinhole Camera

The image formed by a pinhole camera is inverted and smaller in size when compared to the

original object. These cameras work on the principle that light travels in a straight line. Pinhole

cameras are cheap and simple to make. An eclipse can be viewed using a pinhole camera.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 17

Making a Pinhole Camera

Take two rectangular boxes that fit into one another without leaving any gap.

Cut open one side of each box.

Make a small hole in the larger box at the centre of the closed end opposite the side

that has been cut open.

Cut a square of side five centimetres in the smaller box in the closed end opposite the

side that has been cut open. Cover this square with tracing paper.

Finally, slide the smaller box into the larger box, ensuring that the pinhole and the

tracing paper are in line with one another, but at the opposite ends.

Slide the smaller box to adjust the focus so that you can capture the image of any object

you want.

This is the basic structure of the pinhole camera. However, the developed form of a pinhole

camera uses photosensitive film instead of translucent paper to capture images. The film can be

developed later to obtain photo prints. Nowadays, of course, we use digital cameras that store

images in a computer chip. However, the basic principle of capturing the image remains the

same.

An area that is not or is only partially irradiated or illuminated because of the interception of

radiation by an opaque object between the area and the source of radiation is called a shadow.

Shadows take the form of the outline of the object that intercepts the light in its path. Thus, the

dark outline of the opaque object that you see is a shadow.

To form a shadow, we need a source of light, an opaque object in the path of light, and a screen

on which a shadow is formed.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 18

The shape of the shadow of an object is dependent neither on the colour of the object nor on

the colour of the screen.

If the distance of the object from the source is decreased, then the size of the shadow

increases, provided the distance between the source and the screen is constant. Maintaining

the distance of the screen from the source, if the object is moved away from the source, then

the size of its shadow decreases.

If the distance between the object and the screen is constant, and if the light source is moved

towards the object, then the size of its shadow increases. On the other hand, if the distance

between the object and the screen is constant, and if the light source is moved away from the

object, then the size of its shadow decreases.

Another factor affecting the size of the shadow is the distance between the object and the

screen. If the distance between the object and the source of light is maintained constant, and if

the screen is moved away from the object, then the size of the object's shadow decreases. On

the other hand, if the screen moves towards the object, then the size of its shadow increases.

The size and shape of the shadow of an object depends on the orientation of the object with

respect to the beam of light. The shadow changes in size and shape when the object is placed in

a different way in the path of light.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 19

Mirrors and Reflection

The likeness of an object carried and formed by

light in a mirror is called an image.

Image

The likeness of an object carried and formed by light in a mirror is called an image. For

example, your image is a reflection of your face in the mirror. An image can be seen in the

mirror because the light reflected from an object falls on the mirror and it is reflected. So, light

incident on any smooth shiny surface like a mirror bounces back into the same medium. This

bouncing of light by any smooth surface is called reflection of light. Mirrors change the

direction of light incident on them. The image in a plane mirror is the same size and colour as

that of the object. Moreover, the distance between the image and the mirror, is the same as

the distance between the mirror and the object.

Shadow

When an opaque object blocks the path of light, a shadow is formed. A shadow is a black dark

outline. Its length changes with a change in the position of the source of light. Shadows can be

seen only on a surface or a screen.

Two-Way Mirror

A glass that acts as a mirror on one side and plain glass on the other is called a two-way mirror.

A two-way mirror is used when you want to observe people without letting them know that

they are being watched, for example, by police or in psychological institutions.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 20

Pinhole Camera

Images formed by a pinhole camera are entirely different from the images that are formed by a

mirror. The image formed by a pinhole camera is inverted and smaller in size when compared

to the object. The image is also not clear. Moreover, the distance between the object and the

pinhole is not the same as the distance between the pinhole and the image.

A periscope is an instrument used for observing objects from a hidden position. This instrument

is mostly used in submarines, and works on the concept of reflection in plane mirrors. Using

mirrors, it enables people in a submarine to view objects on the surface of the water.

Reflection is the phenomenon in which light incident on an object bounces back into the same

medium through which it was propagating while incident on the object, following some laws.

The path along which light propagates is called a light ray. When a light ray is incident on an

object, it is called the incident ray. The ray that bounces back by the object into the same

medium called the reflected ray.

A smooth plane surface that reflects the entire light incident on it is called a plane mirror. Light

incident on an object is reflected by that object. That reflected light incidents on the mirror, and

is reflected again. It is because of this reflection that we see images. An image is the likeness of

an object carried and formed by light in a mirror. In other words, your image is a reflection of

your face in the mirror. In ancient times, people mostly used pools of still water, or water

collected in a vessel as mirrors. The first man-made mirrors were in the form of a polished

stone made by using obsidian, a naturally occurring volcanic glass.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 21

The similarity between a shadow and an image is that neither can exist without light. However,

there are some differences between shadows and images. Shadows are black, whereas images

are colourful. Shadows of objects placed in the sun change in length with the position of the

sun through the day. Your shadow will be at its longest at dawn or early morning, and at dusk

or early evening, whereas it will be at its shortest at noon. An image in a plane mirror doesn't

change in size at all; it is always the same size as that of the object. An image in a mirror can be

seen without a screen, whereas it is mandatory to have a screen to form a shadow.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 22

3. Electricity and Circuits

Electric Cell and Torch Bulb

An electric cell provides electricity to various

devices that are not directly fed by the supply of

electricity.

An electric cell provides electricity to various devices that are not directly fed by the supply of

electricity.

Electric Cell

An electric cell consists of two terminals. One is a positive terminal and the other one is a

negative terminal. A chemical that helps produce electricity to connected devices.

Bulb

A bulb consists two terminals. A filament is a spirally wound wire inside the bulb supported by

two thick wires at its ends. An electrical cell is connected to the terminals of a bulb so that

electricity from the cell can pass through the bulb. This electricity makes the filament in the

blub glow and emit light.

Electric Cell and Torch Bulb

An electric cell is a device that supplies electrical energy to devices that function using

electricity. Thus, an electric cell produces electricity for a torch to glow. In fact, not only a torch,

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 23

an electric cell provides electricity to a number of devices, such as toys, alarm clocks, pocket

radios and cameras.

An electric cell has a cap, just under which there is a plus sign. This is the positive terminal of

the cell. At the other end of the cell, there is a flat metallic disc with a minus sign just above the

disc. This metallic disc is the negative terminal of the cell. These terminals of the cell can be

used to connect it to various devices. Inside a cell, there is dark powdery stuff, which is the

chemical. This chemical helps the cell to provide electricity to the device it is connected to.

When a cell is connected to a device, the strength of the chemical decreases. Finally, when the

entire energy of the chemical is spent, the device connected to the cell stops functioning. A

rechargeable cell or a storage battery can be recharged

The bulb inside a torch has a filament. This filament is supported by two thick wires at its ends.

When the positive and the negative terminals of an electric cell are connected to the two

terminals of a bulb, electricity passes through the filament and it starts glowing. The terminals

of the bulb are fixed in such a way that they do not touch each other. The bulbs that we use in

our homes all look the same. In recent years, a different type of bulb has become popular - the

compact fluorescent lamp, generally referred to as a CFL. It is an energy-saving bulb, which has

a longer life than an ordinary bulb.

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Electric Circuit

Electricity needs a path to pass from the positive

terminal to the negative terminal of an electric

cell.

Electricity needs a path to pass from the positive terminal to the negative terminal of an

electric cell. A connection that provides a path outside an electric cell, for the electricity to

pass from the positive terminal to the negative terminal of the cell, is called an electrical

circuit.

For example, a bulb glows only when the positive terminal and the negative terminal of an

electric cell are connected to the two terminals of the bulb.

If the wires from the bulb are connected to the same terminal (either positive or negative),

then the bulb doesn't glow.

Sometimes, the bulb may not glow even though the connections are properly made.

This is because the flow of electricity is incomplete as the filament in the bulb is broken. A

broken filament bulb is said to be fused.

A device that is used to stop the flow of electricity by breaking the circuit is called a switch.

Switches have wide range of applications. Some common types are:

Toggle switches, which are used in our houses.

Pushbutton switches, which are used in the starter of a water pump.

Joystick switches, which are used in the remote control unit of a toy car.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 26

Electric Conductors and Insulators

All materials do not allow electricity to pass

through them.

All materials do not allow electricity to pass through them. Materials that allow electricity to

pass through them are called conductors. Conductors conduct electric current. Since metals are

good conductors of electricity, electric wires are made of metals. These electric wires act as

conducting materials. So they are used to make electrical circuits. Some common conductors

that conduct electric current are copper, silver, gold and aluminium. Copper is the most popular

material used for wires. Sometimes we receive electric shocks because our bodies are also

good conductors of electricity.

Materials that do not allow electricity to pass through them are called insulators. Insulators

oppose electric current and so they are used as protection from the dangerous effects of

electricity. Some common insulators are glass, air, plastic, cotton, thermocol, wood and rubber.

Water is a good conductor of electricity, but in its purest form, called distilled water, it acts as

an insulator. Distilled water is, therefore, used in batteries as an insulator.

We use various electrical appliances every day. Without the help of insulators, the use of

electrical appliances is impossible. The parts of the electric appliances that we touch are

covered with insulating material. For example, plugs and switches are covered with an

insulating material such as plastic, and the wire attached to the plug is a metal wire, which is a

conductor. So conductors and insulators work hand in hand.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 27

4. Fun with Magnets

Magnetic and Non-magnetic Materials

A Greek shepherd named Magnes discovered

magnets 4,000 years ago in Magnesia, Greece.

A Greek shepherd named Magnes discovered magnets 4,000 years ago in Magnesia, Greece.

The name magnetite has been derived from Magnesia or Magnes. Magnets are named after

Magnetite.

Magnets attract magnetic materials. Natural rocks that have the property of attracting iron are

called naturals magnets. Magnes discovered a natural magnetic rock, called the lodestone. In

the form of a bar, it was used to find directions on the earth, and so the name, 'lodestone,'

which means the stone that leads. Lodestone has a compound of iron called magnetite. These

natural magnets have the magnetic property of attracting materials like iron.

"Archimedes", the ancient Greek scientist, is believed to have used lodestone to pull nails from

enemy ships. Taking the nails out made the ships sink.

Magnetic Materials

Materials that are attracted by a magnet are called magnetic materials. Objects made of

materials such as iron, cobalt and nickel are magnetic objects. Examples of magnetic materials

include iron nail, key, metal spade, needle and metal door handle.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 28

Non-Magnetic Materials

Materials that are not attracted by magnets are called non-magnetic materials. Modern coins

are made of uniform mixtures of different metals so they become non- magnetic. Examples of

non-magnetic materials include rubber, coins, feather and leather.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 29

Properties of a Magnet

Substances that possess the property of

attracting iron are called magnets.

Substances that possess the property of attracting iron are called magnets. The two ends of a

magnet are called its poles. All magnets have two poles, and they are called dipoles. A magnet

with a single pole doesn't exist. Since poles have high magnetic power, they attract objects

easily. The poles of a magnet are named as the North Pole and the South Pole. In order to

identify the poles, the North Pole is usually painted in red colour. The other end of the magnet

will, therefore, be the South Pole. In laboratories, magnets are painted completely red in colour

with a white dot to indicate the North Pole. The other end will, therefore, be the South Pole. A

magnet can be cut into two pieces. Each piece will behave like an independent magnet, with a

north pole and a south pole.

Types of magnets

Bar magnets

In these magnets, the poles are located at the ends of the bar.

Cylindrical magnets

In these magnets, the poles are located at the two circular ends of the cylinder.

Dumb-bell shaped magnets

In such magnets, the poles are located at the two dumb-bell shaped ends.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 30

Horseshoe magnets

In these magnets, the poles are located at the two free ends of the 'U' shape.

Compass

A compass is an instrument that is used to find the directions. It has a thin magnetic needle

supported from a pivot so that it can rotate freely. The needle is placed over a dial with the

directions marked. The entire assembly is placed inside an airtight box.

The north pole of the magnetic needle is painted red. The magnetic needle in the compass

points in the north-south direction. By aligning the dial properly, the directions can be found. In

the ancient days, an old pointing device, called the south pointing fish, was used to know the

directions. The head of the fish pointed towards the south.

Alignment of a compass

Take a compass and make sure that the magnetic needle comes to rest. Rotate the box so that

the red tip of the magnetic needle coincides with the north mark of the dial. The compass is

now aligned. Next, select any object around you. Then, with the help of the compass, identify

the direction in which the object lies relative to you.

Law of magnets

Unlike poles attract each other and like poles repel each other.

Artificial magnets

Magnets can be made artificially, too. A rectangular iron bar, an iron needle, a blade or an iron

nail can be turned into a magnet by rubbing a bar magnet over it.

Precautions to protect magnets from losing their magnetic properties

Never drop magnets from heights.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Physics Chapter Notes Page 31

Never heat a magnet.

Do not hammer a magnet.

Certain items such as CD's, DVD's, debit cards, credit cards or ATM cards, audio and video

cassettes, and mobile phones contain magnetic material. Keep them away from magnets to

prevent damage.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Chemistry Chapter Notes Page 1

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Chemistry Chapter Notes

Chemistry Chapters as per NCERT Text Book Topics

1. Fibre to Fabric Fibres

2. Sorting Materials into groups Properties of Materials

3. Separation of Substances Methods of Separation I

Methods of Separation II

4. Changes Around us Changes around us

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Chemistry Chapter Notes Page 2

1. Fibre to Fabric

Fibres

Fabrics are made up of strands called

yarns, which are made from even

thinner strands

Fabrics are made up of strands called yarns, which are made from even thinner

strands,

called fibres.

Cotton, silk, wool and jute are called natural fibres as they are obtained from

natural sources. We get cotton and jute from plants. We get silk from the cocoons

of silk worms.

Synthetic fibres like nylon, polyester and acrylic were invented about a hundred

years ago. These are man-made and are not obtained from any plant or animal

sources.

Cotton fibre is obtained from cotton plants that grow in black soil in a warm climate.

In India, cotton is grown in Gujarat, Maharashtra, Andhra Pradesh, Punjab, Haryana,

Karnataka, Tamil Nadu, Rajasthan, Orissa and Madhya Pradesh.

The cotton plant bears fruits about the size of a lemon, called cotton bolls. The

bolls are full of seeds and cotton fibre. They burst open when they are ripe.

The cotton fibres are collected by hand from the ripe cotton bolls. This process is

called picking.

Next, the cotton fibres are separated from the seeds by combing them. This is

known as ginning.

Earlier, ginning was done by hand, but nowadays, a machine is used.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Chemistry Chapter Notes Page 3

Jute fibre comes from jute plants, which are mainly grown in places that have high

temperatures and plenty of rainfall. Jute is cultivated during the rainy season. In

India, jute is cultivated in West Bengal, Bihar, Andhra Pradesh, Uttar Pradesh,

Assam,

Chhattisgarh and Tripura.

The jute plant is generally harvested when it is in the flowering stage.

The stems of jute plants are soaked in water for a few days until they start

rotting.

Then the fibres are separated by hand from the rotting stems.

Once the fibres have been obtained, they are made into yarn by twisting the

strands together. This process of making yarn from fibre is called spinning.

Not just jute, even cotton, silk and other fibres are spun to convert them into yarn.

Machines are used for spinning yarn on a large scale. Fabrics like khadi are made by

spinning yarn on hand-operated devices like charkhas and taklis. The process of

arranging two sets of yarns to produce a fabric is called weaving. Even coconut

fibre can be woven into a fabric called coir. Coir is too rough to be made into

garments. It is mostly used to make doormats, carpets and other flooring

material.

In ancient Egypt, flax and cotton plants were cultivated near the River Nile and were

used for making fabric. At the beginning of civilisation, people used bark, leaves and

animal fur to cover themselves. As people settled down and started farming, they

learned to weave vines and animal fleece to make fabrics.

In the next stage of civilisation, flax and cotton were woven into garments. In those

times, people just draped the fabric to cover themselves. It was only after the

invention of the sewing needle that people started stitching their garments.

Even today, in older cultures like India, you see people wearing unstitched garments

like turbans, saris and dhotis.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Chemistry Chapter Notes Page 4

2. Sorting Materials into groups

Properties of Materials

Objects are categorised on the basis

of their shapes, the materials they are

made up of, and the properties of

these materials.

Objects are categorised on the basis of their shapes, the materials they are made up

of, and the properties of these materials.

All objects around you have definite shapes. For example, eggs are oval and

ice-cream cones are conical in shape. Objects can be classified on the basis of

their shapes.

Objects can be made from many different kinds of material, such as plastic,

wood,

glass, metal, cotton, paper, leather, wool, rubber, and even soil. Therefore, all

objects can be grouped on the basis of the material that they are made from.

Sometimes, the same object can be made from different materials.

For instance, a pen could be made from metal or plastic, your shoes could be made

from leather or cloth, and even the tumbler that we drink from could be made from

plastic, glass or metal. Bottles could be made from plastic or glass, and chairs could

either be wooden, metallic or plastic.

Notebooks, greeting cards, newspapers and calendars are all made from paper.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Chemistry Chapter Notes Page 5

Similarly, shoes, belts and bags that are made of leather form another group.

So, objects can be grouped according to the materials they are made of.

Gold, copper, iron and aluminium look shiny, and are called lustrous materials.

Most metals have this property. Other materials like wood or plastic, are non-

lustrous.

Metals like iron may react with the moisture in the air, which makes them lose their

lustre and look dull.

Iron is a good example of a very hard material. Materials that are considered

hard are difficult to compress, while those that can be compressed or scratched

easily are called soft materials. Cotton and sponge are examples of soft

materials.

Objects can be classified on the basis of properties of the materials that they are

made from.

Solubility is another important property of a material. Substances that completely

dissolve in water are said to be soluble in water. Substances like sand and

sawdust do not dissolve in water even if you stir them very well. They are said to

be insoluble in water. Some gases can dissolve in water. For example, oxygen

dissolved in water is useful for plants and animals that live underwater.

Lighter materials like paper, leaves and wood float on the surface of water,

while heavier objects, like those made from iron, sink in water.

Materials like glass or plastic are called transparent as you can see through

them. Objects made from transparent materials allow you to easily see what they

contain.

Materials like wood, cardboard and metal are opaque, as you cannot see through

objects made from these materials.

Some materials like plastic can be transparent or opaque, depending on the use for

which the object is meant.

For example, try spotting the jar that contains cookies from among these containers!

There are some materials that allow you to see through them, though not very

clearly. Such materials are called translucent. Butter paper and frosted glass are

examples of translucent material.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Chemistry Chapter Notes Page 6

Thus, there are various properties on the basis of which you can group objects.

Grouping is

useful for locating objects easily, such as on supermarket shelves. It also helps in

studying the

properties of objects that are in these groups.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Chemistry Chapter Notes Page 7

3. Separation of Substances

Methods of Separation I

There are various methods for

separating substances, such as

handpicking, threshing, winnowing

and sieving.

There are various methods for separating substances, such as handpicking,

threshing, winnowing and sieving.

Handpicking allows the good grains to be separated from the waste and

impurities.

Handpicking is the basic method for separation of substances. It involves simply

picking

out substances by hand and separating them from others. The substances being

separated may

be impurities that have to be thrown away. It could also be that both the substances

being separated are useful - such as separating green grapes from black ones.

The method of separating the grain from the stalk is called threshing. It is

basically the

beating of dry stalks to shake off the dried grains. It can be done by hand, by cattle

or by

machines. Traditionally, threshing was done by hand, but cattle help do the job

quickly.

Nowadays, threshing machines are also used to separate large quantities of grain

quickly.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Chemistry Chapter Notes Page 8

Even though the large stalks can be separated from the grains by threshing, the

grains still have dried husk and chaff, which have to be separated and thrown away

before the wheat can be used. This method is called winnowing.

The husk is blown away as it is much lighter than the grain. So, when the

grains are gently

dropped to the ground, only the wheat grains collect there, while the husk blows

away.

Sieving is a method of separating substances that are of different sizes. For

example,

wheat flour has some fine powdered wheat as well as some bigger impurities. When

it is put this through a sieve, the fine powder falls through the small holes in the

sieve, while the thicker

impurities remain as they are too big to pass through these holes. The substances

are thus separated.

Methods of Separation II

Grains can be separated from dirt by

sedimentation and decantation. When

water is added to the grains, the dust

and dirt dissolve in the water, making

it muddy.

Grains can be separated from dirt by sedimentation and decantation. When water is

added to the grains, the dust and dirt dissolve in the

water, making it muddy. Thus, the dirt and grains are separated.

The grains settle at the bottom because they are heavier.

This process of the settling of the heavier substance is called sedimentation.

Now, the grains can be separated by simply pouring out

the water. This process is called decantation.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Chemistry Chapter Notes Page 9

Oil and water can also be separated by decantation and sedimentation. Water is

heavier than oil, so it settles at the bottom if left alone for some

time. The oil can then simply be poured out.

The water left behind can be further cleaned using a filter paper. While water passes

through the fine pores of the filter, dirt will sift out, leaving the water clean.

This process of using a filter to separate substances is called filtration.

Salt and water from salty water can be separated by evaporation.

We need to boil this water so that its temperature rises and it converts into steam.

This process is called evaporation.

The steam turns back into water when it comes in contact with a

cold metal lid. This process is called condensation.

A mixture of sand and salt can be separated by combination of methods.

The first method is sedimentation and decantation. This mixture is put in water

and left for the sand to settle for some time. Then, we will decant the salty water,

which will separate the sand from the mixture.

Now the salt can be separated from the water by evaporation. The water will boil

away, leaving the salt behind.

So, the mixture of the sand, salt and water has been separated successfully using

a combination of sedimentation, decantation, evaporation and condensation.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Chemistry Chapter Notes Page 10

4. Changes Around us

Changes around us

Every day, we see different types of

changes around us, like day turning

into night, the season changing from

winter to summer

Every day, we see different types of changes around us, like day turning into night,

the season changing from winter to summer, melting of ice to water, cooking of

food, and so on.

Changes take place around us all the time. However, all changes are the same. We

get back the original substance in some, and can't get them back in others.

A reversible change is a change that can be undone or reversed.

o Melting is an example of a reversible change.

o Boiling, evaporation and condensation are all examples of reversible changes.

o For example, if you could capture all the steam that is made when a kettle

boils, you could turn it back into water by cooling it.

o Some other examples of reversible changes are the melting of ice, folding a

paper and blowing a balloon.

o A blacksmith changes a piece of iron into different tools. For that, a piece of

iron is heated to red hot. This also softens it. It is then beaten into the desired

shape. It is a reversible change.

An irreversible change is a permanent change that cannot be undone. In an

irreversible change, new substances are formed.

Cake batter is made from eggs, flour, sugar and butter. Once the cake has been

baked, you cannot get the ingredients back.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Chemistry Chapter Notes Page 11

Heating a substance can cause an irreversible change.

Cooking is another example. We cannot get back the substances that we

originally started with

Mixing substances can also cause an irreversible change.

For example, when vinegar is mixed with bicarbonate of soda, you can observe the

release of

carbon dioxide gas in the form of bubbles. Again, here, we cannot get back the

original substances.

Some other examples of irreversible changes are the digestion of food and

heating of lime stone.

The burning of wood is also an irreversible change. Once wood is burned, it

changes to ash, and we cannot get back the wood again.

Finally, our growth itself, as you can see, is an irreversible change.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 1

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes

Biology Chapters as per NCERT Text Book Topics

1. Food: Where does it Come from? Sources of Food

2. Components of Food Test For Starch, Proteins and Fats

Nutrients and Balanced Diet

Deficiency Diseases

3. Getting to Know Plants Categories of Plants

Parts of a Plant

Parts of a Flower

4. Body Movements Joints and their Types

Bones and Skeleton

Gait of Animals

5. The Living Organisms and their Surroundings Habitat and Adaptation

Types of Habitat

Characteristics of Living Things

6. Water Water Cycle

Effects of Rainfall - Draughts and Floods

7. Air Around Us All about Air

8. Garbage In, Garbage Out Garbage Disposal and Vermicompost

Recycling Paper and Plastics

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 2

1. Food: Where does it Come from?

Sources of Food

All ingredients is a component of a

mixture

All ingredients is a component of a mixture.

Certain food items are made with few ingredients, but some are made with many ingredients.

Some ingredients are common for several food items.

Vegetables, cereals, pulses, fruits and spices come from plant sources.

Mean, poultry, fish and milk products come from animal sources.

Animals are categorized based on their eating habits into herbivores, carnivores and omnivores.

Herbivores are animals that eat only plants and plant products.

Carnivores are animals that eat meat.

Omnivores eat both plants and animals.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 3

2. Components of Food

Test for Starch, Proteins and Fats

Different food items contain different

types of nutrients

Different food items contain different types of nutrients.

Nutrients are chemical components in food that are required for releasing energy and helps in

growth.

Carbohydrates, proteins, fats, vitamins and minerals are important nutrients found in food.

Carbohydrates and fats mainly provide energy.

Proteins mainly help in growth.

Starch and sugar are the two kinds of carbohydrates found in food.

To test the presence of starch in a food item, you need to:

Take small quantity of the food items to be tested.

Put 2-3 drops of iodine solution on it.

Observe the colour of the food item.

Blue-black colour indicates the presence of starch in the tested food item.

To test for the presence of proteins in a food items, you need to:

Take a small quantity of the food items to be tested.

Grind/mash/paste/powder the food item.

Put the food item into a test tube.

Add 10 drops of water to the test tube.

Add two drops of copper sulphate solution to the test tube.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 4

Add 10 drops of caustic soda solution and shake the test tube.

Observe the colour of the mixture.

Violet colour indicates the presence of proteins in the tested food item.

To test for the presence of fats in a food item, you need to:

Take a small quantity of the food item to be tested.

Wrap the food item in a small piece of paper.

Crush the food item wrapped in the paper.

Straighten the paper.

Dry the paper by keeping it in sunlight for a while.

Observe the paper.

An oily patch on the paper indicates the presence of fats in the tested food item.

Nutrients and Balanced Diet

All living organisms require food. Food

has six types of nutrients - carbohydrates,

proteins, fats, vitamins, minerals and

water.

All living organisms require food. Food has six types of nutrients - carbohydrates, proteins, fats,

vitamins, minerals and water.

These are essential to perform all daily and metabolic activities.

Carbohydrates are compounds of carbon, hydrogen and oxygen, always in the ratio of 2:1:1.

They are oxidised in the cells to release energy. Carbohydrates include sugars, starch and

cellulose.

Carbohydrates are oxidised in the body in the form of sugars. They provide instant energy.

When oxidised in the body, one mole of glucose releases 686 kilocalories of energy.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 5

They are mainly present in rice, potato, banana, etc.

Proteins are composed of carbon, hydrogen, oxygen and nitrogen.

Nitrogen is the most essential element in proteins. Some proteins contain sulphur and

phosphorus.

Amino acids are the simple, smaller units of proteins. Proteins provide chemical material for

the growth and repair of the body cells and tissues.

In an emergency, they may also oxidize to release energy. Food rich in proteins includes lean

meat, fish, eggs, milk, cheese, nuts, beans, peas, etc.

Fats are also composed of carbon, hydrogen and oxygen. Fats have very little oxygen content,

though..

They produce more energy than carbohydrates do.

Fat below the skin protects the body against rapid loss of heat.

It serves as a solvent for fat-soluble vitamins.

It is an important form for storage of food.

Common foods rich in fats are butter, cream, vegetable oils, meat, and fish liver oils.

Mineral salts are needed in the diet in small quantities. These are obtained from table salt, green

vegetables and fruits. Some important minerals are:

Calcium, required for:

Strengthening bones and teeth

Blood clotting

Muscle contraction

Rich sources: Milk, meat, eggs, fish, pulses, vegetables, etc.

Phosphorus, required for:

Strengthening bones and teeth

For production of ATP in during cellular respiration

Conduction of nerve impulses

Rich sources: Milk, meat, eggs, fish, pulses, vegetables, etc.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 6

Iron, required for:

Forming haemoglobin

Rich sources: Green leafy vegetables, liver, etc.

Iodine, required for:

Proper working of thyroid

Rich sources: Vegetables, mineral water and iodized salt

Vitamins are chemical substances that help maintain a healthy body.

Vitamins A, D, E, and K are fat soluble and can be stored in the body.

Vitamin B complex and vitamin C are water soluble and cannot be stored for a long period of

time.

Vitamin A: Promotes growth, vision.

Present in butter, egg yolk, milk, carrot, etc.

Vitamin D: Helps the body to absorb calcium and phosphorus to form bones and teeth.

Present in fish liver oils, milk, eggs, etc.

Vitamin E: Prevents the oxidation of vitamin A.

Present in meat, milk, whole wheat, etc.

Vitamin K: Helps in clotting of blood during injuries.

Present in cabbage, spinach, leafy vegetables

Vitamin B complex: Needed for a healthy brain, nerves and muscles.

Present in wheat, rice and liver.

Vitamin C: Helps fight diseases like the common cold.

Present in oranges, tomatoes, lemons and guavas.

Water: Helps the body to get rid of toxic wastes through urine and sweat, and to absorb the

nutrients in food.

Balanced diet: The diet that contains all the principle constituents of food in proper quantity.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 7

Deficiency Diseases

Occurs mainly due to the deficiency of one

or more nutrients in the diet over a long

period of time.

Diseases or disorders occur mainly due to the deficiency of one or more nutrients in the diet

over a long period of time. For example, wheat is rich in carbohydrates, but poor in nutrients like

proteins and fats. Too much intake of wheat products results in a deficiency of proteins and fats,

which reduces growth. Lack of proteins also results in stunted growth, skin diseases, swelling of

the face and discolouration of the hair, and even causes diarrhoea. So a balanced diet is required

to avoid deficiency diseases.

Diseases caused by deficiency of minerals:

Lack of iron in the diet leads to a deficiency disease called anaemia. The symptoms of anaemia

are headache, dark patches under the eyes, weakness and feeling tried. A balanced diet should,

therefore, include iron-rich foods such as apples, fish and raisins to avoid anaemia.

Lack of iodine in the diet leads to a deficiency disease called goitre. In adults, goitre results in

swollen glands at the throat. In children, iodine deficiency causes stunted mental and physical

development. Iodine deficiency can be avoided by using iodized salt in the diet.

Diseases caused by deficiency of vitamins:

Lack of vitamin A in diet causes loss of vision. Symptoms include night blindness, i.e. poor

vision in dim light. Eating food rich in vitamin A, such as carrot, mangoes, butter and egg yolk,

helps avoid loss of vision.

Lack of vitamin B1 in the diet causes a deficiency disease called beriberi. The symptoms are

loss of weight and weak muscles. Food rich in vitamin B1, such as beans, meat, eggs and corn,

helps avoid beriberi.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 8

Lack of vitamin C in the diet causes a deficiency disease called scurvy. The symptoms of scurvy

are bleeding gums. Moreover, wounds take longer to heal. Oranges, tomatoes, lemon, guavas and

amla are rich in vitamin C, so eating these helps avoid scurvy.

Lack of vitamin D in the diet causes a deficiency disease called rickets. The symptoms are soft

and bent bones. The diet should include fish, eggs, milk and butter to avoid rickets. In addition,

exposure to sunlight produces vitamin D in the body.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 9

3.Getting to Know Plants

Categories of Plants

A herb is a non-woody plant that has green

and tender stems with few branches and is

usually short

A herb is a non-woody plant that has green and tender stems with few branches and is usually

short.

Herbs have a variety of uses including adding flavor to food, providing medicine for diseases and

in some cases even adding a spiritual touch.

Shrubs are taller than herbs and have stems branching out from the base.

The stems of shrubs are hard not but thick.

A common place where shrubs are grown is known as shrubbery.

A tree is a woody plant that has many branches on a single stem.

Trees benefit us by preventing soil erosion, maintaining the carbon dioxide content in the air and

in building huts and making furniture.

Threes are categorized based on their height, width of their trunk, their overall size, and of course

their age.

Creepers are plants with weak stems and hence cannot stand straight. They grow on the ground.

Creepers have a tendency to develop new plants on their own.

A few creepers could cause allergies or skin problems if touched.

Climbers are plants that need support from other structures to grow and spread.

Climbers can either move horizontally or vertically unlike creepers that move only horizontally.

Climbers attracts insects and reptiles because of their brightly coloured flowers and fragrance.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 10

Parts of a Plant

The different parts of a plant are the roots,

stem, leaves, flowers and fruits.

The different parts of a plant are the roots, stem, leaves, flowers and fruits.

The roots of a plant are mostly seen underground and look brown in colour.

The tiny thread-like structures over the roots are the root hair. The tip of the root is called the root

cap.

Roots are of two types - tap root and fibrous roots.

Some plants have a primary root that grows more or less straight down into the soil, and is

tapered

towards the end. This main root is called the tap root.

There are many smaller roots that branch out from the tap root, called lateral roots.

Examples of plants with tap roots are hibiscus, carrot, turnip and sunflower.

Some plants have many lateral roots that start from the base of the stem.

These are called fibrous roots.

Examples of plants with fibrous roots are banana, grass and onion.

The roots hold the plant firmly in the soil, thereby serving as an anchor to the plant.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 11

One of the main functions of the roots is to absorb water and nutrients from the soil for the

growth of the plant. Sometimes they also store sugars and carbohydrates.

The stem holds the leaves, flowers and fruits in a plant.

The vascular tissue inside the stem helps to transport water and nutrients from the roots to the

leaves, and food from the leaves to the roots.

Plants release excess water in the form of water vapour through minute openings in the leaves,

called the stomata. This process is known as transpiration.

The different parts of a flower include sepals, petals, stamen and pistil.

The green leaf-like parts surrounding the bud are called the sepals.

The brightly coloured parts of a flower are called the petals.

The male part of a flower is called the stamen, and the female part is called the pistil.

The male and female parts of a flower are involved in the formation of fruit in a process called

fertilization.

Parts of a Flower

The flower is the reproductive part of a

plant.

The flower is the reproductive part of a plant.

The parts of a flower include sepals, petals, stamen and pistil.

The hard, leaf-like structures around the base of a flower are called its sepals.

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They protect the bud before it blooms into a flower. The sepals are collectively called the calyx.

The number of sepals varies from plant to plant.

The brightly coloured portions of a flower that attract insects and birds for pollination are called

petals.

Like sepals, the number of petals also varies from plant to plant.

The petals are collectively called the corolla.

In some flowers, the petals and sepals combine to form a round shape, which is called the tepal.

The stamens and the pistil are the reproductive parts of a flower.

The stamen is the male reproductive part of a flower.

The small tube with a little bulge at the end of a stamen is called the filament.

The filament has a yellow sac called the anther.

This yellow sac contains pollen grains, which contain male reproductive cells.

Like sepals and petals, every flowering plant differs in the number of stamens, too.

The female reproductive part of a flower is the pistil.

It consists of three parts - the stigma, the style and the ovary.

The upper end of the pistil is called the stigma, where pollen grains get deposited and

enter the pistil.

The narrow tubular part is called the style, which connects the stigma to the lower part of

the pistil.

The lower bulgy part of the pistil is called the ovary. It contains ovules.

The ovary can be cut longitudinally or transversely to see the female reproductive cells, ovules,

which appear as bead-like structures.

The number and arrangement of ovules differ in different flowering plants.

Like the stamens, the number of pistils also varies from flower to flower.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 13

4. Body Movements

Joints and their Types

The point at which two separate bones meet

is called a joint.

The point at which two separate bones meet is called a joint.

There are four types of joints in the human body.

They are:

Ball and socket joint: One end of a bone is rounded and ball-like, and fits into a cup-like

depression of the other bone.

This joint provides movement in any direction.

Shoulder joints and hip joints are examples.

In the shoulder joint, the head of the humerus fits into a socket of the shoulder girdle.

In the hip joint, the large ball-like head of the femur fits into the deep socket of the hip girdle.

Hinge joint: This joint moves like a hinge in one plane only, just like the hinge of a door.

The elbow joint between the humerus and the ulna.

The joints between the bones of the fingers and toes, and less perfectly, the knee joint.

Hinge joints usually give sufficient power, because there is less danger of twisting at the joint.

Pivot joint: One bone rotates over a pivot-like end of the other bone.

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The skull rotates on the upper end of the back bone.

Fixed Joint: In this joint, no movement is possible between the two bones.

The sutures between the bones of the cranium are an example.

Bones and Skeleton

The skeleton is a framework of all the bones

in the human body

The skeleton is a framework of all the bones in the human body.

The skeleton consists of the skull, hand bone, shoulder bone, rib cage, pelvic bone, backbone, leg

bone and cartilage.

The skull protects the brain.

The shoulder has the ball and socket joint that helps the arm swing.

The rib cage protects the lungs, heart, stomach, abdomen and liver.

The backbone runs from the top of the skeleton to the bottom of the skeleton. It is connected to all

the bones.

The pelvic bone protects the lower abdominal organs such as the urinary bladder, rectum and

uterus.

Cartilage is a soft bone tissue that connects joints. It is present in external parts like the ear and

nose.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 15

Gait of Animals

Earthworms move easily on hard and

slippery surfaces.

Gait of earthworms

Earthworms move easily on hard and slippery surfaces. Earthworms have tiny, stiff hair-like

projections, called bristles, under their body. They grab the soil with the help of these bristles.

Earthworms first stretch and then contract their muscles to move. As a result, they cover only a

small distance with every move. A slimy substance secreted by the earthworm helps it to move.

Earthworms eat their way through the soil. They throw away undigested food, which improves

the quality of the soil.

Gait of snails

The outer skeleton of the snail, the shell, is made of calcium carbonate. The snail pulls this shell

along as it moves. The snail can even hide its head inside the shell. The strong muscular foot

below the shell can protrude.

The under surface of the muscular foot is lubricated with mucus. Waves of muscular contractions

along this surface help a snail move. The mucus also reduces the risk of injury from sharp

objects. That is why snails can walk over sharp objects like blades without getting hurt.

Gait of cockroaches

The cockroach has three pairs of legs that help it to walk, and two pairs of wings that help it to

fly. A cockroach moves its legs with the help of muscles near the limbs. It uses its breast muscles

help to move its wings and fly. A cockroach can walk, fly and even climb. A cockroach can move

in different terrains like sand and wired meshes because of the spines on its legs.

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Gait of birds

A bird has a body best suited for flying. Its wings are actually modified forelimbs. Birds can fly

easily with the help of these bony forelimbs. Birds have light and hollow bones. The breast bones

hold the muscles of flight that help them to flutter their wings. The tail controls the direction of

flight. Birds have very strong shoulder bones. They don't have the urinary bladder, which helps

them to fly easily. They can walk and perch on trees with the help of their hind limbs.

Gait of snakes

Snakes move in S-shaped loops and in a zigzag manner. They cannot move in a straight line.

They have difficulty in moving on very smooth surfaces. Snakes have a long back bone and

many interconnected muscles that help them to slither. They have muscles connecting the

backbone, ribs and skin. Snakes move in grass, sand and water. Snakes do not have arms or legs,

but even then, they can climb trees.

Gait of fish

Fish have a streamlined body, which helps them move fast in water.

Fish swim with the help of their fins. The tail moves from side to side, and helps the fish swim in

the right direction. Some fish, however, move by bending their bodies from one side to another in

quick succession, which produces a thrust that helps it move forward.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 17

5. The Living Organisms and their

Surroundings

Habitat and Adaptation

Livings things exist in most places. Life

exists even in open volcanoes.

Livings things exist in most places. Life exists even in open volcanoes. The term habitat refers to

the surroundings where organisms live. Every habitat is home for a certain living creature.

Habitat includes both living and non-living components. Plants and animals have different

features that help them to survive in their own habitat. Habitat can be terrestrial or aquatic.

Terrestrial habitat refers to the land where all plants and animals survive. It includes deserts,

forests and grasslands, as well as coastal and mountain regions. For example, camels and cactus

plants live in deserts only.

Aquatic habitat refers to the water where plants and animals survive. Aquatic habitat includes

rivers, ponds, lakes, ocean and swamps. For example, fish live in water.

Adaptation: Plants and animals develop certain features or certain habits that help them survive

in their surroundings, and this is known as adaption. Different living creatures adapt to their

habitats in different ways. For example, fish have gills that help them to live in water and use the

oxygen dissolve in it. Plants that live in water have special tissues that help to take in dissolved

gas from water. For example, the ulva has ribbon-like leaves.

It takes thousands of years for a livings being to adapt to its habitat.

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Acclimatization: The small adjustments by the body to overcome small changes in the

surrounding atmosphere for a short period of time are called acclimatization.

The components in a habitat are broadly classified into two types. They are biotic and abiotic

components.

Biotic components include all the livings organisms in a habitat.

Abiotic components include all the non-living things in a habitat. These include air, rocks, water,

sunlight and heat. All livings things depend on the abiotic components for all their needs. The

abiotic components are very useful for the survival of the biotic components in a habitat.

For example, sprouting is the first step where a new plant grows from a seed. The sprouting of a

seed depends on abiotic components such as air, water, light and heat.

The population of some species of turtles has declined due to the change in the earth's

temperature. Some popular theories believe that dinosaurs became extinct because of the changes

in the earth's temperature millions of years ago.

Types of Habitat

Habitat is the place that is natural for the life

and growth of an organism.

Terrestrial Habitat

Habitat is the place that is natural for the life and growth of an organism.

Now let us discuss how animals and plants adapt themselves for the terrestrial and aquatic

habitats.

Terrestrial habitat: All the deserts, mountains and forests and plain lands has come under

terrestrial habitat.

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Camels have long legs for adaptation.

Snakes and rats live in burrows and come out only during the night when it is cool.

Xerophytes or desert plants shows some adaptations to sustain in the desert conditions.

In desert plants, the leaves are either absent or reduced to spines as in cacti.

The leaf-like structure seen in cactus is its stem and it carries photosynthesis.

The roots grow deep into the soil for absorbing water.

The reduced leaf and the thick waxy layer of stem minimize transpiration.

The plants and animals in the mountain habitat show some adaptations.

Most of the trees in cold mountains are cone shaped.

The leaves are also very thin and look like needles

For the sliding of water and snow during rains and snowfall.

Animals in mountain areas have long hair and thick skin to protect them from cold climate. Thick

fur all over Bodies of Yak and Snow Leopard protects them from the cold climate.

The mountain goat, have strong hooves that help them run on the mountain slopes easily

The animals living in the grasslands show some adaptations.

Lions live in forests and prey on other animals, like deer, for food.

The lions brown skin colour blends easily with the colour of dry grass in grasslands and helps in

the catching the prey.

They have strong claws to tear and eat their food.

The eyes of the lion in front of its head helps in identifying the prey from long distances.

Deers have long ears to help them sense the presence of a predator.

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Deers have eyes on the side of its head to look in all directions for danger and have long legs to

run away from predator.

Aquatic Habitat

All the fresh water and marine water bodies , has come under terrestrial habitat.

Fish have special features that help them to live in water.

They have streamlined bodies, which reduce friction and allow them to move freely in water.

Sea animals like the octopus and the squid do not have streamlined body as they stay deep inside

the ocean on the ocean bed, but make their body streamlined when they move in the water.

Sea animals, like fish, octopus and squid have gills that help them to absorb the dissolved oxygen

from the water they drink!

Dolphins and whales have blowholes to breathe in air when they swim close to the surface of the

water and there by stay inside the water for a long time without breathing.

In general the aquatic plants have much smaller roots and helps the plant in holding on the

surface. Stems are long and light.

Submerged plants such as Ulva has narrow and ribbon-like leaves. These allow the plants to bend

themselves in the direction of the flow of water.In milfoil, leaves are highly dissected, making

water to easily flow without Frogs usually live in ponds and lakes.

A frog can live both in water and on land. Frogs have strong hind legs to hop on land and webbed

feet to swim in water.

Frogs also have a membrane called the nictitating membrane on their eyes.

This membrane helps protect their eyes inside water.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 21

Characteristics of Living Things

Human beings, animals and plants - all need

food to survive.

Human beings, animals and plants - all need food to survive. Trees, creepers, birds, flowers,

insects, animals and seeds are all livings things. Soil, bench, water, air and dry leaves are all non-

livings things. The characteristics of livings things are:

Livings Things Need Food

Livings things need food to survive and grow. Food makes the body grow faster, and gives

energy to the body to help it perform the life activities. For example, plants produce their own

food by the process of photosynthesis, and grow. Animals depend on plants and other food for

their survival.

Livings Things Grow

As livings things take food, they get more and more energy and grow faster. All living things

grow continuously.

Livings Things Respire

Respiration is the process of breathing in and out. Living things take oxygen into the body as they

breathe in and release carbon dioxide as they breathe out. The oxygen that enters the body

during respiration helps the body to create energy from the food consumed. Some animals have

special organs that help them in the process of respiration.

For example, the gills of fish help them to absorb oxygen dissolved in water. Earthworms breathe

through their skin. Plants have tiny pores on the leaves that help them to breathe.

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Plants respire day and night, but breathe out oxygen during the day. Plants release more oxygen

while producing their food than they release during respiration.

Livings Things Respond to Stimuli

Stimulus is a change of some kind in the environment of a living organism. Every living thing

responds in some way or the other to stimuli. The response in plants to stimulus can be observed

easily.

Characteristics of Living Things

Human beings, animals and plants - all need

food to survive.

Human beings, animals and plants - all need food to survive. Trees, creepers, birds, flowers,

insects, animals and seeds are all livings things. Soil, bench, water, air and dry leaves are all non-

livings things. The characteristics of livings things are:

Livings Things Need Food

Livings things need food to survive and grow. Food makes the body grow faster, and gives

energy to the body to help it perform the life activities. For example, plants produce their own

food by the process of photosynthesis, and grow. Animals depend on plants and other food for

their survival.

Livings Things Grow

As livings things take food, they get more and more energy and grow faster. All living things

grow continuously.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 23

Livings Things Respire

Respiration is the process of breathing in and out. Living things take oxygen into the body as they

breathe in and release carbon dioxide as they breathe out. The oxygen that enters the body

during respiration helps the body to create energy from the food consumed. Some animals have

special organs that help them in the process of respiration.

For example, the gills of fish help them to absorb oxygen dissolved in water. Earthworms breathe

through their skin. Plants have tiny pores on the leaves that help them to breathe.

Plants respire day and night, but breathe out oxygen during the day. Plants release more oxygen

while producing their food than they release during respiration.

Livings Things Respond to Stimuli

Stimulus is a change of some kind in the environment of a living organism. Every living thing

responds in some way or the other to stimuli. The response in plants to stimulus can be observed

easily.

For example, a plant called touch-me-not closes its leaves when touched. Also, the Evening

Primrose blooms only during the night, while the flowers of Mentzelia Mollis close after sunset.

Livings Things Excrete

The process of eliminating wastes from the body is called excretion. Livings things need food,

but they only absorb some amount of it for various processes, while the remaining food needs to

be eliminated from the body. For example, plants eliminate harmful waste substances in the form

of secretions such as resins and gums, whereas some plants store the harmful substances without

any difficulty.

Livings Things Reproduce

All livings things reproduce. Some animals lay eggs, while others reproduce by giving birth to

young ones. Plants produce seeds that can germinate into a new plant, but there are some, such as

potato and rose plants, which reproduce through other parts.

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Livings Things Move

Even though plants are livings things, they cannot move as their roots are fixed in the soil.

However, the substances produced and required for their growth, such as water, minerals and

food, move from one part of a plant to another. Some plants show some restricted movement.

Animals have various modes of locomotion.

Livings Things Die

All livings things must die one day or another. Plants and animals die.

All livings things possess these characteristics, whereas non-livings do not have these

characteristics.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 25

6. Water

Water Cycle

Our Earth is covered by two-thirds of water,

but most of the water is not portable and

contains salt

Our Earth is covered by two-thirds of water, but most of the water is not potable and contains salt.

Water is used for various activities such as agriculture, industries, cooking, cleaning utensils,

bathing, washing clothes, and, most importantly, for drinking.

Ponds, wells, streams, lakes and rivers are the different sources of drinking water.They are

supplied water by the oceans and seas.Oceans and seas supply water to other water bodies

through the water cycle.

The circulation of water from the oceans and the surface of the earth, to the air as water vapour,

and its return to the ocean as rain, hail or snow, is called the water cycle

A variety of salts, like sodium chloride, calcium, magnesium and potassium, are present in saline

water. The evaporation of water takes place in the water cycle, leaving the salts behind in the

ocean.

The water present on the surface of the ocean evaporates by the sun's heat. This process of

conversion of water from liquid state to vapour state is called evaporation. The sun warms up the

surrounding air as well. Evaporation takes place faster in direct sunlight, than in a shady area.

Evaporation also takes place from wet clothes, fields, ponds, lakes and rivers.

Plants take in water to grow as well as to prepare their food.

They retain the water they need and release the excess water into the air as water vapour through

the stomata of the leaves and the stem. This process is called transpiration.

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Thus, water is mainly evapo-transpirated to the air from land, water bodies and plants.

The evaporated water is carried away by warm air.As the warm air moves higher from the surface

of the Earth, it starts to cool down. It is because the water vapour present starts to condense to

form tiny water droplets. These droplets float in the air and form cloud and fog.

All these droplets collect to form bigger drops of water. Some of them may become too heavy to

remain in the sky and fall down as rain. This process is known as precipitation.

If the air is too cold, the water drops can become snow or hail and may settle on the top of a

mountain. When these snow or hail melts, they can become part of a river or a stream. Thus, the

water that is evaporated from the oceans or seas is again condensed to form water and fills up the

rivers and seas. Rain water also seeps into the ground to form ground water.

This circulation of water is called the water cycle.

Effects of Rainfall - Draughts and Floods

Water is used in our day to day life.

Uses of Water

Water is used in our day to day life. Water is used for everyday needs such as brushing, bathing,

washing, cleaning etc. Farmers use ground water to water their fields.

Many industries use ground water to produce everything from paints and fabric to leather and

chemicals. So ground water is used for many purposes. Moreover the decline in the number of

trees, excess usage of water and the presence of concrete in the areas does not allow the rain

water to seep into the ground which is the reason for the shortage of water.

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Droughts

Due to lack of rains the wells, lakes, ponds get dried up and thereby creating water scarcity and as

result droughts are possible. If there are no rains, then the soil becomes more dry and patchy.

Droughts occur when there are no rains for a longer period of time. There is less rainfall because

trees are cut down. Droughts results in drying up of the crops and vegetation and this effects the

availability of food for villages and food for the other animals. Finally this leads to malnutrition

in humans.

Floods

Due to heavy rainfall the water levels in ponds, lakes rises to a greater extend and the rise in the

water level of these water bodies causes the excess water to spread across causing floods.

Floods wash out the living beings such as fish and other animals etc. and they create great havoc

to the mankind. Once the rains stops the flood water receded, fish, cattle and other animals were

left dead. Floods cause lot of harm to the living beings and there will be loss in property

also.

Rain Harvesting

Harvesting is a method to collect rain water and store the rain water. The purpose of harvesting

rain water is that two thirds of the earth is covered with water. Ocean and sea water contains

many dissolved salts and cannot be used for drinking, agriculture and domestic purposes.

So constant use of ground water results in scarcity of groundwater. So rain harvesting clears the

problem of depleting the ground water.

Technique involved in rain harvesting

First collect the rain water at the rooftop and then allow the rain water to travels through the pipes

or drains and then attach a wire mesh to the mouth pipe which filters large fragments such as

leaves etc.

This water is transported to the water tanks. These tanks contain layers of sand, gravel, charcoal

that will filter the dirt and other impurities from rain water. The water stored in the tank will then

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 28

be transported to an underground pit which will help water to seep back into the ground. Rain

harvesting solves the problem of depleting the ground water and droughts.

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7. Air around Us

All about Air

Air supports life on earth

Air supports life on earth.

Air helps in the scattering of seeds and pollens of plants.

Animals use air for respiration.

Plants use air to prepare their food.

Air is present everywhere.

Atmosphere is a thin layer of air surrounding the earth.

The atmosphere is dense at the surface of the earth and becomes thinner as one moves up.

Air is:

Transparent

Colourless

Occupies space

The movement of air is called breeze or wind depending on its velocity or speed.

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The following are the various components of air:

Nitrogen

Oxygen

Carbon dioxide

Water vapour

Smoke and dust particles

Nitrogen

Is the major component of air

Does not support burning

Oxygen:

Is the second largest component present in air

Supports burning

Smoke and dust particles present in air are harmful for the body.

Animals and humans breathe in oxygen and give out carbon dioxide during respiration.

Plants taken in carbon dioxide present in the atmosphere to make food and release oxygen into

the atmosphere.

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 31

8. Garbage In, Garbage Out

Garbage Disposal and Vermicompost

A large, low-lying area used to dispose

garbage is known as a dump. A garbage

dump is also used as landfill.

Garbage Disposal

A large, low-lying area used to dispose garbage is known as a dump. A garbage dump is also used

as landfill. Garbage collectors collect waste and then dispose it at garbage disposals. Garbage

dumps have flies, cockroaches and mosquitoes, and later turn into breeding grounds for micro-

organisms that may cause diseases. That is why these garbage dumps are usually located on the

outskirts of a city. When garbage mixes with soil, it takes a longer time to decay. The soil

becomes loose and a building cannot be constructed on such a landfill. Moreover, it takes 20 to

30 years for the soil to get ready for construction.

Components of garbage

Garbage has useful and non-useful components.

Useful garbage components are those that can be decayed easily. The process of decaying is

known as composting. Useful garbage components are fruit and vegetable waste, plant and

animal waste, tea leaves, coffee grounds and paper. These useful components of garbage are

converted into manure in the soil.

Non-useful garbage components include polythene bags, plastics, glass and aluminium foils.

These take longer to decay. Decaying of these non-useful components is known as

decomposition. When non-useful components decay, they release harmful gases that damage the

environment. To avoid the adverse impact, these garbage items are sent for recycling.

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For example, when leaves burn, they release harmful gases and causes air pollution. Moreover,

they lead to asthma and lung diseases. That is why leaves should be buried so as to convert them

into manure.

Vermicomposting

The process of preparing compost with the help of red worms is called vermicomposting. The

red worm is a type of earthworm that lives in the soil rich in organic matter, which is a

combination of nitrogen-rich and carbon-rich material with plenty of moisture and microbes.

Method of Vermicompositing

A vermicomposting pit is made with a wooden box or big cement rings.

A mesh is spread at the bottom of the pit.

Vegetable waste, fruit waste, waste paper which is not shiny or coated with plastic, is spread over

the mesh.

Water is sprinkled to create moisture so that the red worms can live.

A vermicomposting pit takes nearly two to four weeks to completely convert waste into manure.

Waste material that is rich in oils, salt, meat and vinegar stops the growth of red worms. These

red worms have a special structure called gizzards with which they grind food material. A red

worm eats food equal to its weight every day. Red worms do not survive in too hot or too cold

conditions.

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Recycling Paper and Plastics

It is important to reuse things than discarding

them as waste.

It is important to reuse things than discarding them as waste. Many nice articles can be made out

of waste.

Industries use recycled or waste paper to regenerate paper. Paper that is suitable for recycling is

called "scrap paper". You can recycle old newspapers, magazines, notebooks and used

envelopes, but not waxed paper, oil-soaked paper, paper contaminated with food, carbon paper,

thermal fax paper, plastic laminated paper, stickers, and sanitary products or tissues.

Steps involved in recycling paper

Tear paper into small pieces.

Soak these pieces in water for a day.

Make a thick paste and spread it on a net or sieve.

Let water drain off completely.

Use an old cloth or newspaper to remove the extra water from the paste and dry it.

Use this paste to get beautiful patterns.

Disadvantages of using of polythene bags

We use many plastic items such as tooth brush, combs, containers, bottles, shoes, toys, wires,

frames and bags every day. Certain parts of vehicles like cars and buses, and electronic goods like

radios, televisions and refrigerators, are all made of plastic. All these are useful to us in many

ways, but using plastic is very harmful in terms of health and as well as the environment.

Plastics are not suitable for storing cooked food because they emit harmful chemicals when they

are exposed to high temperatures. Using plastics causes health problems such as heart disease,

VI I.I.T. Foundation, N.T.S.E. & Science Olympiad Biology Chapter Notes Page 34

diabetes and reproductive dysfunction. Harmful gases are emitted from burning plastics, which

cause cancer and they kill living beings.

That is why plastics should be disposed in the right way.

Plastics that do not contain the chemical, BPA, are usually licensed for storing food items.

Plastics thrown casually get into drains and sewages, often blocking the way and causing water-

logging. A major cause of the floods in Mumbai, India, in August 2005 was the choking of the

drainage system by plastic waste. So polythene bags should not be used for garbage disposal.

Measures taken to prevent from the dangerous effects of plastics:

Adopt healthy practices such as:

Reduce, reuse and recycle plastics.

Carry jute or cloth bags for shopping

Do not store food items in plastic bags.

Do not burn plastic items.

Recycle plastics so that new plastic items can be made.

Waste that does not decompose should be put in blue dustbins, while waste that

decomposes easily should be put in green dustbins.

Vermicomposting

Conversion of the waste generated in the kitchen into organic matter with the combined action of

earthworms and micro-organisms is called vermicomposting. The organic matter so formed is

used as manure for plants.