Science project

•The act of breathing air in and out is called respiration.
•Respiration is essential for survival of living organisms. It releases energy from the food.
•The oxygen we inhale is used to breakdown glucose into carbon dioxide and water. Energy is
released in the process.
RESPIRATION
The breakdown of glucose occurs in the cells of an organism (cellular respiration).
TYPE OF CELLULAR RESPIRATION
•If the food is broken down with the use of oxygen, it is called aerobic respiration.
•If the breakdown occurs without the use of oxygen, the respiration is calledGGGG
anaerobic respiration.
CELLULAR RESPIRATION

• Breathing is a part of the process of respiration during which an organism takes in the oxygen-
rich air and gives out air rich in carbon dioxide with the help of respiratory organs.
• It involves two steps:
a. Inhalation: The taking in of air, i.e., rich in oxygen, into the body is called inhalation.
b. Exhalation: Giving out of air, i.e., rich in carbon dioxide is known as exhalation. Ghd
• During inhalation, our lungs expand and then come back to the original state as the air moves
out during exhalation.
• Increased physical activity enhances the rate of breathing.
BREATHING

Mechanism of breathing in human beings

The respiratory organs and the process of breathing of other organism
•In animals like cow, buffalo, dog and cat the respiratory organs and the process of breathing
are similar to those in humans.
•In earthworm, the exchange of gases occurs through the moist skin.
•In fishes it takes place through gills and In insects through the tracheae.
Tracheal systemBreathing organs in fish

The respiratory organs and the process of breathing of other organism
In a plant the roots take in air present in the soil.
Leaves have tiny pores called stomata through which they exchange gases.
The breakdown of glucose in the plant cells is similar to that in other living beings.
Roots absorb air from the soil

TRANSPORTATION IN ANIMALS
AND PLANT

HEART AND BLOOD VESSELS
All organisms need food, water and oxygen for survival. They need
to transport all these to various parts of their body. Further, animals
need to transport wastes to parts from where they can be removed.
Heart and blood vessels function to transport substances and
together form the circulatory system.

BLOOD
•In most animals the blood that circulates in the body distributes hfood and oxygen to
different cells of the body. It also carries gwaste products to different parts of the body
for excretion.
•Blood consists of plasma, RBC, WBC and platelets. Blood is red jdue to the presence of a
red pigment, haemoglobin.
•Blood is the fluid which flows in blood vessels.

HUMAN HEART
•The human heart beats about 70–80 gtimes per
minute in an adult person. This is called heart rate.
•Arteries carry blood from the heart
gto all parts of the body.
•The heart is located in the chest cavity with its
lower tip slightly tilted towards the left.
•Veins carry blood from all parts of
fthe body back to the heart.

HUMAN EXCRETORY SYSTEM
Removal of waste products from the body
is called excretion.
Excretory system of humans consists of
two kidneys, two ureters, a urinary bladder,
and urethra.

TRANSPORTATION IN PLANTS
•Water and mineral nutrients are absorbed by roots from the soil.
•Nutrients are transported along with water to the entire plant via the vascular tissue called xylem.
•The vascular tissue for the transport of food to the various parts of the plant is phloem.
•A lot of water is lost by plants in the form of vapour through stomata during transpiration.
•Transpiration generates a force which pulls up water absorbed by the roots from the soil, to reach
the stem and leaves.

• The production of new individuals from their parents is known as reproduction.
RERODUCTION
• All organisms multiply or reproduce their own kind.
Reproduction in
Plants
ASEXUAL
REPRODUCTION
Vegetative
propagationBudding
Spore formationFragmentation
SEXUAL
REPRODUCTION

1) Reproduction :-
Reproduction :- is the production of new individuals
from their parents.
The vegetative parts of the plant are the roots, stem and
leaves.
The reproductive parts of the plant are the flowers.
In plants there are two main types of reproduction. They
are asexual reproduction and sexual reproduction.
i) Asexual reproduction :-
In asexual reproduction new plants without the help of
seeds.
ii) Sexual reproduction :-
In sexual reproduction new plants are produced from
seeds.

2) Asexual reproduction :-
In plants there are different types of asexual reproduction. They are
vegetative propagation, budding, fragmentation, spore formation etc.
i) Vegetative propagation :-
In this method, new plants are produced from the vegetative parts like
the root, stem or leaves.
Eg :- If the stem cutting of a rose plant or money plant is planted in the soil
we can get a new plant.
Potato has small buds called eyes. If a part of the potato with an eye is
cut and planted in the soil we can get a new plant.
If a part of ginger is planted in the soil we can get a new plant.
Bryophyllum has buds in the leaf. If a part of the leaf with bud is
planted in the soil we can get a new plant.
If a part of a cactus plant is planted in the soil we can get a new plant

Stem cutting of rose Money plant Potato plants sprouting from eyes
Ginger with new plants
Cactus
Bryophyllum leaf
with new plants

ii) Budding :- Eg :- Yeast
In this method a small projection called bud is formed on the yeast
cell. The bud grows and becomes a new yeast cell. The new yeast cell
also grows and produces more yeast cells.
Bud
New
cell
Budding in yeast cells
Yeast cell

iii) Fragmentation :- Eg :- Spirogyra
In this method the plant breaks up into two or more fragments and each
fragment grow into new plants.

iv) Spore formation :- Eg :- Fungus, Fern etc.
In this method the fungus produces spores. The spores
germinate and produces new plants.
Spore formation in fungus

3) Sexual reproduction :-
Flowers are the reproductive parts of the plant. Stamen is the male reproductive part and pistil
is the female reproductive part.
Flowers which have only the stamen or only the pistil are called unisexual flowers. Eg :- Maize,
Papaya, Cucumber etc.
Flowers which have both the stamen and pistil are called bisexual flowers. Eg :- Rose, Mustard,
Petunia etc.
The stamen has a filament and anther. The anther contains pollen grains which contain the male
gametes.
The pistil has stigma, style and ovary. The ovary contains ovules which contain the female
gamete or egg.
In sexual reproduction the male and female gamete fuse together to form a zygote.

Reproductive parts of a flower

a) Pollination :-
The transfer of pollen grains from the anther to the stigma of a flower is called
pollination.
Pollen grains are transferred by wind, water or insects.
If pollen grains lands on the stigma of the same flower, it is called self pollination.
If pollen grains of one flower lands on the stigma of another flower it is called cross
pollination.

b) Fertilisation :-
The process of fusion of the male and female gametes to form a zygote is called
fertilisation.
After fertilisation the zygote develops into an embryo. The ovule then develops into the
seed and the ovary develops into the fruit.

4) Seed dispersal :-
The carrying away of seeds from one place to another is called dispersal of seeds.
Seeds are dispersed by wind, water and animals.
Seeds dispersed by wind are light, have wings or hairs so that they are easily blown
away by wind. Eg :- drumstick. maple, sunflower, aak etc.
Seeds dispersed by water have spongy or fibrous outer cover so that they can float on
water. Eg :- coconut
Seeds dispersed by animals have spines with hooks so that they can attach to the
bodies of animals. Eg :- xanthium

1) Motion :-
Motion :- is the change in position of an object with time.
There are different types of motions. They are :-
i) Motion along a straight line (Rectilinear motion) Eg :-
Motion of a car on a straight road.
ii) Periodic motion. Eg :- Motion of a pendulum.
iii) Circular motion. Eg :- Motion of the earth around the sun.
Motion along a straight line Periodic motion Circular motion

2) Speed :-
Speed :- The distance covered by an object in a unit time is called the speed of
the object.
Eg :- If a car covers a distance of 100 kilometres in one hour and a bus covers a
distance of 50 kilometres in one hour, then the speed of the car is more than the
speed of the bus.
Since the speed of most objects are not constant, the speed is the average speed.
Total distance covered
Speed = --------------------------------
Time taken
Uniform motion :- If the speed of an object is constant, it is in uniform motion.
Non uniform motion :- If the speed of an object keeps changing, it is in non uniform
motion.

3) Measurement of time :-
Time is measured by using clocks or watches. Clocks and watches make use
of periodic motion.
Digital clocks

4) Simple pendulum :-
A simple pendulum has a small metallic bob suspended from a stand by a
thread.
If the bob is taken to one side and released, it moves to and fro. The to
and fro motion of the simple pendulum is called periodic motion or
oscillatory motion.
Thread
Bob A O
B

Oscillation :-
When the bob moves from the mean position O to A and to B and back to O,
it is called one oscillation.
When the bob moves from one extreme position A to the other extreme
position B and back to A, it is called one oscillation.
Time period :-
The time taken by the pendulum to complete one oscillation is called its time
period.
A
O B
Mean position
Extreme positionExtreme position

5) Units of time and speed :-
a) The basic unit of time is second (s).
The larger units of time are minutes (min), hours (h) etc.
b) The basic unit of speed is metre per second (m/s).
A larger unit of speed is kilometre per hour (km/h).
6) Ancient time measuring devices :-
Some ancient time measuring devices were Sun dials, Water clocks
and Sand clocks.

SUN DIAL WATER CLOCK
SAND CLOCK

7) Measuring speed :-
The speed of an object can be measured if we know the distance
covered by the object and the time taken.
Eg :- If a car covers a distance of 100 kilometres in two hours, then the
speed of the car is :-
Distance covered – 100 km
Time taken – 2 hr
Distance 100
Speed = ------------- = ----- = 50 km/h
Time 2
If we know the speed of the car and the time, we can find the distance
covered by it.
Distance = Speed x Time
= 50 x 2 = 100 km
If we know distance covered by the car and the speed, we can find the
time taken.
Distance 100
Time = ------------- = ----- = 2 hr
Speed 50

8a) Speedometer :-
Speedometer is a device which measures the speed of vehicles
in km/h.
b) Odometer :-
Odometer is a device which measures the distance covered by a
vehicle.
Speedometer Speedometer and Odometer

9) Distance – Time graph :-
The distance distance travelled by a car and the time taken is shown in the table below.
If the distance – time
graph is a straight
line, then the object
is moving with constant
speed. If the speed
keeps changing, the
graph can be of any
shape.
Sl.No. Time Distance
1 0 0
2 1 min 1 km
3 1 min 2 km
4 3 min 3 km
5 4 min 4 km
6 5 min 5 km

ELECTRIC CURRENT AND ITS
EFFECT

Electric current and its effects
1) Symbols of electric components :-
Electric component Symbol
i) Electric cell
ii) Electric bulb
iii) Switch in
OFF position
iv) Switch in
ON position
v) Battery
vi) Wire

Electric cell :- has a positive terminal and a negative terminal.
The symbol of an electric cell has a longer line and a shorter
line. The longer line is the positive terminal and the shorter line
is the negative terminal.
Battery :- A battery is a combination of two or more cells. In a
battery the positive terminal of one cell is connected to the
negative terminal of another cell. Devices like torches,
transistors, toys, TV remote controls use batteries.
Connecting cells together Cell holder

A simple electric circuit can be made by using a cell, electric
bulb, switch and wires.
The bulb glows only when the switch is in the ON position
and the circuit is closed.
Closed electric circuit
Open electric circuit
An electric circuit
2) A simple electric circuit :-

3) Heating effect of electric current :-
When electric current flows through a wire, the wire gets
heated. This is called the heating effect of electric current.
Activity :-
Make an electric circuit as shown in the figure. Take a 10 cm
long nichrome wire and tie it between the two nails. Switch on
the current. After a few seconds touch the wire. The wire feels
hot. Then switch off the current. After a few seconds touch the
wire again. It does not feel hot. This shows that when electric
current flows through a wire, it gets heated.

4) Uses of heating effects of electric current :-
The heating effect of electric current is used in electrical appliances
like electric heater, electric iron, electric room heater, immersion
heater, electric kettle, hair dryer etc.
All these appliances have a coil of wire called an element. When
electric current flows through the element it becomes hot and gives
out heat.
The amount of heat produced in a wire depends upon its material,
length and thickness.
Electric heater
Electric room heater Electric iron Electric kettle

5) Electric fuse :-
Electric fuse is a safety device used in electrical circuits which
protects the electrical circuits and appliances and prevents fires.
Electrical fuse is used in all electrical circuits in buildings.
Electric fuse has a wire which melts quickly and break when
large electric current flows through it.
Fuse used in buildings Fuses used in electrical
appliances

6) Magnetic effect of electric current :-
When electric current flows through a wire, it behaves like a
magnet. This is called magnetic effect of electric current.
Activity :-
Take the cardboard tray from a match box. Wind an electric
wire a few times around the cardboard tray. Place a small
compass needle inside it. Connect the free ends of the wire to an
electric cell through a switch. When the switch is ON, the
compass needle deflects. When the switch is OFF, the compass
needle comes back to its original position. This shows that when
electric current flows through a wire, it behaves like a magnet.

7) Electromagnet :-
When electric current is passed through a coil of insulated wire
wound around a piece of iron, it becomes a magnet. Such a
magnet is called an electromagnet.
Activity :- Wind a piece of insulated wire around an iron nail in
the form of a coil. Connect the free ends of the wire to an electric
cell through a switch. Place some pins near the nail. When
electric current is passed, the iron nail becomes a magnet and
attracts the pins. When electric current is switched off, the nail
loses its magnetism.

8) Electric bell :-
The electric bell has a coil of wire wound around a piece of iron which acts
like an electromagnet. An iron strip with a hammer is kept close to the
electromagnet. There is a contact screw near the iron strip. When the iron strip
is in contact with the screw, current flows through the coil and becomes an
electromagnet. It pulls the iron strip and the hammer at the end of the strip
strikes the gong of the bell and produces sound. When the electromagnet
pulls the iron strip, it also breaks the circuit and the iron strip comes back to
the original position and the process repeats and the bell rings.

Light
1) Light travels along a straight line :-
Activity :-
Light a candle and fix it on a table. Take a piece of straight pipe or a
rubber tube. Look at the candle through the pipe. You can see the candle
flame. If the pipe is bent, you cannot see the candle flame. This shows that
light travels along a straight line.

Light
2) Reflection of light :-
When light falls on a mirror, the direction of light changes. This change
in the direction of light by a mirror is called reflection of light.
Activity :- Take a torch and cover its glass with a chart paper. Having a small hole.
Spread a chart paper on a wooden board. Keep a plane mirror vertically on it. Direct a
beam of light at an angle to the mirror. The direction of light changes. If the torch is
moved slightly to either side, the direction of light also changes.

Light
3) Image formed by a plane mirror :-
i) The image is erect.
ii) The image is same size as the object.
iii) The image is at the same distance from the mirror as the object is
in front of it.
iv) The image is virtual (cannot be obtained on a screen).
v) In the image the right side appears left and the left side appears
right.

Light
4a) Spherical mirrors :-
Spherical mirrors are curved mirrors.
If the reflecting is inside, the spherical mirror is a concave
mirror.
If the reflecting surface is outside, the spherical mirror is a
convex mirror.
Eg :- A stainless steel spoon also act like a mirror. The inner
side acts like a concave mirror and the outer side acts like a
convex mirror
Concave Convex

Light
b) Image formed by Concave mirror :-
i) The image formed by a concave mirror may be smaller or larger than
the object.
ii) The image may also be real (can be obtained on a screen) or virtual
(cannot be obtained on a screen).
iii) The image may inverted or erect.
Activity :- Fix a concave mirror on a screen. Light a candle and keep it at a
distance of 50 cm from the mirror. Try to obtain the image of the candle flame
on a screen by moving the screen. Observe the image. Then move the
candle closer to the mirror at different distances and observe the images.
Distance of object from the mirror Smaller / Larger than the object Inverted / Erect Real / Virtual
50 cm
40 cm
30 cm
20 cm
10 cm
5 cm

Light
c) Uses of Concave mirrors :-
Concave mirrors are used as reflectors in torches,
headlights of cars, scooters etc.
Concave mirrors are used by dentists to see enlarged
images of teeth.
Concave mirrors are used by doctors for examining eyes,
ears, nose and throat.

Light
d) Image formed by Convex mirror :-
i) The image formed by a convex mirror is virtual (cannot
be obtained on a screen).
ii) The image is smaller in size than the object.
e) Uses of Convex mirror :-
Convex mirrors are used as side mirrors in cars, scooters etc.
Convex mirror has a wider view to help drivers to see the
traffic behind them.

Light
5a) Lenses :-
Lenses are of two main types. They are Convex lenses and concave
lenses.
i) Convex lens is thick in the middle and thin at the
edges. A convex lens bends light inwards. So it is called
converging lens.
ii) Concave lens is thin in the middle and thick at the edges.
A concave lens bends light outwards. So it is called
diverging lens.

Light
b) Image formed by Convex lens :-
i) The image formed by a convex may be smaller or larger
than the object.
ii) The image may also be real (can be obtained on a screen)
or virtual (cannot be obtained on a screen).
iii) The image may inverted or erect.
c) Image formed by Concave lens :-
i) The image formed by a convex mirror is virtual (cannot
be obtained on a screen).
ii) The image is smaller in size than the object.
d) Uses of lenses :-
Lenses are used in spectacles, microscopes, telescopes,
cameras etc.

Light
6a) Sunlight – White or coloured ?
A rainbow is usually seen in the sky after a rain when the sun
is low in the sky. A rainbow has seven colours. They are – red,
orange, yellow, green, blue, indigo and violet.
Activity :-
Take a glass prism and allow a narrow beam of sunlight to fall
on one side of the prism. Keep a screen on the other side of the
prism. We can see that seven rainbow colours on the screen.
This shows that sunlight or white light is a mixture of seven
colours.

Light
b) Mixing the rainbow colours produces white light :-
If the seven rainbow colours are mixed together, it produces
white light.
Activity :- Take a circular cardboard and divide it into seven
segments. Paint the seven rainbow colours on it. Make a small
hole in the centre of the disc. Fix the disc on the tip of a refill of
a ball pen. When the disc is rotated fast, the colours get mixed
and appears white in colour. This disc is known as Newton’s
colour disc.

Water: A Precious Resource
1) World water day :-
The year 2003 was observed as the INTERNATIONAL YEAR OF
FRESHWATER to make people aware of this dwindling natural resource.
22 MARCH is celebrated as the WORLD WATER DAY.

2) Water on the earth’s surface :-
About 71 % of the earth’s surface is covered with water. Water is present
in the oceans, seas, rivers, lakes, ice caps, as ground water and in the
atmosphere.
Most of this water is not fit for human consumption. The water that is fit for
human use is freshwater.

3) Water cycle :-
The water from the oceans and surface of the earth evaporates and rises up in the air. It cools
and condenses to form clouds and then falls back to the earth as rain, snow or hail. This
circulation of water between the oceans and land is called water cycle.
In the water cycle, water is found in three different forms as solid, liquid and gas.
The solid forms of water are ice, and snow is found as ice caps at the poles and snow covered
mountains and glaciers.
The liquid form of water is found in oceans, lakes, rivers and as underground water.
The gaseous form of water is found as water vapour in the air around us.

Water cycle

4) Groundwater :-
Water is present underground as groundwater. The upper layer of the groundwater is called
the water table. The water table may be at a depth of one metre or at a depth of several metres
below the ground.
The water from rain, rivers, lakes and ponds seeps through the soil and fills the space below
the ground. The process of seeping of water through the soil is called infiltration.
At some places groundwater is stored between layers of hard rock. This is called aquifier.
Water from aquifiers is pumped and taken out through hand pumps and tube wells.

5) Depletion of water table :-
If we draw more water from the ground than the amount of
water which seeps into the ground, then the water table goes
down and gets depleted.
Water table gets depleted due to :-
i) Increase in population
ii) Industrial activities
iii) Agricultural activities
iv) Decrease in rainfall
v) Deforestation

6) Distribution of water :-
- The distribution of water is not the same at all places on
the earth.
- Some places have more rain and are rich in water and
some places like deserts have less rainfall.
- Excess rain cause floods and lack of rain causes
drought.
Drought Flood

7) Water management :-
Water management is preventing wastage of water, using water carefully and recharging
ground water.
Water management can be done by :-
i) Repairing leaking pipes and taps.
ii) Not wasting water during brushing teeth, shaving, bathing, washing
clothes and during other activities.
iii) Rainwater harvesting.
iv) By drip irrigation of plants.
Drip irrigation :- is a method of watering plants using narrow pipes
through which water drips into the base of the plants.

Rainwater harvesting

Forests : Our lifeline
1) Forest :-
Forest is a natural habitat for many different kinds of plants
and animals. Forests provide food and shelter for animals.
Some common animals found in a forest are :- lion, tiger,
elephant, monkey, deer, zebra, jackal, bison, boar, snake,
porcupine, crocodile etc.

Some common types of plants found in forests
are :- trees like teak, bamboo, fig, saal, sesham,
semal, neem, palash, khair, amla, kachnar etc.
Forests also have several kinds of shrubs, herbs
and grasses, climbers, creepers etc.
TEAK BAMBOO FIG SHEESHAM
SAL NEEM AMLA KACNAR

2) Products we get from forests :-
We get several useful products from forests like wood, spices, gum, oils, honey, sealing wax,
catechu, fodder for animals, medicinal plants etc.

3) Characteristics of trees in forests :-
The branchy part of a tree above the stem is called the crown of the tree.
The crown of trees have different shapes.
.
Some crown shapes of trees
Trees have different heights, crowns,
shapes of leaves, flowers and fruits.
The branches of tall trees look like a roof over the other
plants in the forest. This is called a canopy.

4) Interdependence of components of forest :-
Forest has different types of plants and animals. They are
autotrophs, heterotrophs, saprotrophs and decomposers.
Autotrophs:- are green plants which prepare food by
photosynthesis.
Heterotrophs:- are animals which get their food directly or
indirectly from plants.
Saprotrophs:- are animals which feed on dead animals.
Decomposers:- are micro organisms which decompose dead
plants and animals into humus.
Food chain:- Organisms which feed on plants are eaten by
other organisms and so on to form food chains.
Eg : Grass Insects Frog Snake Eagle
There are many food chains in the forest. All food chains are linked together.
If any food chain is disturbed, it affects other food chains.
Every component of forest depends on one another. If we remove one
component like trees, all the other components are affected.

5) Balance of oxygen and carbon dioxide in the
atmosphere :-
During respiration plants and animals take in oxygen and release carbon dioxde.
During photosynthesis plantstake in carbon dioxide and release oxygen. So plants
help to maintain the oxygen and carbon dioxide balance in the atmosphere.
This is why forests are called green lungs.

6) Importance of forests :-
i) Forest is a natural habitat for a large number of plants
and animals.
ii) Forest help in maintaining the oxygen and carbon
dioxide balance in the atmosphere.
iii) Forests help in bringing good rainfall.
iv) Forest help to protect soil from erosion.
v) Forest absorb rainwater and helps to maintain water
table.
vi) We get medicinal plants, timber and many other useful
products from forests.
vii) Many people live in forests and forest provide them
with food, water, shelter and medicines.

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