New Way
7
GURUKUL PUBLICATIONS (P) LTD.
CHAPTER 1
Test Yourself, Page No. 10
1. Yes.
2. Because they can make their food on their own with the help of carbon dioxide, water,
chlorophyll and sunlight.
3.
6 CO2 + 6 H2O
Sunlight
C6H12 O6 + 6O2
Carbon
Oxygen
Glucose
Water
Chlorophyll
di-oxide.
4. Small pores present in the leaves.
Test Yourself, Page No. 12
1. Organisms that depend on other organisms for food.
2. Saprophytes obtain their food from dead and decaying matter of plants or
animals but parasites live either in the body or on the body of the other living organism
to obtain food.
3. Symbiosis is a type of relationship between two organisms in which both the partners are
equally benefitted e.g. Lichen is a close association of algae and fungi. Algae prepares
food for fungi and fungi provides water, minerals and shelter to algae.
4. Insectivorous plants are those plants that feed on insects.
Formative Assessment, Page No. 12
A. 1. (c) 2. (b) 3. (d) 4. (c) 5. (d).
B. 1. Nutrition 2. Chemical 3. Glucose 4. Others, nutrition 5. Parasites.
C. 1. (e) 2. (d) 3. (f) 4. (a) 5. (b) 6. (c).
D. 1. F 2. T 3. T 4. T 5. T.
E. 1. Nutrition – The process of taking and utilizing the food is termed as nutrition.
2. Cuscuta, fungi, bacteria.
3. Autotrophic Nutrition – Type of nutrition in which organisms like green plants can
prepare their own food making use of raw materials.
4. Photo means light.
5. Type of nutrition in which an organism depends on insects for food.
Summative Assessment, Page No. 14
A. 1. The different components of food are carbohydrates, fats, proteins,
vitamins, minerals and water.
2. Different types of heterotrophic nutrition are
(i) Saprophytic nutrition.
(ii) Parasitic nutrition.
(iii) Symbiotic nutrition.
(iv) Insectivorous nutrition.
3. Differentiate between autotrophic and heterotrophic nutrition
Autotrophic Nutrition
Type of nutrition in which
organisms can prepare their own
food making use of raw materials.
(b) Example green plants.
(a)
4.
(a)
Heterotrophic Nutrition
Type of nutrition an in which
organisms depend on other
organisms for food.
(b) Example Parasites, cuscuta,
saprohytic mushroom etc.
Photosynthesis
'Photo' means 'light' and 'synthesis' means to 'combine'.
Therefore the process of making food by green plants in the presence of
sunlight is called photosynthesis.
Process of Photosynthesis
(i) The Plants contain green pigments in their leaves, called chlorophyll. These green
pigments trap sunlight during the day and convert light energy into chemical
energy. Thus, Sun is the ultimate source of energy for all living organisms.
(ii) Water absorbed by the roots is sent to different parts of the plants. During the
process of photosynthesis water molecules present in the ells break up and
oxygen present in water is set free.
(iii) The hydrogen from the water molecules combines with
carbondioxide (CO2) from the environment to form glucose, asimple sugar.
Plants take in CO2 through small pores present in their leaves called
stomata.
(iv) The chemical energy is trapped within the glucose molecules.
5. Importance of Photosynthesis
(i) Photosynthesis is the only process through which solar energy, which is the only
source of energy, is converted into chemical energy by the green plants in the
form of food.
(ii) During the process of photosynthesis plants take in CO2 and release O2. In this
way plants maintain the ratio of these two gases in the atmosphere.
(iii) Without it plants and animals will not survive.
6. Saprophytic Nutrition
Parasitic Nutrition
Some non-green plants live on dead Some organisms depend on other living
bodies or organic remains of plants and organisms to obtain food. This type of
nutrition is called parasitic nutrition.
animals, rotten food products etc.
7.
Symbiotic Nutrition:
Symbiotic nutrition is a mode of nutrition in which two different organisms depend
on each other for shelter and nourishment, and both are benefitted. These organisms
are called symbiotic organisms. Lichen is the most common example of symbiotic
nutrition.
Insectivorous Nutrition
Insectivorous is made up of two words insects and vorare-to eat. Insectivorous
organisms supplement their nutritional requirement by trapping and digesting insects
and other animals to get required proteins. Such plants are called carnivorous or
insectivorous plants. This type of nutrition is called insectivorous nutrition. The
pitcher plants, the sundew, Venus, fly trap and the bladder wort are examples.
8. The name of four heterotrophs are as (i) Saprophytic Nutrition (ii) Parasitic Nutrition (iii) Symbiosis or Symbiotic
Nutrition (iv) Insectivorous Nutrition.
B. HOTS
1. No, leguminous plants add nitrogen to the soil by the process of nitrogen fixation.
2. They cannot prepare their food but trap and digest insects to get required proteins.
3. It has green leaves and can produce its own food but gets water and minerals from
the host plants.
4. We only lcook the food. Autotrophs prepare the food using raw materials.
5. Photosynthesis does not take place due to the absence of light.
CHAPTER 2
Test Yourself Page No. 19
1. Ingestion – The process of taking food into the body is called ingestion.
2. The animals e.g. the protozoans-Euglena, Volvox which contain chlorophyll have
retained auto atrophic mode of nutrition.
3. Herbivores – Animals that depend on plants for food.
Omnivores – Animals that depend on plants and animals both for the food.
4. Mostly in unicellular organisms.
5. In food vacuole.
Test Yourself, Page No. 21
1. (a) Incisors : Front four teeth, flat in shape and help in biting and cutting the
food.
(b) Canines : Sharp and pointed teeth present just besides the incisors in both the
jaws these are four in number and help us in
tearing the food.
(c) Premolar and molars these are very strong broad and flat surfaced teeth, present on
the either side of the canines. These are used for crushing and grinding the food.
2.
3.
Amylase is an enzyme present in saliva.
The lining of the stomach secretes digestive juices which contain mucus, hydrochloric
acid and digestive enzymes.
Peristaltic movement in the stomach helps in mixing of food with gastric juices and turns
it into a watery paste called chyme. Food remains in the stomach for 2-4 hours, there
most of the food is digested.
4. Inner membrane of small intestine has millions of minute finger like projections called
Villi. These increase the surface are a for absorption.
Test Yourself, Page No. 22
1.
Animals that feed on grass and can digest cellulose.
2.
Rumen, reticulum, omasum and abomasum.
3.
They chew the half digested food called cud that reaches the mouth from the reticulum.
4.
In this chamber food mixes up with various enzymes and then passes into small
intestine for digestion.
Formative Assessment, Page No. 23
A. 1.
(c) 2. (d) 3. (a) 4. (a) 5. (b).
B. 1.
Carnivores 2. Milk teeth 3. Tongue 4. Chyme 5. Pancreatic juice
6.
Abomasum.
C. Difference between Carnivores and Omnivores.
1.
Carnivores
Omnivores
1.Organisms
who eat plants as well as flesh.
1. Organisms who feed on flesh.
For example lion, tiger etc.
2.
3.
D.
E.
F.
1.
1.
1.
2.
3.
For example man.
Premolars and molars are very strong teeth with broad and flat surface and are on either
side of canines.
Difference Milk teeth and Permanent teeth.
Milk teeth
Permanent teeth
1. These are present in children.
1. These are present in adolescents and adults.
2. These are temporary.
2. These are permanent.
(f) 2. (a) 3. (e) 4. (b) 5. (d) 6. (c).
T 2. F 3. F 4. T 5. T.
Feeding on solid organic matter.
Distribution of absorbed nutrients to different parts of the body.
It has small taste buds on its surface to taste the food. Besides this the main functions of
the tongue are.
v It helps in mixing saliva with food.
v It helps in swallowing the food.
v It helps us to speak.
4.
Hollow muscular tube that pushes the food down into the stomach.
5.
At the meeting point of stomach and small intestine.
6.
Pathway followed for the digestion of food.
Summative Assessment, Page No. 24
A. 1.
Premolar and molars these are very strong broad and flat surfaced teeth, present on
the either side of the canines. These are used for crushing and grinding the food.
2. Stomach : Stomach is a T-shaped muscular bag which stores the food temporarily. It is
the widest part of the alimentary canal which receives the food and passes it to small
intestine. The lining of the stomach secretes digestive juices which contain mucus,
hydrochloric acid and digestive enzymes.
3.
It receives the partially digested food from the stomach and mixes its own digestive
juices with the food. In the small intestine bile juice from liver and pancreatic juice from
pancreas also mix with the food.
Bile juice makes the food alkaline and helps in the digestion of fats. Pancreatic juice
helps in the digestion of and Carbohydrates.
Intestinal juices complete the digestion of carbohydrates, fats and proteins.
4.
The undigested food moves from the small intestine to the large intestine. Large intestine
absorbs most of water and certain salts from the undigested food.
The ruminants have four chambers in their stomach. These are :
5.
(i) rumen
(ii) reticulum (iii) omasum
(iv) abomasum.
6. In rumen, bacteria and other microorganisms break down the food partially.
7.
Two pseudo podia join around the food and a vacuole is created. Amoeba engulfs the
food in the vacuole.
B. HOTS
1.
Nutrition and respiration.
2.
Drip has glucose which is directly absorbed by the body. It need not be digested.
3.
Our intestine doesn't have the design to digest cellulose.
4.
Salivary glands start to produce saliva when our favourite dish is brought in front of us.
CHAPTER 3
Test Yourself, Page No. 28
1. Cotton clothes allow air to pass through their holes and allow bodyheat to escape.
2. The art of breeding of silk worm for commercial use.
3. Bombyx mori is also called mulberry spinner because it feeds on the leaves of mulberry
tree.
4. The process of twisting the raw Silk into a strand.
5.
Uses of Silk
(i) Silk is generally used to make fancy dress materials especially
sarees, kurta and other dress materials.
(ii) Silk is also used in parachutes, bullet-proof vests, etc.
(iii) It is also used as non-absorable sutures in surgery.
Test Yourself, Page No. 29
1. Wool is obtained from different wool bearing animals like sheep, goats, yak, and
camels etc.
2. The wool produced by the merino sheep is the top quality wool.
3. Camel hair are used to make heavy durable textiles. It is also used in combination
with other types of wool to make coatings, blankets rugs and carpets of high quality.
4. Fleece is the thick coat of hair on a sheep's body.
5. Carding is the process of sending washed wool into carding machine which combs
the loose wool fibres into a sheet.
6.
Worsted cloth
Woollen cloth
1.
This type of woollen cloth is s p u n 1. This type of woolen cloth is
from combed wool fibres of same
spun from wool fibres of different
length.
length.
2.
I t h a s s m o o t h s u r f a c e w i t h 2. It is soft with fuzzy appearance.
minimum fuzziness.
Formative Assessment, Page No. 30
A. 1. (d) 2. (c) 3. (a) 4. (b) 5. (a).
B. 1. Fibres 2. Costly 3. China, Japan 4. 3 km 5. Worsted.
C. 1. T 2. F 3. T 4. T 5. T.
D. 1. Early man used leaves of plants, animals skin, bark of trees to cover his body parts.
2. Fibres are the raw materials which are used to make thread and then yarn.
3. Cotton, silk, wool are natural fibres.
4. Rayon, polyester, nylon are artificial fibres.
5. We obtain silk from cocoon of a moth.
6. Sheep, goat, yak and camel.
7. Worsted cloth is a type of woollen cloth spun from combed wool fibre of same
length.
8. Silk is obtained from the cocoons of wild moths or moths may be bred for the
purpose. Sericulture is widely used and practiced in China and Japan.
Summative Assessment, Page No. 31
A.
1.
(i)
Mulberry silk: It is produced by the worms of Bombyx mori.
Since these worms feed on mulberry leaves, so the silk produced by these
worms is called the mulberry silk. This silk is
the most common variety of silk. It is produced largely in the States of Andhra
Pradesh, Karnataka, Tamil Nadu, Jammu and Kashmir.
(ii) Tusser silk: It is obtained from the moths Antheraea mylitta and is produced in
Madhya Pradesh, Chhattisgarh, etc.
(iii) Muga silk: It is a beautiful expensive and coarse golden coloured silk
produced by the moth. Antheraea assamensis. The worms of this silk feed on
aromatic leaves of som and soalu plants. It is commonly produced in Assam.
(iv) Crepe silk: It is produced by twisting individual threads of raw silk and then
two or more threads are together twisted again.
(v) Tram silk: It is produced by twisting two or more threads in only one direction.
2. Variety of Wool
(i) The wool produced by the merino sheep is the top quality wool which account
for about one-third of world wool production.
(ii) The soft hair of Kashmir goats Pashmina is produced in the western Himalayas.
This is used for making Kashmiri shawls and other high quality knitted
garments.
(iii) Camel hair, which has long been used among the desert people to make heavy
durable textiles, is also used in mixtures with other types of wool to make
coatings, blankets, rugs and carpets of high quality.
3. Wool is obtained from the hair of same animals such as sheep, goat, yak and camel.
4. The production of wool fibre comprises various processes, these processes are
as follows:
(i) Rearing: Sheep are cultured or reared because of their wool. In India they are
reared in hills of Jammu and Kashmir, Himachal Pradesh, Uttrakhand, Sikkim
and Arunachal Pradesh.
(ii) Shearing: Wool is the long and soft hair of some animals. The thick coat of hair
on a sheep’s body is called ‘fleece’. This fleece is removed from its body by
using clippers. Removing animal hair from its body for commercial purpose is
called shearing. After the fleece is removed, it is examined for quality.
(iii) Scouring: This is the first and the most important process. In this process the
sheared wool is washed properly using detergent and chemicals to make it
clean, soft and germ free. This is known as scouring. Thereafter, it is made
smooth by oiling.
(iv) Sorting: It means separating fibres of different textures.
(v) Carding: It is the process in which washed wool is sent into a carding
machine. The carding machine combs the loose wool fibres into a sheet. Then
the sheet is twisted into ropes called ‘sliver’. The sliver is then stretched and
twisted into yarn.
(vi) Dyeing: Yarn is then dyed in different colours. Finally the yarn is wound to
form balls of wool. This wool is then used to make woollen garments. The
quality of wool is determined by the colour, fineness, the number of crimps per
unit length and the cleanliness of the fibre.
B. HOTS
1. The animal activisties oppose the procedure because when we obtaing silk from
cocoon, we boil it which kills the silk worm.
2. To make it clean soft and germ free.
3. Because threads of raw silk are too fine for textile manufacture.
4. They are dealing with filaments and inhaling the particles of filaments. Can cause
respiratory problems.
CHAPTER 4
Test Yourself, Page No. 37
1. Temperature is the degree of hotness or coldness of a body.
2.
3.
Celsius, Fahrenheit and Kelvin.
°C
°F – 32
K – 273
= 100
100 = 180
(i) Wash the thermometer properly with water or antiseptic solution and let it dry
before every use.
(ii) Never hold the thermometer at the bulb but hold it from its top end
and read the level of mercury.
(iii) If the level of mercury is above 35°C give few jerks to the thermometer to bring
down this level.
(iv) Bulb of the thermometer should be placed under the tongue or armpit carefully.
(v) After about one and a half minute take out thermometer and read the mercurylevel.
(vi) Don't speak during this time, till the thermometer is in the mouth.
5. Laboratory thermometer
A laboratory thermometer has a long thick walled capillary tube with a thin walled bulb
that contains mercury or alcohol at one end. The air in the portion of the tube above
mercury is removed by evacuation and the upper end of the tube is sealed.
6.
The thermometer is placed inside the mouth of the patient, the mercury thread expands
and moves up the narrow stem of the instrument. The temperature reading can be taken
after the thermometer has been removed from the patient's mouth.
Test Yourself, Page No. 39
1.
Heat gets transferred through
(i) Conduction
(ii) Convection
(iii) Radiation.
2.
Conduction is the process of transfer of heat from one body to another when they are
kept in close contact.
3.
No.
4.
Radiation is the process of transfer of heat without any medium.
5.
Conductors
Insulators
(i) Allow heat to pass
(i)
Do not allow heat
through them.
to pass through them.
e.g. metals.
e.g. paper, wood, plastics.
Formative Assessment, Page No. 39
A. 1. (c) 2. (d) 3. (b) 4. (b) 5. (c).
B. 1. Water vapour 2. Kinetic 3. Greater
4. Thermometer 5. William
Thompson 6. Radiation.
C. 1. T 2. T 3. T 4. T 5. T.
D. 1. Jacques Charles.
2. Temperature is the degree of hotness or coldness of an object.
3. The three scales of measurements of temperature are centigrade, Fahrenheit and
absolute.
4. Conduction, convection and radiation.
5. Radiation – The process of transfer of heat without any medium.
6. The inner wall of the bottle in a thermos flask has sliver coating to reduce the transfer of
heat from the inner bottle to outer one.
Summative Assessment, Page No. 41
A. 1. The Celsius Scale : In the Celsius scale, the temperature at which pure ice melts at
normal atmospheric pressure is taken to be zerodegree (°C) and the temperature at
which pure water boils (under normal atmospheric pressure) is taken to be 100°C. 0°C is
called lower standard point whereas 100°C is called upper standard point. The
distance between these two fixed points is divided in 100 equal
divisions. Each such division measures a temperature difference of 1°C (degree Celsius).
The Fahrenheit Scale : On the Fahrenheit scale named after Fahrenheit these fixed
points are defined as 32° F and 212° F respectively and the distance between them is
divided into 180 divisions.
2. The Clinical Thermometer
The Clinical Thermometer is also called the mercury thermometer or doctor's
4.
thermometer and mercury is used in it. This thermometer is specially designed to
measure human body temperature. It measures over a very limited range of 35°C –
43°C. Normal body temperature is 37° C (98.4° F).
Structure : The clinical thermometer is a glass tube of narrow bore with a wider bulb
like portion containing mercury at the bottom. The glass tube is marked with
temperatures in Celsius as well as Fahrenheit.
3. Conduction
Conduction is the process of transfer of heat from one body to another when they are
kept in close contact.
(i) Utensils for cooking are made up of metals like brass or aluminium as they are
good conductors of heat.
(ii) Electric wires are made up of copper or aluminium because of same reasons.
(iii) Handles of cooking utensils are made up of wood or plastic as they are bad
conductors of heat.
4. Convection
Convection takes place in liquids and gases. When portion of a liquid or gas gains heat,
its molecules increase their movement and tend to move farther apart.
Use of Convection
(i) In big buildings, central heating is based on the concept of convection currents.
(ii) The people living in coastal areas experience sea breeze during day time and land
breeze during night time due to the convection current flow.
5.
Conductors - Those substances that allow heat to pass through them. For example
metals.
Insulators - Do not allow heat to pass through them. For example paper, wood,
plastics.
6.
Thermos Flask
It is a bottle within a bottle but the two being united only around the top. The outer bottle
contains the inner bottle and temperature is to be kept constant. The loss of heat from the
material by conduction is greatly reduced.
Heat cannot be transferred from the inner bottle to the outer one by convection, since all
the air has been removed from the space between the walls of the two bottles. This
produces a vacuum, and a vacuum is not able to transfer heat by convection as air does.
B. HOTS
1. Kink in the thermometer prevents sudden, fall of mercury when thermometer is taken
out from the mouth.
2. 1oC rise is greater than1oF.
3. Clinical thermometer will break.
CHAPTER 5
Test Yourself, Page No. 48
1. Indicators are the substances which give different colours with acids and bases and help
us to identify the two.
Indicators
2.
Natural Indicators
Chemical Indicators
e.g. Turmeric Litmus.
e.g. Methyl orange.
3. Place petals of China rose in a beaker and add warm water into it. The coloured water
obtained is used as an indicator.
4. Ionisation is the process of splitting of ionic compounds into ions in aquoes or molten
state. For example
KOH
K+
+
OH–
Potassium
Potassium
Hydroxyl
hydroxide
ions
ions
5.
Indicator
Acids
Bases
Turmeric
no effect
red
China rose
magenta
green
Litmus
red
blue
Phenol
no colour change
pink
Test Yourself, Page No. 49
1. The reaction between an acid and a base is called neutralisation reaction.
2. When sodium hydroxide reacts with sulphuric acid, sodium sulphate and water is
formed and heat is released.
2NaOH + H2SO4
Na2SO4 + 2 H2O + Heat.
3. Neutralisation is an exothermic reaction.
4. Salts are the compounds produced along with water during the reaction between an
acid and a base.
5. Sodium chloride is the most common salt.
6. Role of neutralisation in
Indigestion- Anti acid tablets or gel contain magnesium hydroxide or aluminum
hydroxide which neutralise the acid produced in the stomach. In the field of agricultureSoil becomes acidic or alkaline due toexcessive use of fertilizers. To overcome this
problem farmers add calcium hydroxide (base) to reduce acidity and decaying organic
matter to reduce alkaline feature.
Formative Assessment, Page No. 50
A. 1. (a) 2. (c) 3. (b) 4. (d) 5. (b).
B. 1. Acidus 2. Biological 3. Phenolphathalein 4. Acetic 5. Alkalies.
C.
Indicators
Acids
Bases
Blue/ Red litmus
Red
Blue
Methyl orange
Red
Yellow
Phenolphathalein
No colour change
Pink
D. 1. Acidic, basic and neutral substances.
2. Because lemon contains citric acid.
3. Citric acid, tartaric acid and ascorbic acid are weak acids.
4. Naturally occuring acids are organic acids.
5. Three inorganic acids are nitric acids, sulphuric acid and phosphoric acids.
6. Indicators are substances which give different colours with acids and bases and help to
identify the two.
7. Substances that are alhaline in nature are called basic substances.
8. Water soluble bases form hydroxide while combining with water. These bases are also
called alkalies.
9. Neutralisation is a reaction between an acid and a base.
Summative Assessment, Page No. 51
A. 1. Difference between acids and bases.
Acids
i.
Acids are sour in taste.
ii. Acids are corrosive to touch.
iii. Acids turn blue litmus to red.
iv. Acids changeChina rose indicator to magenta.
v.
Acids have no effect on turmeric paper.
vi. Acids show no colour change with phenol phathalein.
vii. Acid change methyl orange to red.
viii. When dissolved in water release hydrogen (H+)ions.
Bases
i.
Bases are bitter in taste.
ii. Acids are soapy to touch.
iii Acids turn red litmus to blue.
iv Acids change China rose indicator to green.
v. Bases change turmeric paper red.
vi. Acids turn phenolphathalein pink.
vii. Acids change methyl orange to yellow.
viii. When dissolved in water release hydroxyl (OH–) ions.
2. Preparation of acids
Acids are produced when non-metallic oxides (residues obtained after
burning non-metals in the presence of oxygen) are dissolved in water.
(i) Carbon is a non-metal. When carbon reacts with oxygen,
carbon dioxide is formed which is acidic in nature.
C
+ O2
CO2
Carbon
Oxygen
Carbon dioxide
(non-metal)
(air)
(Acidic)
When carbon dioxide is dissolved in water, carbonic acid is
formed.
CO2 + H2O
H2CO3
carbon
water
carbonic
dioxide
acid
(ii) Sulphur is a non-metal. It reacts with oxygen to form sulphur
dioxide
S
+ O2
SO2
Sulphur
Oxygen
Sulphur
dioxide
(iii) When sulphur dioxide is dissolved in water, sulphurous acid is
formed.
SO2
+ H2O
H2SO3
Sulphur
Water
Sulphurous
dioxide
acid.
3. Same as in Question No. (i)
4.
B.
Physical Properties of Acids
(i)
Acids have sour taste.
(ii) Acids turn blue litmus red.
(iii) Acids turn methyl orange solution pink.
(iv) Acid does not show any effect when it is poured into an
acidic solution.
5. Hydrochloric Acid Uses – In cleaning metal wares and sanitary ware.– In
manufacturing glucose from starch.
Nitric Acid Uses – In making of explosives.
– In manufacturing fertilizers.
6. Indicators are used to find out whether a given substance is acidic or bases. Different
indicators give different colour with acids and bases for example.
Indicator
Acids
Bases
Litmus
Red
Blue
Methyl orange.
Red
Yellow
Phenolphathlein
No colour change
Pink
China rose
Magenta
Green
Turmeric paper
No effect
Red
HOTS
1. Acids are not stored in metal containers because acids react with metals.
2. When ant stings formic acid gets injected into the skin. Calamine being basic in nature
can neutralise the effect of formic acid.
3. Soap is alkaline in nature and turmeric gives red colour with alkalies.
4. Indigestion occurs due to acidity in the stomach. ENO is basic in nature can neutralise its
effects.
Practice Paper for Formative Assessment-I
Based on Chapter 1 to 5
A.
B.
C.
D.
E.
F.
1. Nutrition 2. Saliva 3. Bombyn Mori 4. William Thompson 5. KNO3
1. T 2. F 3. F 4. T 5. T.
1. Because fungi do not have chlorophyll.
2. Because it has to mix the food with gastric juices and turn into a watery
paste called chyme.
3.
4.
5.
1.
1.
2.
3.
These allow air to pass through their holes and allow body heat to.
To prevent falling of mercury.
Because baking soda is alkaline and neutralises the effect of formic acid injected by ant bite.
(c) 2. (c) 3. (b) 4. (d) 5. (a) 6. (a).
Nucleus, Vacuole, Food, Cell membrane.
Photosynthesis is the process of making food by green plants in the presence of sunlight. It is
important because
(a) It converts solar energy into chemical energy.
(b) It maintains the ratio of oxygen and carbon dioxide in the atmosphere.
(c) It helps plants and animals to survive.
Digestion of food is completed in the small intestine. The partially digested food received from the
stomach mixes with digestive juices from liver and pancreas. Bile juices from liver help in the
digestion Pancreatic juice from pancreas helps in the digestion of proteins and carbohydrates.
Refer Page No. 31 Question No. 4
4.
Heat is transferred by conduction convection and radiation, .Conduction - The
process of transfer of heat from one body to another when they are kept in close contact.
Convection takes place in liquids and gases.
Radiation -The process of transfer of heat without any medium.
5.
Properties of acids
(i)
Acids have sour taste.
(ii) Acids turn blue litmus red.
(iii) Acids turn methyl orange solution pink.
(iv) Acid does not show any effect when it is poured into an acidic solution.
(v) Some acids are soluble in water.
CHAPTER 6
Test Yourself, Page No. 59
1. Physical change is a change in which only physical properties of a substance change e.g.
colour, volume etc.
2. (i) During a chemical change, new substances with different properties are formed.
(ii) These are permanent and irreversible changes.
(iii) During a chemical change large amount of energy is absorbed or evolved specially
in the form of heat; light or sound.
3. Physical change different from Chemical change.
1.
2.
3.
Chemical change
Physical change
A change in which chemical 1. A change in which only physical
properties and chemical composition
properties of a substance change
of reacting substance change.
e.g. Colour, Volume, Shape,
One or more new substances are
Size, State etc.
formed.
2. No new substance is formed.
The reactant cannot be obtained by 3. The original substance i.e. reactant can
simple physical methods.
be obtained easily by simple physical
4. It is permanent and irreversible change.
5. For example:
(i) Digestion of food.
(ii) Germination of seed.
methods.
4. It is temporary and reversible change
5. For example:
(i) Burning of candle.
(ii) Glowing bulb.
4.
5.
Molecule is the smallest particle of a compound.
Formula
Components
Sugar
C12H22 O11
Carbon (12)
Hydrogen (22)
Oxygen (11)
Carbonic acid
H2 CO3
Hydrogen (2) Carbon (1)
Oxygen (3)
Test Yourself, Page No. 61
1.
A chemical reaction is chemical change in which a new compound is formed.
2.
When two or more elements or simpler substances react to form,a compound, such
reactions are called chemical reaction.
A+ B
AB
3.
Oxidation is a chemical reaction in which oxygen is added or hydrogen is removed from
the substance.
4.
Reduction is a chemical reaction in which oxygen is removed or hydrogen is added to
the substance.
5.
Conditions for rusting to take place are oxygen and water. Acidic gases
and salts increase the rate of rusting.
6.
4Na + O2
2Na2O
Formative Assessment, Page No. 62
A. 1.
(b) 2. (b) 3. (c) 4. (a) 5. Displacement.
B. 1.
Physical 2. Remains same 3.Decomposition 4. Properties
5.
Compound 6. Reactants.
C. 1.
Chemical change – A change which results in the formation of a new compounds with
different properties.
2.
Physical change – A change that involves change in physical properties only e.g.
shape, size, colour, state etc.
3.
Crystallisation – Process of obtaining a pure solid in geometrical shape or
in the form of crystals.
4.
Sulphuric acid- H2SO4?- Sugar - C12 H22 O11
5.
6.
2H2 + O2
2H2O
Chemical formula – Symbolic representation of elements or compounds according to
the presence of atoms in them.
Summative Assessment, Page No. 63
A. 1.
By applying Paint or grease or oil – It prevents moist air to come
in contact with the surface of iron and hence prevents rusting.
Galvanisation – Coating of an iron object with a thin layer of zinc is called
galvanisation.
Electroplating – Coating of corrosion resistant metal such as nickel, chromium etc. on
iron can prevent rusting especially in auto parts, bathroom fittings, showers etc.
Tinning – It is another method by which rusting can be prevented. Tin is a corrosion
resistant and non-toxic metal. It is used in cans for packaging ghee, oils, milk powder etc.
These cans are made of tinned iron sheet.
(i) Every compound has its components present in a definite ratio.
2.
(ii) Every compound has its own properties that differ from those of its components.
(iii)A compound may be a solid, liquid or gas
3.
(a) The substances that react in a chemical reaction are called reactants.
(b) The substance that are produced as a result of chemical reaction are called
products..
(c) Reactants are written on the left hand side of an arrow.
(d) Products are written on the right hand side of an arrow.
4.
A chemical equation is just a chemical reaction that is expressed using
chemical
symbols and formulae.
1. The chemical formulae of reactants (elements or compounds) are written on
the left hand side with plus (+) sign to distinguish each participating reactant.
Mg + O2
2. An arrow (" ) is placed just after ending position of reactants. The arrow means
yields to.
"
Mg + O2
3. To the right side of the arrow we write the chemical formulae of the
products.
4. Finally, we balance the equation
Mg + O2 " 2MgO.
5. When candle burns it results in the melting of wax which is aphysical change but
burning of wick is a chemical change.
B. Hots
1. In the cooler water is used which results in rapid rusting .
2. Bathroom fittings have electroplating as coating of corrosion resistant metals which
gives it a shining appearance.
3. Stainless steel has iron in it and pickle being acidic in nature increases the rate of rusting.
4. Burning of candle.
CHAPTER 7
Test Yourself, Page No. 67
1.
Breathing is a mechanical process of taking in atmospheric air oxygen inside the
body.
Breathing
Respiration
(i)
Mechanical process.
(i)
Chemical process.
(ii)
Energy is not released.
(ii)
Energy is released.
(iii)
Cells are not involved.
(iii)
Cells are involved.
2.
Respiration is necessary for the production of energy essential for life.
3.
In aerobic respiration, oxygen is utilized whereas in anaerobic respiration, oxygen is not
utilized to release energy from the food.
Criteria
1. Presence
of oxygen
2. Breaking
of food
molecule.
3. Formation
of Products
Aerobic
Respiration
Yes
Completely
broken
Carbon dioxide
+Water+Energy
4. Energy
Formation
5. Equation
More
Glucose
presence
CO +water
of oxygen 2
+energy
4.
5.
Anaerobic
Respiration
No
Partially
broken
Alcohol/Lactic
and Carbon
dioxide+Energy
Less
Absence
of oxygen
1. Glucose
Alcohol+ CO2
+energy
2. Glucose Lactic acid + CO2
Anaerobic respiration helps in production of alcohol, in bakery and in industries.
Fermentation is the process of breaking down of sugar into alcohol by yeast through
anaerobic respiration.
Test Yourself, Page No.70
1. The nasal cavity has Nostrils that are two air passages present in our nose.
2. Diaphragm is a flat muscular wall that provides base for the lungs.
3. Trachea (wind pipe)
Larynx is connected with a muscular pipe, at its lower end, called trachea or wind pipe.
The trachea is around 12 cm in length and around 2.5 cm in diameter. It is supported
by c-shaped, rings of cartilage which are c-shaped and prevent it from collapsing.
Alveoli provide large surface area for the exchange of gases.
Internal Respiration or Cellular Respiration
In the process of internal respiration food (glucose) is broken down
into simpler substances and energy is produced. During the process of inhalation air
reaches the lungs. Here oxygen from the air is diffused in the blood and combines
with haemoglobin to form oxyhaemoglobin. On reaching the tissue capillaries,
oxyhaemoglobin dissociates to release oxygen.
6.
Amount of nitrogen does not change during inhalation and exhalation
because nitrogen does not diffuse in the blood and its quantity remains
constant.
Test Yourself, Page No.71
1.
No, different animals have different ways to breathe.
2.
Amoeba respire by simple diffusion through cell membrane.
3.
Earthworms breathe through their moist skin.
4.
Fishes have gills for breathing. These gills are covered by operculum made up of
filaments richly supplied with blood.
5.
Frogs have thin and moist skin for the exchange of gases. They also have lungs for the
exchange of gases on land.
Test Yourself, Page No. 72
1.
Plants take in air through roots, stems and leaves.
2.
Respiration
Photosynthesis
4.
5.
(a)
(b)
(c)
(d)
3.
Oxygen is taken in and carbon
dioxide is released.
Releases energy from food.
Occurs in all living organism.
Occurs during day and night.
(a)
(b)
(c)
(d)
Carbon dioxide is taken
in and oxygen is
released.
Stores energy in food.
Occurs in green plants.
Occur during day only.
During night, plants release carbon dioxide as a result respiration. Therefore people are
advised not to sleep under a tree.
4. Lenticels are the special openings present on the stems of plants.
5. Roots of plants respire by the process of diffusion.
Formative Assessment, Page No. 72
A. 1. (d) 2. (c) 3. (d) 4. (b) 5. (a).
B. 1. Chemical 2. Aerobic 3. Trachea 4. Diaphragm 5. Inhalation, exhalation 6. Air.
C. 1. (c) 2. (e) 3. (d) 4. (a) 5. (b).
D. 1. Plants take in CO2 for the process of photosynthesis.
2. Stomata are the small pores present on the surface of leaves.
3. Respiration in which oxygen is utilized is called aerobic respiration.
4. Nasal cavity is the cavity present within the nasal passages and is separated from oral
cavity by a bony palate.
5. Alveoli are the tiny sac like structures present in the lungs.
6. Exhalation refers to giving out of air.
Summative Assessment, Page No. 74
1. Respiration refers to the process by which organisms take in oxygen
and use it to break down food for releasing energy. So respiration results in the release of
energy which is used for various processes of life. The process of respiration is as
follows:Internal Respiration
In the process of internal respiration food (glucose) is broken down into simpler
substances and energy is produced. During the process of inhalation air reaches the
lungs. Here oxygen from the air is diffused in the blood and combines with haemoglobin
to form oxyhaemoglobin. On reaching the tissue capillaries,oxyhaemoglobin
dissociates to release oxygen. This oxygen released in the tissues is then
utilized in breakdown of food, releasing energy and waste product carbon dioxide and
water.
2.
Criteria
1.
2.
3.
4.
Presence
of oxygen
Breaking
of food
broken
Formation
of Products
Energy
Formation
5. Equation
Aerobic
Respiration
Yes
Anaerobic
Respiration
No
Completely
molecule.
Partially
broken
Carbon dioxide
+Water+Energy
Alcohol/Lactic
and Carbon
dioxide+Energy
Less
More
Absence
of oxygen
Glucose presenceCO +water
of oxygen
+energy
1. Glucose
2
3.
2. Glucose
Alcohol+ CO2
+energy
Lactic acid + CO2
Fermentation is the type of anaerobic respiration in which yeast is used to break down
food items into other form.
(a) During this process sugar is broken down to produce alcohol.
(b) The process of fermentation is also used in making bread and cakes.
4. Lungs are located in the thoracic cavity. Diaphragm and the intercostal muscles, help in
contraction and expansion of the lungs during breathing. Diaphragm is a flat muscular
wall that provides a base for the lungs. Lungs look like huge pink sponges because they
contain tiny blood capillaries full of air spaces. Rib cage protects lungs from any physical
harm.
5. Breathing is completed in two phases.
Inhalation : When we inhale air, the rib muscles contract and the front ends of the ribs
move up-ward and outward. At the same time the diaphragm moves down-wards. In
this way a passage is created for air inside the chest cavity and the air from the
surroundings enters thelungs. The lungs get filled with air and hence the first phase of
breathing which is inhalation is completed.
Exhalation : During exhalation, the ribs move down-ward and in-wards, and at the
same time the diaphragm moves up-wards. In this way high pressure area is created and
air is forced to move out of the chest cavity. At this time the size of the lungs is reduced,
as they contract.
6. Internal Respiration
In the process of internal respiration food (glucose) is broken down into simpler
substances and energy is produced. During the process of inhalation air reaches the
lungs. Here oxygen from the air is diffused in the blood and combines with haemoglobin
to form oxyhaemoglobin.
On reaching the tissue capillaries, oxyhaemoglobin dissociates to release oxygen. This
oxygen released in the tissues is then utilized in the breakdown of food.
B. Hots
1. When we run for about one hour anaerobic respiration takes place which results in the
formation of lactic acid because of which crumps are formed which result in pain.
2. Nose has tiny hair and mucus membrane which trap the harmful microbes and dust
particles which is not so when we breathe through our mouth.
3. Breathing rate increases when we climb the staircase or do any physical work.
4. When dropped in water, the air trachea of insects get filled with water resulting on it's
death as it cannot breathe.
CHAPTER 8
Test Yourself, Page No. 78
1.
Weather refers to conditions of the atmosphere at a particular timeand place.
2.
3.
Meteorological department collect the relevant data and forecast the weather.
Weather forecast help to:
(a) prepare against bad weather.
(b) plan daily activities.
4.
Maximum temperature is recorded during the day and minimum during early morning.
Test Yourself, Page No. 82
1.
Three animals found in cold climate are polar bear, yak, sheep.
2.
Animals living in cold climate have long fur to withstand the low temperature even – 4oC.
3.
The camel has a thick skin, padded feet that help it to walk in hot sands. It stores fat in its hump and
drinks about 40 l of water.
4.
Tropical rain forests are found in Western ghats and Assam.
5.
Adaptation in Monkey
Many animals like monkeys and birds live on trees. A wide variety of monkeys are found in tropical
rain forests.
(i) They have long prehensile tail with the help of which they grasp branches and move from one
tree to another.
(ii) They have well developed hands with the help of which they can pluck fruits from the trees.
(iii) Their limbs also help them to move on the trees.
6.
Grass lands are the regions of moderate climate which receive low rainfall. These regions have tall
and strong trees and most of the parts are covered with grass.
Formative Assessment, Page No. 84
A. 1.
(d) 2. (d) 3. (d) 4. (c) 5. (d).
B. 1.
Meteorological department 2. Blubber 3. Perspire 4. Marshy 5. Ozone.
C.
D.
1.
1.
2.
3.
4.
T 2. F 3. T 4. T 5. F.
Climate refers to the average weather pattern of a place taken over a long period of time.
Main types of climate are- Cold climate, Hot climate and Moderate climate.
Four animals found in very cold climate are polar bear, sheep, penguin and seal.
Siberian birds come to India every year to avoid extremely cold winter of the
polarregion.
5. Animals found in desert are camels, insects, scorpions, snakes and moles.
6. Climate which is neither too hot nor too cold.
7. Some animals hibernate to minimize the loss of heat from their body.
8. Wide variety of herbivores are found in grass lands because these regions are covered
with long grass, so there is plenty of food for them.
Summative Assessment, Page No. 85
A. 1. Animals found in cold region have following features(a) White long fur to hide and protect themselves.
(b) Strong sense of smell to locate the enemy.
(c) Long sleep (hibernation) during winters.
(d) Blubber under the skin.
(e) Thick skin.
2. (i) The thick skin of camel protects it from seorching sun and waterloss. (ii) Paddedfeet
of camel help them walk easily on the sandysurface of the desert. (iii) Camel
does not perspire, so there is no waterloss through sweating. (iv) Camels have
hump on theirback which store fat. This fat can convert into metabolic water when
needed.(v) A camel can drink about 40-50 litered of water at a time. Camel can
remain without water for several days.
3. Moderate climate is neither too hot nor too cold. These regions also experience the
change of seasons. Few of these areas experience heavy rainfall also. Due to this
heavy rainfall and warm climate wide variety of plants and animals are found here.
4. Factors affecting climate (Natural)Altitude
It is the height of a place above the sea-level. As you know when we move upward in the
sky the temperature falls 1oC at every 132 metres. So, the temperature at higher altitudes
is low. That’s why the peaks of the mountains remain covered with snow throughout the
year.
Distance from the sea
The climate of the coastal areas is pleasant. It is because of the land breeze and sea breeze.
Land gets heated more rapidly than water so during the day time cool air from the sea
blows to land and keep the temperature pleasant. During the night the land becomes
cooler early than sea water. So, during the night the cool air from the land moves
towards the sea.
5.
Man-made changes in climate
In today's world man has brought industrial revolution to satisfy his ever increasing
demand. As a result, man has started over exploiting resources which has further
resulted in pollution and depletion of resources. These factors have also modified the
environment and climate.
6.
Adaptation in Frogs
Amphibians like frogs can live in water and on land both. They generally live on land.
But they lay eggs in the water of ponds and ditches.
B.
Hots
1. Birds migrate at specific time in search of favourable conditions.
2. Penguins live in groups to get warmth.
3. During dry weather, air is able to absorb water from the clothes quickly.
4. Long and prehensile tail helps arboreal animals to maintain a balance.
CHAPTER 9
Test Yourself, Page No. 90
1.
Soil is the uppermost layer of the earth's crust.
2.
Humus refers to organic matter like dead and decaying remains of plants and animals
present in the soil.
3.
Four organisms found in the soil are bacteria, earthworms, snails ant ants.
4.
Chemical weathering refers to the process of changing one type of mineral into another
by flowing water or rain or temperature.
5.
B-Horizon or sub-soil: It is the layer present just below the top soil.
It contains less humus as compared to top soil and therefore it is less fertile. It is made up
of rock bits and some minerals which are soluble and iron oxide.
6. Sandy soil has very low or no water retention capacity. Therefore it is not good for
cultivation.
Test Yourself, Page No. 91
1. Alluvial soil has silt in it which makes it fertile.
2. Black soil is good for the cultivation of cotton. Therefore it is also called black cotton soil.
3. Red soil is red in colour due to the presence of iron oxide in it. Therefore it is also called
red soil.
4. Laterite soil is good for the cultivation of tea and coffee.
5. Desert soil is found in parts of Gujarat and Rajasthan.
6. Mountain soil is very fertile due to heavy rainfall and abundant amount of humus.
Test Yourself, Page No. 94
1. Different properties of soil are:
(a) Presence of moisture.
(b) Percolation of water in the soil.
(c) Absorption of water.
2. Soil plays an important role in plant growth. It is a habitat for many organisms. It also
helps in percolator of water and retain it.
3. The process of carrying away the top soil by agents like wind, water etc. is called soil
erosion.
4. Soil erosion can be prevented by planting more trees, doing step farming, crop
rotation and constructing dams.
5. Soil fertility can be replenished by:
(a) Adding manures to the soil.
(b) Adding fertilizers to the soil.
(c) Crop rotation.
(d) Field fallow.
Formative Assessment Page No. 95
A. 1. (b) 2. (b) 3. (b) 4. (a) 5. (d).
B. 1. Humus 2. Mature 3. Pieces of rocks 4. Loamy 5. Alluvial.
C. 1. (d) 2. (e) 3. (a) 4. (b) 5. (c).
D. 1. Alluvial soil 2. Black soil 3. Red soil 4. Desert soil.
E. 1. Soil of C-horizon is called weathered rock.
2. Size of sand particle is O to 2mm in diameter.
3. Alluvial soil is made up of silt.
4. Three states where black soil is found are Maharashtra, some parts of
Gujarat and Tamil Nadu.
5. Afforestation refers to planting more and more trees.
Summative Assessment, Page No. 97
A. 1. Soil is made up of organic and inorganic matter and micro organisms.
2. Natural process that helps in breaking of rocks is called weathering. Some natural
factors of weathering.
1. Flowing water
Flowing water breaks down the rocks into smaller particles.
2. Growth of roots
In some cases it has been found that the roots of vegetation, penetrating deep
down in search of water and nutrients push the rocks apart. In this way rocks
break down in smaller particles.
3. Arrangement of soil in different layers is called soil profile and each layer is called
orizon.
Different horizons of soil are:
(i) A-Horizon or top soil: It is the topmost layer of soil which.
is rich in humus and minerals needed by plants for their growth. It is fertile.
(ii) B-Horizon or sub soil: It is the layer present just below the top soil. It contains less
humus as compared to top soil and therefore it is less fertile. It is made up of rock
bits and some minerals which are soluble and iron oxide.
4.
Differentiate between Sandy Soil and Loamy Soil
Sandy Soil
1. Contains sand particles of
large size.
2. Space between the particles
2.
are quite large.
3. Water holding capacity is negligible.
4. It can be ploughed easily.
5. It cannot hold the nutrients.
5.
5.
6.
Loamy Soil
1. Contains clay, sand and silt in right
proportion.
Sufficient space is present
between the particles.
3. Right water holding capacity.
4. It can be ploughed easily.
It can hold necessary nutrients
required by the plant.
Alluvial soil is an important soil of India because it contributes the largest share to its
agricultural wealth. It is made up of silt brought by rivers from the mountains. It is very
fertile because of its loamy textureand lot of humus. It is good for growing wheat, rice,
pulses, vegetables, sugarcane etc.
Soil is important because of the following reasons:
(i) It helps in plant growth. All plants depend on soil directly for water, minerals, humus
and physical growth.
(ii) Habitat for organisms soil provides habitat for millions of tiny organisms like
worms,burrowing insects, arthropods earthworms and snails.
(iii) Soil acts as a facilitator for percolation and retention of water. Soil contains sufficient
amount of water. Water holding capacity of soil helps it to serve as a reservoir of
water. This important property of water also help to grow vegetation.
7.
The process of carrying away the top soil by these agents like wind, water etc. is called
soil erosion. It is a natural process.
Causes of soil erosion
Besides natural reasons activities of man play an important role in soil erosion. These
are as follows:
(i) Deforestation: Deforestation refers to large scale cutting of tress. Roots of the soil
bind the soil particles and do not allow them to be carried away. But due to excessive
cutting of tress, soil become exposed to various agents of erosion and is blown away
turning the land barren.
(ii) Over grazing in forest: Many animals like cattles are left in the field for grazing.
These cattles eat up most of the plants of that land. Not only this they pull out the plants
including grasses and also destroy it. As a result soil becomes loose and soil erosion takes
place.
(iii) Poor farming methods: Poor farming methods like deep ploughing, leaving the land
uncultivated after ploughing and tilling, in ability to rotate the crops etc. contribute to soil
erosion.
(iv) Forest fires: Sometimes there is fire in the forest that results in the loss of vegetation
resulting in soil erosion.
(v) Clearing the forest : Clearing the forest to make the land available for farming or
constructing building. It results in the exposure of soil to various agents of soil erosion
resulting in the removal of top soil.
B. Hots
1. Because sandy soil has very low water retention capacity.
2. Excess of fertilizers will make the soil acidic or alkaline.
3. Dead and decaying plants and animals and their wastes get added to top soil resulting in
more humus.
4. (a) Dams control flood.
(b) Dams are used to generate electricity.
(c) These also provide water.
CHAPTER 10
Test Yourself, Page No. 102
1.
Vascular system – Transportation system of plants is called vascular system.
2.
Imbibition – The phenomenon of absorption of water by both living and dead tissues
of plants, when soaked in water.
3.
Xylem and phloem are the two components of vascular bundle.
4.
The process by which plants loose water through their leaves, in the form of water
vapour.
5.
Xylem helps to transport water as well as minerals and distributes it to plants through
phloem.
6.
Carbohydrates are distributed in plants through phloem.
Test Yourself, Page No. 103
1.
Transpiration is the process by which plants lose water through their leaves.
2.
Transpiration helps in the transport of water and minerals upwards.
3.
Plants start wilting when the rate of absorption of water is lower than the rate of
transpiration. It results in drooping of leaves and hence wilting.
4.
Permanent wilting occurs in the region where soil is deficient in water.
It usually kills the plant unless the soil is watered soon after the
appearance of the first symptoms of wilting.
Formative Assessment, Page No. 104
A. 1. (b) 2. (b) 3. (c) 4. (b).
B. 1. Dead 2. Prepared food 3. Minerals 4. Swell 5. Permanent.
C. 1. F 2. T 3. F 4. T 5. T
D. 1.
Transportation refers to carrying raw materials to the leaves for making
food and again carrying prepared food to different parts of a plant.
2.
A.
Osmosis – Movement of water molecules from a region of lower concentration to the
region of high concentration through the semi- permeable membrane.
3.
Water reaches the leaves through vascular tissue.
4.
Xylem and phloem are packed as compact mass. This compact mass is called vascular
bundle.
5.
Plant leaves droop and start wilting.
6.
Transportation in plants helps to carry raw materials to the leaves and distributing the
prepared food in different parts of a plant.
Summative Assessment, Page No. 105
1. Difference between Diffusion and Osmosis.
Diffusion
(a) Diffusion is movement of
solute molecules.
(b) Movement is from the region of
greater concentration to lesser
concentration.
(a)
(b)
Osmosis
Osmosis is the movement
of water molecules.
Movement is from lower concentration
to higher concentration.
2. Difference between Xylem and Phloem:
(a)
(b)
(c)
Xylem
Phloem
Xylem tissue helps in the
(a) Phloem tissue helps in the
transport of water and minerals.
transport of food.
Made of dead cells.
(b) Made of living cells.
Movement is in upward direction. (c) Movement is in both upward and
downward.
3.
Plant roots take in water and dissolved minerals from the soil through
root hair. Root hair take in water through a combination of diffusion
and osmosis. Water passes from the soil into the cell by the process of
osmosis. Dissolved minerals, in the form of ions, also pass from the soil
solution through the cell membrane into the cells.
B. Hots
1. Water can rise up in tall trees due to transpiration and vascular bundle.
2. Leaves are absent in desert plants. It reduces the loss to water due to
transpiration. These plants have green and fleshy stem for preparing
the food.
A.
B.
C.
D.
Practice Paper for Formative Assessment-II
Based on Chapter 6 to 10, Page No. 106
1. Chemical 2. Perspire 3. Lenticels 4. Top soil 5. Imbibition.
1. F 2. F 3. T 4. T 5. F.
1. To prevent rusting.
2. In search of favourable conditions .
3. Nose has mucus membrane and hair which trap the harmful particles during breathing.
4. Transport system consists of a network of vessels therefore also called vascular system.
1. Physical change – A change that involves change in physical properties only e.g.
shape, size, colour, state etc.
Characteristics of a physical change
(i) During a physical change only physical properties of a substance change.
(ii) As a result of a physical change no new substance is formed.
(iii) Physical changes are temporary and reversible.
(iv) During physical changes energy is neither absorbed nor evolved. If it is, in very
small amount.
(v) There is no change in mass during a physical change.
Difference between Aerobic Respiration and Anaerobic Respiration.
Criteria
Aerobic
Anaerobic
Respiration
Respiration
1. Presence
Yes
No
of oxygen
2. Breaking
Completely
Partially
of food
broken
molecule.
3. Formation
Carbon dioxide
Alcohol/Lactic
of Products
+Water+Energy
and Carbon
dioxide+Energy
4. Energy
More
Less
Formation
broken
5. Equation
Absence
presence
of oxygen
Glucose
CO2 +water
of oxygen +energy
1. Glucose Alcohol+ CO2
2.
+energy
2. Glucose Lactic acid + CO2
3.
4.
Adaptation in elephant
Elephants are well adapted in rain forests:
(i) It uses its long trunk as a nose. It has strong sense of smell.
(ii) Its huge size help them to be safe from carnivores like tigers, lion.
(iii) It uses its trunk to tear the bark from trees. They eat these bark.
(iv) Long ears help them to hear even soft sounds and also cool them in the hot
and humid climate of the forests.
On the basis of texture, soil is classified as sandy, clayey and loamy soil.
Clayey Soil
Contains clay particles of
size
.
(ii) Space between the particles is
(i)
Water holding capacity is
(iii)
good.
(iv) It cannot be ploughed easily
(v) It can hold the nutrients
required by the plants.
E.
Loamy Soil
Contains clay, sand and silt in right small
proportion
(ii)
Sufficient space is present quite less.
between the particles.
(iii)
Right water holding capacity.
(iv)
It can be ploughed easily.
(v)
It can hold necessary
nutrients required by the plants.
(i)
Sandy Soil
1. Contains sand particles of large size.
2. Space between the particles is quite large.
3. Water holding capacity is negligible.
4. It can be ploughed easily.
5. It cannot hold the nutrients.
5. Effects of transpiration
Transpiration creates low pressure in upper portion of the plants that helps in
transportation of water and minerals upward.
It is responsible for maintaining turgidity and thus helps in growth of plants. It has
cooling effect on the plant and maintains proper temperature for other physiological
activities.
Across
1. Weathering 2. Electrolysis 3. Phloem 4. Hibernation
Down
1. Wilting 3. Trachea 4. Atom 5. Humidity 6. Horizons.
F.
1.
(d) 2. (b) 3. (b) 4. (d) 5. (b).
Practice Paper for Summative Assessment-I.
Based on Chapter 1 to 10, Page No. 106
A. 1. When a heat source such as a fireplace or radiator near the floor of room operates, the
warm air first rises then cools, falls and is warmed again, forming a cycle called a
convection current.
2. Neutralisation reaction is a reaction between an acid and a base.
3. Reaction in which more reactive metal displaces a less reactive metal from its compound
is called displacement reaction.
4. Tail that helps the animals to grasp the branches and maintain the balance.
5. Water soluble bases when combine with water form hydroxide. These bases are called
alkalies.
6. Chemical weathering refers to the process of changing one type of mineral into another
by flowing water or rain or temperature.
B. 1. Heat gets transferred by conduction, convection and radiation.
2.
Indicator
Base
(i) Methyl orange
yellow
(ii) Red litmus
blue.
3. Crystallisation is the process of obtaining large crystals of pure substances from their
solution. It is an example of a physical change.
4. (i) Components of a compound are present in a definite ratio.
(ii) Every compound has its own properties that differ from those of its compounds.
5. Cokeroach has a system of tubes called tracheae that have small openings called
spiracles through which air enters their body during respiration.
C. 1. They have a different kind of digestive system which can digest grass which contains a
high amount of cellulose. Human beings cannot digest cellulose. The ruminants have
four chambers in their stomach.
2. The production of wool fibre comprises various processes, these processes are as
follows:
1. Rearing: Sheep are cultured or reared because of their wool. In India
they are reared in hills of Jammu and Kashmir, Himachal Pradesh, Uttrakhand, Sikkim
and Arunachal Pradesh.
2. Shearing: Wool is the long and soft hair of some animals. The thick coat of
hair a sheep’s body is called ‘fleece’. This fleece is removed from its body by using
clippers. Removing animal hair from its body for commercial purpose is called shearing.
After the fleece is removed, it is examined for quality.
3. Scouring: This is the first and the most important process. In this process the sheared
wool is washed properly using detergent and chemicals to make it clean, soft and germ
free. This is known as scouring. Thereafter, it is made smooth by oiling.
4. Sorting: It means separating fibres of different textures.
5. Carding: It is the process in which washed wool is sent into a carding machine. The
carding machine combs the loose wool fibres into a sheet. Then the sheet is twisted into
ropes called ‘sliver’. The sliver is then stretehed and twisted into yarn.
6. Yaran is then dyed in different colours. Finally the yarn is wound to form balls of
wool. This wool is then used to make woollen garments. The quality of wool is
determined by the colour, fineness, the number of crimps per unit length and the
cleanliness of the fibre.
v
3. The thick skin of camel protects it from scorching sun and water loss. Padded feet
of camel help them walk easilyon the sandy surface of the desert. Camel does not
perspire, so there is no water loss through sweating. Camels have hump on their back
which stores fat. This fat can convert into metabolic water when needed.
A camel can drink about 40-50 litres of water at a time.
4. The process of Carrying away the top soil by agents like wind, water etc. is called soil
erosion. It can be prevented by:
(i) Afforestation (ii) Step farming (iii) Crop rotation
5.
D. 1.
2.
(iv) Preventing overgrazing (v) Constructing dams.
Plants have a well developed network of tubes that carry raw materials to the leaves for
making food and again carry prepared food to different parts. This system is called
transportation system. These tubes are made up of special cells called vascular tissue
which consists of xylem and phloem. Xylem helps in the transport of water and minerals
and phloem helps in the transport of food.
Process of Photosynthesis
1.
The Plants contain green pigments in their leaves, called chlorophyll. These
green pigments trap sunlight during the day and convert light energy into
chemical energy. Thus, Sun is the ultimate source of energy for all living
organisms.
2. Water absorbed by the roots is sent to different parts of the plants. During the
process of photosynthesis water molecules present in the cells break up and
oxygen present in water is set free.
3. The hydrogen from the water molecules combines with carbondioxide (CO2)
from the environment to form glucose, a simple sugar.
Plant take in CO2 through small pores present in their leaves called stomata.
4. The chemical energy is trapped within the glucose molecules.
Different enzymes produced in alimentary canal and their action are as follows:
Enzyme
Action
Mouth
Starch Sugar
Saliva has enzyme amylase
Digestive enzyme pepsin
Digestion of protein
Stomach
Small intestine
Bite juice from live.
Digestion of fats
Pancreatic juice
from pancreas
E.
1.
Difference between Respiration and Photosynthesis
1.
2.
3.
4.
2.
1.
2.
3.
3.
Digestion of
carbohydrates.
Respiration
It is a biochemical process which
involve the complete break down
of food.
It occurs inside the cell.
Energy is released duringrespiration.
Enzymes are involved in the
process of respiration.
1.
2.
3.
4.
Breathing
It is a physical process which involve
exchange of gases.
It does not involve cell.
Energy is not produced during
breathing.
Enzymes are not involved in the
process of breathing.
Difference between Weather and Climate
Weather
Weather refers to conditions of the 1.
atmosphere at a particular time and
place.
It is restricted to a smaller area.
2.
Weather of a place changes suddenly 3.
sometimes even hour to hour.
Climate
Climate refers to the average weather
pattern of a place taken over a long
period of time.
It is applicable to the larger area.
Climate of a place remains same over
a long period of time.
Difference between Clinical Thermometer and Laboratory Thermometer.
Clinical Thermometer Short
Laboratory Thermometer Long
(i) 0 °C to 100°C
(i) 35° C to 42° C
(ii) Bulb should remain in contact with
(ii) Before taking the reading remove the
the substance while reading is
thermometer from the body.
taken.
(iii) Magnifying effect is mercury column (iii) Simple, cylindrical.
but only at certain angle.
(iv) Capillary has a constructions called (iv) Capillary is straight.
kink.
F.
1.
The soil broadly consists of the following components :
(i) Inorganic materials: Soil contains inorganic materials i.e.,
mineral particles. These are derived from some parent material. The soil is
formed from rocks by fragmentation or weathering.
(ii) Organic materials: Soil also contains organic materials in the form of humus.
It is derived from dead organism by the process of decomposition.
(iii) Air and water: The gaps between the soil particles contain air and water. Air
and water are important constituents of soil. These are used by plants and
organisms living in the soil for their survival.
(iv) Organisms : Soil also contains small living organisms such as bacteria,
fungi, algae, protozoans, earthworms, snails, ants, etc. These organisms help in
increasing the fertility of the soil and making it porous.
CHAPTER 11
Test Yourself, Page No. 111
1.
Blood.
2.
Circulatory system is the collection of organs that help in the transport of blood in
humans and animals.
3.
RBC, WBC and blood platelets.
4.
Blood helps to regulate the body temperature by distributing the heat equally in the
different parts of the body.
Test Yourself, Page No. 113
1.
Blood Vessels
There is a complicated network of thin blood tubes all around our body. These
muscular tubes are called blood vessels. There are three types of blood vessels. (i)
Arteries (ii) Vins (iii) Capillaries.
2. Thin walled vessels that carry blood with is carbon dioxide from different parts of the
body to the heart.
3. Walls that divide the heart into two halves.
4. Ventricles are the lower two chambers of the heart which distribute the blood.
5. In lungs reoxy genation of blood takes place. Blood circulates in our body through blood
vessels.
Test Yourself, Page No. 114
1.
The rhythmic contraction and relaxation of heart produce 'LUB' and 'DUB' sound that
constitute a heart beat.
2.
70-72 times in a minute.
3.
The number of pulse beats per minute is called pulse rate.
4.
Pulse rate increases at the time of physical exercise.
5.
Wrist, ankile temple etc. are the suitable places to note down the reading of pulse rate.
Test Yourself, Page No. 114
1.
Cyclosis is a steaming movement of the cell substance.
2.
In sponges water circulates from surrounding medium through certain channels in their
bodies.
3.
Frogs and lizards.
4.
Open circulatory system is a type of circulatory system which does not
have blood vessels and haemoglobin. In such a system blood flows in open space in the
body e.g. in insects such as cockroach , ant etc.
Test Yourself, Page No. 117
1.
CO2, nitrogenous wastes like ammonia, urea, uric acid in the form of urine and sweat.
2.
Kidneys Human, kidneys are paired bean shaped organs about 10 cm long. These
aredark red in colour and are present in the abdomen, just above the waist on either side
of the backbone.
Each kidney consists of about one million functional units called nephons.
3. (a) Presence of glucose in the urine.
(b) Presence of blood in the urine.
4.
Dialysis is an artificial filtration of blood through semipermeable membrane to remove
urea and other wastes periodically.
Test Yourself, Page No. 118
1. By the process of diffusion.
2. Excretory organs are as follows:
(i) Insects-Malphigian tubules
(ii) Humans- kidneys
(iii) Amoeba- contractile vacuole
(iv) Earthworm-nephridia.
3. Nephridia are the excretory organs of earthworm. These are the coiled tubes which
throw wastes into the intestine of the earthworm or directly to the outside in the form of
urea and ammonia.
Formative Assessment, Page No. 118
A. 1. (d) 2. (b) 3. (a) 4. (a) 5. (d).
B. 1. Water, blood 2. Veins 3. Haemolymph 4. Urea, uric acid
5. Malphigiran tubules.
C. 1. T 2. T 3. F 4. F 5. T.
D. 1. (4) 2. (5) 3. (2) 4.(6) 5. (3) 6. (1).
E. 1. Blood platelets are the important components of blood because these help to clot the
blood at the site of injury and prevent further loss of blood.
2. (a) Heart beat- contraction and relaxation of heart is associated with
the circulation of blood and therefore this pumping of heart can be heard as
are gularthumping sound. These are calledheart beats.
(b) Haemoglobin is a pigment present in RBC'S and help in the transport of oxygen
and carbon dioxide.
3. Pulse rate indicates the number of heart beat. A normal person has a pulse rate of 72
time per minute and if it is less or more it reflects some health problem.
4. Capillaries act as a medium between arteries and Veins. These help in the exchange of
materials between the blood and the cells of the tissues.
Summative Assessment, Page No. 120
A. 1. Composition of blood
It is composed of a fluid portion plasma (50-55% of the volume) and three types of
corpuscles (45-50% of the blood volume) namely RBC, WBC and blood platelets.
Plasma
It mainly consists of light yellow fluid with 90-92 % of water, 6-9 % of proteins and 1 % of
dissolved substances.
RBC
Red Blood Cells or RBC consists of haemoglobin, a pigment which transports oxygen
and carbondioxide. These cells are formed in the bone marrow.
2. Heart
Heart is a muscular organ which is considered as most sensitive part of our body. It is as
large as the closed fist and is shaped like a cone.
It lies slightly to the left in our chest cavity, between the lungs. Its average weight is about
340 grams in men and 255 grams in women.
Human heart is enclosed in a double sac called pericardium. Walls of heart are formed
of cardiac muscles. These muscles contract and relax throughout the life and help to
pump the blood into artries so that it can be transported to all the parts of the body.
Human heart is four chambered. A wall called septum divides the heart into two halves,
left half and right half which called article and the lower chamber prevents the mixing of
oxygenated and deoxygenated blood of the heart. Each half in turn is divided into an
upper chamber called auricles and the lower chamber is called ventricle.
Arteries to head
and arms.
Left ventricle
Coronary artery
Left Atrium
Right
ventricle
Right Artrium
Structure of Heart
3.
1.
2.
3.
4.
5.
6.
Difference between Arteries and Veins
Arteries
Thick walled vessels.
Lumen is narrow.
Carry oxygen rich blood from the
heart to other parts of the body.
Deep seated and cannot be seen
easily.
These are red in colour
Walls of arteries are impermeable.
1.
2.
3.
4.
5.
6.
4.
Veins
Thin walled vessels.
Lumen is wide.
Carry blood with is carbon
dioxide from different parts of the
body to the heart.
Superficially placed and can be
seen easily.
These are bluish green.
Walls of veins are impermeable.
Dialysis
If one kidney gets damaged the second kidney can fulfil the need but if both the kidneys
get damaged the excretory system fails to remove toxic wastes which can be fatal for the
patient. Doctors keep such patients on dialysis to remove toxic wastes through artificial
methods. Dialysis is an artificial filtration of the blood through semi-permeable
membrane to remove urea and other wastes periodically. However, there is another way
to treat such patients. This is kidney transplant in which patient's kidney is replaced by
donor’s kidney.
5. Excretion in Human Beings
Human excretory or urinary system consists of a pair of (i) a pair of kidneys (ii) a pair of
ureters, (iii) one urinary bladder and (iv) a urethra.
Kidneys Human, kidneys are paired bean shaped organs about 10 cm long. These are
dark red in colour and are present in the abdomen, just above the waist on either side of
the backbone. Each kidney consists of about one million functional units called
nephrons. Each nephron has Bowman’s capsule at one end and the rest part of the
nephron is differentiated into a coiled proximal convoluted tubule, a ‘U’ shaped thin
tubule and a distal convoluted tubule. Nephrons filter blood which passes through the
kidneys and the waste products are collected here in the form of urine.
Ureter
It is a narrow tube which transports urine. It runs from the inner side of each
kidney. It joins the two kidneys to the urinary bladder.
Urinary bladder
It is a muscular bag in which urine collects. The ureter transports
urine to this urinary bladder. It is situated in the pelvic cavity of man.
Urethra The urine collected in urinary bladder passes through a muscular tube called
urethra. This is a very thin tube and its opening is regulated by sphincter muscules.
6. Amoeba
–
Ammonia
Earthworm
–
Urea and ammonia
Cockroach
–
Uric acid
Fishes
–
Ammonia
Birds
–
Uric acid
Lizards
–
Uric acid
B. HOTS
1. Removal of undigested food is egestion but excretion is removal of nitrogenous waste.
2. Arteries pump the pure blood in the body parts therefore they are thicker as compared to
veins.
3. We sweat in summer because sweat evaporates leaving the body cool which is required
during summer not winter.
4. Old people are thin skinned so veins become prominent.
5. Plants have a well developed network of tubes or vessels present everywhere in plants
body. These tubes help in sending water and mineral salts to the leaves and prepared
food to different parts of the plant.
CHAPTER 12
Test Yourself ,Page No. 124
1.
Reproduction is one of the life processes in which a living organism produces its own
kind.
2.
Reproduction is important to continue the race, increase the population, maintain
ecological balance and in evolution.
3.
Roots, stems and leaves are the vegetative parts of a plant.
4.
Different methods of a sexual reproduction are fission, budding, fragmentation spore
formation, regeneration and vegetativepropagation.
Test Yourself, Page No. 126
1.
Vegetative reproduction refers to the reproduction from vegetative parts of a plant
without the help of any reproductive organ.
2.
Roots, stems and leaves.
3.
Cutting, layering, grafting and tissue culture.
4.
Tissue culture - A small piece of tissue is taken from the top of the plant. It is placed in
the artificial nutrient medium which contain hormones. It make the cells divide and form
unorganised mass of cell which is transferred to another medium for multiplication. As a
result of it, a new plantlet is obtained which is grown in moist soil. etc.
5. Advantages of Vegetative Propagation
(i) New plants obtained are genetically identical to their parents.
(ii) This method is quicker and takes lesser time.
(iii) It is economical method.
(iv) Plants grown by this method need less attention as compared to plants grown
from seeds.
(v)
This method is very useful for the plants which do not produce seeds and for those
plants also whose seeds are not viable.
Test Yourself, Page No. 128
1. Zygote is a product of fusion of male and female gamete.
2. Carpel and stamen.
3. Pollen grains are male cells produced in anthers.
4. For pollination insects like bees and butterflies or lizard carry the pollen grains from the
anther to the stigma.
5. After fertilization ovule develops into a seed.
6. Animals act as an important medium for the dispersal of seeds. Some seeds possess
spines or hooks which enable them to stick to the body of animals and are carried from
one place to other. Fruits are eaten by animals and birds and the enclosed seeds may
be taken to distant places before they are passed out in their excreta without any damage
to the embryo.
7. Seeds need water for gemination.
Formative Assessment, Page No. 128
A. 1.
(b) 2. (a) 3. (a) 4. (a) 5. (d).
B. 1.
Reproduction 2. Roots 3. Zygote 4. Ovary 5. Seed.
C. 1.
(d) 2. (a) 3. (b) 4. (f) 5. (c) 6. (e).
D. 1.
T 2. T 3. T 4. T 5. F.
E. 1.
Reproduction is a life process in which a living organism produces its own kind.
2.
Yeast and hydra reproduce by budding.
3.
It is the process of reproducing from the vegetative parts.
4.
Asexual reproduction is a type of reproduction in which a plant reproduces its kind
without seeds.
5.
Transfer of pollen grains from the anther to the stigma of a flower.
6.
Fertilization is fusion of male and female gamete.
Summative Assessment, Page No. 130
A. 1. Budding
In this method of a sexual reproduction an outgrowth or a bulb like projection appears
on the body of parent organism. This is called bud. Bud grows into an offspring and then
gets detached from the parent and becomes an independent organism. It may remain
attached to the parent organism and reproduce again and again to form a colony.
Examples of budding are yeasts, Hydra etc.
2.
3.
4.
The different type of vegetative propagation ire or follows:
Vegetative propagation by modified roots
Plants store food in their swollen roots. When these roots are burried in the soil, a new
plant emerges e.g. Dahlia, Asparagus, Sweet potato.
Vegetative propagation by modified stems
Some plants reproduce through their stems e.g. potato, ginger, sugarcane, gladiolus etc.
These are swollen and when planted they form new plants.
Vegetative propagation by leaves
Some plants such as Bryophyllum, Begonia etc. multiply by their leaves. New plantlets
develop from the edge of these plants. When they come in contact with the soil they get
detached from the leaves and grow into new plant.
Cutting
Small piece of a stem of a plant, having some leaf, buds is called cutting. When it is
planted into moist soil, it develops root and grows into a new plant e.g. in sugarcane,
rose, Bougainvillea, cactus.
Layering
In this method, a lower branch of the plant is bent down and is covered with moist soil. It
develops root and a new plan tlet is formed e.g. Jasmine, Bougainvillea etc.
Grafting
In this method cutting (scion) of one plant is placed over the stump (stock) of other plant
and both parts are tied together with a thread so
that their cambium get fused into one. As a result of it a new variety of plant is obtained
which has the desired characteristics. e.g. flowering plants and fruit bearing plants.
Difference between Asexual reproduction and Sexual reproduction.
Asexual reproduction
(a) Only one parent is required.
(b) Takes place in unicellular organism.
5.
Sexual reproduction
(a) Two parents are required.
(b) Different types of sexual takes place in
multicellular organism.
The pollen grains are carried from the anther to the stigma. This process is called
pollination.The process of pollination does not occur itself. It is triggered by insects or winds.
Insects : Many insects feed on the nectar of flowers. Some other insects attracted by the
colour and odour of the flowers. When they sit on the flowers the pollen grains stick to
their body. When these insects visit some other flowers the pollen grains fall in these
flowers which trigger pollination. The insects involved in pollination are bee, butterfly
and moth.
Wind : Wind also blows pollen grains from one flower to another. But, the wind
pollination generally occurs in the flower with small or no petals such as wheat, corn,
grasses, etc. These flowers expose pistil to the wind and carry on the process of
pollination.
6. Formation of seeds and fruits
After the development of the zygote, the flower slowly withers and only the ovary is left
back. The zygote in each ovule slowly develops into a seed. But in fruit plants, the ovary
changes into a fruit. It ripens to becomes sweet juicy and edible.
7.
Germination of a Seed
Germination of a seed starts when it takes in water. It helps the enzymes inside the seed
to be active. They digest the stored food and make it soluble. This soluble food slowly
percolates to the root (radicle) and the shoot (plumule). So, both of them begin to grow.
As for the root, it pushes down into the soil and begins to absorb soil-solution for making
food.
The shoot, when it has broken out above the soil, gets sunlight and becomes green.
Soon it begins to make food through photosynthesis using the soil-solution sent up by
the root. As a result, it grows to be a seedling and then into a plant.
B. HOTS
1. In castor and balsam fruits burst when they get ripen. This results in scattering of seeds in
adjoining areas.
2.
3.
It will not pollinate.
Flowers which are pollinated by insects are more attractive.
CHAPTER 13
Test Yourself, Page No. 133
1. Bulbs, computer, television, trains, lift etc.
2. Electricity that does not flow is called static electricity.
3. Thomas Brown coined the word electricity.
4. Electricity flows when there is flow of electrons along a conductor.
5. One end of electric circuit is earthed to give a potential difference.
6. An electric circuit through which an electric current can flow is called closed circuit.
7. Basic requirements for an electric circuit are electric cell, electric bulb, battery, switch in
ON and OFF position.
Test Yourself, Page No. 134
1. Resistor is a device that gives resistance to electric flow.
2. Terminal is a metal nut on a screw thread through which wires are connected.
3. Ammeter is used to measure the amount of electricity passing through an electric circuit.
4. Voltmeter is a device used to measure potential difference.
Test Yourself, Page No. 137
1. Heating effect of electricity is used in iron, electric heater, hot plate, toaster, water heater,
geyser, electric kettle etc.
2. Tungsten offers a great resistance to electric current and it has a high melting point also.
Therefore it is used in electric bulb.
3. When a wire breaks in a circuit or a connection is faulty, a leak of electric current is likely
to occur which may cause fire. A break of this kind is known as short circuit.
4. In a bulb filament is coiled to shorten the length and lessen the resistance.
5. Fuse is a piece of a metal wire having low melting point.
6. Different types of fuses are kit-kat fuse and cartridge fuse.
7. Fuse is used to avoid damage due to short circuit.
8. Electromagnet is a piece of iron wounded by wire through which electric current it
passed. It acts like a magnet.
Formative Assessment, Page No. 138
A. 1. (b) 2. (a) 3. (a) 4. (c) 5. (d).
B. 1. Charged 2. Closed, open 3. Terminal 4. Energy 5. Electric current.
C. 1. Electric bell is used at doors.
2. Ammeter is used to measure the amount of electricity passing through an electric circuit.
3. Kit kat fuse saves us from electric shocks.
4. Electric bulb is used for getting light.
D. 1. T 2. T 3. F 4. F 5. T.
E. 1. Current electricity – It is the form of energy that makes all machines work.
2. Electric circuit – A continuous path of conductors and other electrical equipments.
3. Galvanometer is a device used to detect the flow of electric current.
4. A break in a circut is known as short circuit.
5. Devices in which electromagnets are used such as generators, motors,
mixer grinders, cranes, telephones etc.
6. When there is a potential difference between two poles, electrons flows from one
conductor to another.
Summative Assessment, Page No. 139
A. 1. Closed circuit
An electric circuit through which an electric current can flow is called a closed circuit.
The bulb glows in a closed circuit.
Open circuit
An electric circuit through witch electric current cannot flow is called an open circuit.
2.
Heating Effect of electric current
When an electric current passes through a conductor, it loses a part or whole energy.
This energy is converted into heat. Actually, each and every conductor gives resistance
to current when it passes through them. The magnitude of resistance depends upon the
material used to make the conductor. For example, a wire made up of copper gives less
amount of resistance as compared to the wire made up of iron. It is because copper is a
better conductor than iron. Thus more resistance a conductor offers the more is the heat
generated.
3. Working of an electric fuse
Sometimes, when a wire breaks in a circuit or a connection is faulty, a leak of electric
current is likely to occur. Since an electrical current produces heat, such a leak may be
very dangerous and may cause a fire. A break of this kind is known as a short-circuit. To
avoid such kind of accidents we insert a fuse in the circuit. Sometimes, due to sudden
increase of voltage supply electric appliances get damaged. A fuse inserted in a circuit
also saves electric appliances during such situation. The fuse is a piece of wire made of a
metal wire having very low melting point. It is generally encased in a porcelain cover that
is fixed into the fuse box.
4. Magnetic effect of electric current
A great Scientist Hans Christian Oersted noticed that a needle gets deflected when an
electric current is passed through a wire placed near it. It made him realize that electric
current has a magnetic effect.
When a piece of iron is wound by wire and an electric current is passed through the wire it
behaves like a magnet, but, when the current is switched off it loses its magnetism. This setup
is called an electromagnet.
5. Uses of electromagnets
Electromagnets are used in various electrical equipments, appliances and machines,etc.
Electromagnet is used in generators, motors, mixer grinders,
v
washing machines, etc.
In these electrical appliances electromagnet is used to rotate the rotor fitted inside
the machines.
v
Electromagnets attached to cranes are used to lift huge loads of metals.
Electromagnets are used in telegraphs, telephones, loudspeakers, electric
bells, etc.
v
Electromagnets are also used to separate magnetic substances like iron, nickel,
cobalt from non-magnetic substances like copper, zinc, brass, etc.
6. An electromagnet is made by winding enamelled copper wire around a soft-iron core
(insulated). When an electric current is passed through the windings, the soft iron
behaves like a strong magnet. But when electric current is switched off, it loses its
magnetic effect.
7. Construction
An electric bell consists of a horse shoe shaped electromagnet. It is connected with an
armature with its one end. The armature is connected with a contact screw and the one
end of this contact screw is the switch. The other end of the armature is connected with a
hammer. A gong is fixed just near the hammer.
Working
When we push the button of electric bell, electric current begins to flow through the
electromagnet. As a result, it attracts the iron bar (armature) towards itself causing the
hammer to strike the gong. When it happens, the contact between the armature and the
screw breaks and the circuit converts into an open circuit, and the current flow stops. In
this way the electromagnet loses its magnetism and the armature returns to its place to
complete the circuit. As soon as it returns to its place the current again starts to flow and
the entire cycle of events is repeated.
B. HOTS
1. In a circuit containing electric cell fuse is not required as the amount of current is low.
2. Copper wire has a high melting point. Therefore it cannot be used as fuse wire.
3. The effect of electric current takes place only when the circuit is completed. The bird is
not harmed because it does not form a complete circuit.
4. Tungsten offers a great resistance to electric current and has a high melting point .
Therefore it is used in a bulb.
CHAPTER 14
Test Yourself, Page No. 145
1. Forests help to maintain hydrological cycle, ratio of oxygen, carbon dioxide and water
table. These prevent soil erosion and provide many products.
2. Different components of forests are producers, consumers and decomposers.
3. Food chain is a sequence of living organisms in which one organism
eats another. e.g. Green plant- grasshopper- frog- snake- eagle.
4. Plants depend on animals for CO2, pollination, dispersal and decomposition process.
Test Yourself, Page No. 146
1. Depending upon the life span trees are classified as Annuals, Biennials and Perennials.
2. Crown is the branchy part of a tree above the stem.
3. Canopy is the top most layer of the crown of tall trees.
4. Trees hold the rain water and reduce its speed preventing floods.
5. Forest Conservation
There are different ways by which we can conserve forests. Few of them are listed below:
(i) Harvesting should be planned. Some of the trees of the forest should be cut at a
time so that forest cover is maintained.
(ii) A forest can be renewed by planting, seedlings or small trees during the rainy
season .Van Mahotsava should be observed by planting seedlings in large
numbers.
(iii) Overgrazing by animals in the forests should be stopped.
(iv) Forest fires must be checked. Most of the forest fires are caused due to carelessness
of the people in that area. Smoking or cooking in the forest area should be avoided.
(v) Forests must be protected from insect and pests. Insecticides
and pesticides should be used to control insects and pests. The infected trees of the
forest should be removed or treated with suitable insecticide or pesticide.
Formative Assessment ,Page No. 146
A. 1. (d) 2. (c) 3. (a) 4. (b) 5. (c).
B. 1.
Environment 2. Destruction 3. Recycling 4. Deforestation.
C. 1.
T 2. F 3. T 4. F 5. T.
D. 1.
Deforestation refers to cutting down of trees on large scale.
2. Bamboo, paper, pulp, latex.
3. Habitat is the living place of an organism.
4. Silviculture, Van Mahotsava.
5. Plants – deer – lion.
6. Forests prevent soil erosion thereby main training the quality of soil.
7. Wide variety of animals have been vanished due to deforestation.
Summative Assessment, Page No. 148
A. 1. (i)
Forests are the habitat of a large number of animals,birds, reptiles etc. and they are
reserve of biodiversity.
(ii) Forests help to maintain hydrological cycle. These improve the moisture content
of the atmosphere resulting in rainfall.
(iii) Forest also help to maintain the ratio of oxygen and carbon
dioxide in the atmosphere so that clean air can be provided.
2.
The four main causes of deforestation are 1.
large scale catting of
trees by humans. 2. Forest fires 3. Overgrazing by animals and
clearing forest for growing crops.
3.
Forests maintain balance in environment by checking the ratio of
oxygen and carbon dioxise in the atmosphere.
4.
Forests regular a large number of food chains by creating.
5.
Afforestation is regenerating lost forest area by planting more trees.
6.
Deforestation is cutting of trees on a large scale or destroying forests to clear land
for human use.
B. HOTS
1.
2.
3
4.
A. 1.
B. 1.
C. 1.
2.
3.
4.
5.
D. 1.
2.
3.
4.
5.
If plants disappear from the earth, there will be no life on the earth.
To prevent noise and air pollution.
Forests purify the air and maintain oxygen and carbon dioxide ratio. Therefore they are
called nature's lungs.
Clearing of trees will result in increase of carbon dioxide in the air resulting in global
warming.
Practice Paper for Formative Assessment-III
Based on Chapter 11 to 14
Plasma 2. Roots 3. Energy 4. Canopy 5. moving.
F 2. T 3. F 4. T 5. T.
Left ventricle pumps oxygenated blood to all the parts of the body.
To overcome unfavorable conditions.
Water helps the enzymes inside the seed to be active, they digest the stored food and
make it soluble.
Forests act as a barrier for fast moving water which can result in flood.
Stomala are the openings on the under side of the leaves.
Composition of blood
It is composed of a fluid portion plasma (50-55% of the volume) and three types of
corpuscles (45-50% of the blood volume) namely RBC , WBC and blood platelets.
Pollination
The pollen grains are carried from the anther to the stigma. This process is called
pollination. Pollination cannot take place by itself. So, this job is done by insects like
bees and butterflies or wind. They carry male cells (gamete) to the female egg (stigma).
The stigma produces a liquid with sugar in it. It lets the male cells move down the tube
called style to reach the ovary which has ovules in it. These ovules have female cells in
them. Thus the fusion of the male and female cells causes the flower to be fertilized and
an embryo (zygote) to develop.
Working of an electric bulb
An electric bulb consists of a coiled filament made up of tungsten. An inert gas is also
filled in the glass to avoid any chemical reaction with heat. Tungsten is used because it
offers a great resistance to electric current and it also has high melting point. Some time
Nichrome is also used. That is why, when electric current is passed through it, it starts
glowing but does not melt.
Forests maintain balance in the ratio of oxygen and carbon dioxide:
(i) Forests maintain hydrological cycle.
(ii) Forests maintain biodiversity.
(iii) Forest prevent soil erosion and floods.
Pulse Rate
The number of pulse beats per minute is called the pulse rate. Pulse rate indicates the
number of heart beat when the ventricles. contract and when the ventricles relax.
E. 1.
Human xcretory System
F.
1. (c) 2. (d) 3. (a) 4. (b) 5. (a).
CHAPTER 15
Test Yourself, Page No. 153
1. Water is useful to us in our day to day life. We use it for drinking, bathing, cleaning,
washing, cooking, gardening and producing electricity etc.
2. Water is required by the plants to make their food and for the germination of seeds.
3. Water table refers to the upper limit of the soil where all the pores in the soil and gaps
between the rocks are filled with water.
The water found below the water table is ground water.
Factors responsible for ground water depletion are unlimited agricultural use,
industrialisation, increased population, poor rainfall, deforestation and construction
activities.
6. Ground water stored between the layers of hard rocks below the water
table form aquifer. These are recharged by rain water seeping into the soil.
7.
Water helps in economic development because it is used in industries like thermal power
plants and hydroelectric plants.
Test Yourself, Page No. 155
1. Circulation of water in the nature is called water cycle.
2. Basic steps for the management of water are:
(i) Preventing the wastage of water at each level.
(ii) Recharging the ground water.
(iii) Use of modern methods.
3. Drip irrigation is a technique by which water is directly delivered at the base of the plant
in the forms of drop.
4.
Bawris is a traditional way of collecting water. It is also called step well.
We can conserve water in the following ways:
5.
(i) Turn off the tap when you do not need water.
(ii) Instead of taking a shower bath use buckets and mugs.
(iii) Do not wash vehicles with running water. Use buckets and wet cloth.
(iv) Rain water harvesting should be encouraged to recharge ground water.
(v) Dams should be constructed along the rivers to control floods.
(vi) Water pollution should be controlled.
(vii) Stop the floor instead of washing with running water.
(viii) Clean the car with a wet cloth or sponge instead of washing it.
(ix) Drip irrigation technique of watering plants can be adapted in less rainfall area.
(x) Bawris to be revived.
6. If plants will not get sufficient water there will be:
(i)
Less rainfall.
(ii) No food from plants.
(iii) Decrease in the percentage of oxygen in the atmosphere.
(iv) Increase in the percentage of carbon dioxide.
Formative Assessment, Page No. 156
A. 1.
(c) 2. (b) 3. (c) 4. (c) 5. (c).
B. 1.
Water table 2. Temperature 3. Water 4. Force of steam 5. Water pollution 6. Drip.
C. 1. F 2. T 3. T 4. F 5. F.
D. 1. Three daily uses of water are drinking, washing and cooking.
2. Three industrial uses of water are producing electricity, agriculture and thermal power
station.
3. Water helps in smooth functioning of the body processes especially in digestion and to
maintain body temperature.
4. Infiltration refers to percolation of water through the soil after a shower.
5. Different sources of water are rain, water rivers, lakes, ponds.
Summative Assessment, Page No. 157
1. Circulation of water in the nature is called water cycle. In nature water is found in three
forms solid, liquid and gas. All these forms keep changing in nature by the processes like
evaporation, condensation, and precipitation and create water cycle. For this water
evaporates from water bodies like ponds, lakes, rivers etc. And reach the atmosphere
where these water vapoure cool resulting in condensation. Condensation change the
water in cloud form to rain which is called precipitation.
2. Water and Economic Development
Water is one of the most important natural resources.
(i) It is necessary not only for the survival of the plants and animals, but also for
agricultural as well as industrial development
4.
5.
3.
4.
5.
6.
(ii) Agricultural production depends on the availability of water. However different
agricultural crops need different amounts of water. Wheat crops need
comparatively less amounts of water than the rice crops. But, no plant or crop can
be grown in the region if there is no water. In the great Himalayan Desert or Thar
Desert a few vegetation are found because these parts of the earth have very little
water.
(iii) Water is also used in industries on a large scale to produce goods as well as
electricity.
(iv) Specially in textile industry and paper industry water is used on a large scale.
(v) Water is needed both in thermal power plants and hydroelectric plants.
(vi) In thermal power plants water is converted into steam and the force of steam is
used to rotate the turbines. But in hydroelectric plants, the force of moving water is
used to rotate the turbines. Thus water is one of the most important
natural resources which is essential for economic development of a country.
Conservation of water
(i) Turn off the tap when you do not need water.
(ii) Instead of taking a shower bath use buckets and mugs.
(iii) Do not wash vehicles with running water. Use buckets and wet cloth.
(iv) Rain water harvesting should be encouraged to recharge ground water.
(v) Dams should be constructed along the rivers to control floods.
Factors that affect the water table
(i) Unlimited agricultural use.
(ii) Excessive use by human beings due to increasing population.
(iii) Industrialisation.
(iv) Poor rainfall.
(v) Deforestation.
(vi) Construction activities.
The gradual and continuous lowering of water table is called ground water
depletion.
Rain Water Harvesting
Rain water harvesting is a technique to recharge ground water. Most of the rain water in
towns and cities is not utilized in any way. This water generally goes out of towns and
cities through drains. In this technique rain water is collected in a low lying land or
aitches through pipes connected to the roofs of the house. The collected water is
gradually seeped into the earth and ground water is charged. In many States
installation of rain water harvesting system has been made a necessary
condition in large houses and high rise buildings.
Water Management
Water is a natural, renewable resource, required by every living organisms. Water is
supplied to people of different area through different means. In cities water is provided
by civic authorities through pipes. In smaller towns, underground water is pumped out
and supplied to people. Beside wells tube wells are also used by them. As the water is
required for the survival of all living organicism. It is necessary to manage it so that its
available for a longer time.
B. HOTS
1.
Our population is more and hence demands have increased so we need to conserve
more water.
2. We get fruit juice from fruits.
3. Deserts have scarcity of water therefore there is few vegetation.
4. We can save water by using it wisely and judiciously.
CHAPTER 16
Test Yourself, Page No. 162
1. In developed cities drains are constructed under the ground. These are called
sewer.
2. Small cities have open drainage system to dispose of liquid waste.
3. Eutrophication leads to excessive growth of algae that consume a large part
of oxygen from water which is harmful for aquatic life.
Sewage treatment help to get ride of problems like shortage of drinking water
and disposal of waste.
5. Pathogens are removed from the sewage waste by tertiary treatment. It
involves passing of water through clear quartz tubes exposed to intense ultra
violet light.
Formative Assessment, Page No. 162
A. 1.
(d) 2. (c) 3. (a) 4.(d).
B. 1.
Eutrophic 2. Contaminants 3. Eucalyptus 4. 2005-2015 5. Drainage.
C. Organic impurities – Human faeces (bio-degradable) oil (Non-bio-degradable). Inorganic
impurities – Nitrite (bio-degradable) Metal (Non- biodegradable).
D. 1.
T 2. T 3. T 4. F 5. T.
E. 1.
Waste water is dirty water or used water.
2.
Sewage is liquid or semi-liquid waste produced from household and industries.
3. Cholera, jaundice, diarrhoea, dysentry.
Summative Assessment, Page No. 163
A. 1.
(i) Open drains or sewage are the breeding ground for flies, mosquitoes and other
micro-organisms that spread diseases like cholera, jaundice, diarrhoea, dysentery,
etc.
(ii) Sometimes waste water enter the pipes of water supply and contaminates this
water. This contaminated water if consumed, can cause severe health hazards.
(iii) Waste water also percolates through the surface and reaches the ground water. In
this way many harmful organic and inorganic matters mix up with ground water
which leads to pollution of ground water. This water cannot be used for drinking
purpose.
(iv) Pollution of a lake or pond by sewage or fertilizers make it eutrophic. It means
disposal of sewage into lakes or ponds causes high concentration of nutrients in
them. This process is referred to as eutrophication. This leads to excessive growth of
algae. These algae consume a large part of dissolved oxygen which results in
depletion of O2 in water. Due to acute shortage of O2 many aquatic plants and
animals die. This water cannot be used for household purposes.
2. Sewage Treatment is done in three phases – primary treatment,
secondary treatment and tertiary treatment.
Primary Treatment
(i) Screening: First of all waste water is passed through the screens of vertical bars to
remove large solid materials like plastic bags, rags, stones, cans, polythene bags, sticks,
wood pieces etc. These objects, if not removed may damage the equipments used in
water treatment plants.
(ii) Grit Chambers:Water is then passed through settling tanks,
known asgritchambers. Here the speed of incoming waste wateris controlled
carefully so that solids such as sand, silt and gravel settle down and are removed.
(iii) Sedimentation tanks (clarifiers): After passing through grit chambers, waste
water is allowed to pass through sedimentation tanks. These are large tanks in
which organic materials settle down and are removed with a scraper.
Floating
materials like oil and grease are removed with the help of a skimmer. The water now
obtained from sedimentation tank is called clarified water.
(iv) Digesters: The sludge collected is sent to separate tanks called digesters, where
it is broken down by anaerobic bacteria. Dried sludge can be used as a fertilizer.
The biogas (methane) formed can be used as a fuel.
Secondary Treatment
Aeration tank:The next step – involves passing the clarified water
into the aeration tank. Aerobic bacteria present in the aeration tank growrapidly
andconsume organic contaminants like faces food waste,detergents and convert it
into carbon dioxide.This takes several hours. The bacteria ultimately settle down at
the bottom as activated sludge and the water is removed from the stop. The dried
4.
sludge is used as manure.
Main steps used in sewage treatment are:
Primary Treatment – (i) Screening (ii) Grit chamber
(iii) Sedimentation tanks (iv) Digesters.
Secondary Treatment– (i) Aeration tank (ii) Tertiary treatment.
4.
It is necessary to treat sewage before disposing it of in a water body, because it can create
environmental problem. For example
(i) Used oil or ghee forms a thick layer inside the sewer and block the pipes. It also
reduces water absorbing capacity of the soil resulting in reduced seepage of water.
(ii) Chemicals like paints, medicines motor oil etc. kill useful microbe.
(iii) Solid waste like tea leaves, left over waste etc. slow down the degradation process.
B. HOTS
1. Those used for sewage disposal.
2. Plastic is non- bio degradable. If eaten up by animals it can kill them. It can also block the
drainage system.
3. Waste water treatment plant.
4. Human excreta is used for producing biogas.
CHAPTER 17
Test Yourself, Page No. 167
1.
Ancient people used to get a rough idea about time from some natural events like
sunrise, sunset etc.
2. Sundial works on the principle that there is change in length of a shadow with change in
position of the Sun.
3. Dutch Scientist Huggins invented pendulum in 1656.
4. Three modern time measurement devices are pendulum, quartz clock, digital clock.
5. There are 86400 seconds in one day.
6. Stop watches are used to know the time taken in completing a certain piece of work.
These can read time upto one-tenth of a second.
7. Wrist watch is based on the working of pendulum clocks.
Test Yourself, Page No. 170
1. When an object moves with a constant speed and cover equal distance in equal intervals
of time, we say that this motion is uniform. Look at the following table which displays the
distance covered by a car in given intervals of time.
Time
Time Taken
Total Distance
Distance cover in equal interval
equal interval
1:00
0
1:05 pm
5 Minutes
5 km
5-0 =5 km
1:10pm
5 Minutes
10 km
10- 5 =5 km
1:15pm
5 Minutes
15 km
15-10=5km
1:20pm
5 Minutes
20 m
20- 15= 5km
1:25 pm
5 Minutes
25 km
25- 20= 5km
3.
Y
25
(Distance in km)
20
15
10
5
0
1:05
1:10
1:15
1:20
1:25 X
Time
2.
The above mentioned graph clearly shows that the car is covering equal distances in
equal intervals of time i.e. 5 minute.
It means the car is in uniform motion.
Devices used to measure distance and speed are odometer and speedometers
respectively.
Formative Assessment, Page No. 171
A. 1. (c) 2. (b) 3. (d) 4. (c) 5. (a)
B. 1. Maharaja Jai Singh 2. Huggins 3. Digital 4. Position 5. Speed.
C. 1. (e) 2. (a) 3. (f) 4. (c) 5. (d) 6. (b).
D. 1. Sundial is a set up which tells time on the basis of movement of Sun
and formation of shadow.
2. 1. Digital 2. quartz 3. stopwatch.
3. We use stop watch to nte time of a particular event.
4. If an object does not change its position it is said to be at rest.
5. Speed refers to distance covered by object per unit time.
6. When an object covers equal distance in equal intervals of time.
The motion is said to be uniform motion.
Summative Assessment, Page No. 172
A. 1. Sand clock is an important device used to measure time in ancient time. It is also
known as hour glass. It is based on the principle that a certain quantity of sand falls
from the upper chamber into the lower chamber in one hour.
2. A pendulum consists of a weight tied to a string at the lower end.
The upper end of the string is attached to a support. On giving a
little push the pendulum makes to and fro movements about its position. The length
and weight of the pendulum is taken in such a way that it takes one second for one
to and fro movement. The needle of the minute is set in such a way that it moves
one step further in 60 seconds and the needle of the hour moves one step further
when the needle of minute completes one full rotation. The to and fro motion of a
pendulum is known as oscillatory motion.
3. These clocks work on the basis of the vibration of certain crystals of a substance. These
crystals are also called quartz and the watch in which these quartz are used are called
quartz watches. These watches and
clocks are widely in use. They can give time in fraction of a second, because the quartz
used in such watches vibrates very fast and with a very precise rate.
4. Difference between Rest and Motion
Motion
1. When an object changes its position with
respect to the observer it is said to be in
motion.
2. For example people sitting in a train
which is moving are said to be in
motion.
Rest
1. When an object does not change its
position with time and with respect to the
observer. It is said to be at rest.
2. For example people standing on a
platform are said to be at rest.
5.
Difference between Uniform and Non-Uniform motion
Uniform Motion
Non-Uniform Motion
1. When an object moves with a constant speed 1. When an object covers unequal distance
and covers equal distance in equal intervals to
in equal intervals of time, we say this
time, we say this motion is uniform motion.
motion as non-uniform motion.
2. Graph for uniform motion.
2. Graph for non-uniform motion.
Y
25
Y
25
20
(Distance in km)
(Distance in km)
20
15
15
10
5
10
0
5
0
1:05
1:10
Time
1:05
1:10
1:15
1:15
1:20
1:25 X
1:20 1:25 X
Time
B.
HOTS
1. Speed of 60 km/hr means the driver covers 60 km in one hour.
This speed in mt/sec is
100 m
60000 m
1 km= 1000 mt
=
60 km / hr =
3600 sec.
6 sec.
60 km×1000
1 hour= 3600 sec
= 16.6 m / sec.
2.
60 km= 60,000 mt
1 hour = 3600 sec.
For measuring time, many devices are available which measure the smallest number
also.
Distance
3.
Time
Lesson 18
Test Yourself, Page No. 177)
1. Objects which have their own light are called luminous objects.
2. A thick ray of light is called beam of light.
3. Different kinds of beam of light are Parallel beam of light, convergent beam of light,
Divergent beam of light.
4. Take three pieces of card-board of the same size. Placing them one upon the other, make
a hole in all the three pieces with something sharp and pointed. Now mount the cardboard pieces on similar stands of equal height and place them on a smooth table in
upright positions such that their holes are in the same straight line. Now light a candle
and place it such that its flame is just before the hole of the card-board piece at one end.
Look through the holes from the other end. The flame of the candle shall be visible. It is
because the light travels in straight line. Now move the middle card-board a little to one
side and again look at the flame of the candle. The flame will not be visible because the
holes are not in the same straight line now. If you place the middle card-board in its
position once again, the flame shall be visible again.
5. Two kinds of reflection are regular reflection and irregular reflection.
Test Yourself, Page No. 181
1. Lateral inversion is a phenomenon in which left hand side of an object appears as right
hand side and vice versa.
2. Different kinds of mirror are plane mirrors and spherical mirrors.
3.
Concave mirror
Convex mirror
(a) Concave mirror has its surface (a) Convex mirror has its surface curved
curved inwards like the inner surface of a outwards like the outer surface of the
sphere.
sphere.
(b) Image formed by concave mirror is (b) Image formed by convex mirror is
erect, uneral enlarged.
virtual, erect, diminished.
4.
5.
Image formed by convex mirror is virtual, erect and diminished.
Concave mirror is used for shaving and in headlights of automobiles, solar cookers, by
dentist to see back the tooth in telescope, microscope and in make up mirrors.
Test Yourself, Page No. 183
1. Focal length of a lens is the distance between the optical centre and the focus of a lens.
2. Difference between convex lens and concave lens.
1.
2.
3.
3.
Convex lens
It is thicker in the middle and
thinner at the edges.
It is a converging lens.
It forms real and inverted image
except when an object is placed very close
to the lens.
Concave lens
1. It is thinner in the middle and thicker at the
edges.
2. It is a diverging lens.
3. It always form virtual, erect and smaller
images.
Two rays diagrams of convex lens
Object
F
O
image
(virtual erect)
F
Image
F Object very
near to lens
F
When the object is very close to the lens
The image is
¨
erect
¨ virtual ¨ enlarged
4. When passed through the prism white light splits into seven colours. The
order of the colours are called VIBGYOR violet, indigo, blue, green yellow,
orange and red.
5. The colour pattern, VIBGYOR, is called spectrum.
6. Diagrams of concave and convex lens.
F2
F1
O
Convex Lens
Concave Lens
Formative Assessment, Page No.184
A. 1. d
2.
c
3. a
4. a 5. c
B. 1.
Shadow 2. luminous objects 3. straight line 4. laterally 5.convex 6. pole.
C.
Column I
Column II
(i) Luminous body
(a) Motor vehicle
(ii) Natural source of light
(b) Smooth surface
(iii) Regular reflection
(c) Electric bulb
(iv) Convex mirror
(d) Dentist
(v) Concave mirror
(e) Star
D.
E.
1.
1.
2.
3.
4.
5.
6.
7.
7.
8.
9.
A.
1.
2.
T 2. F 3. T 4. T 5. T.
Three artificial sources of light are candle, bulb, torch.
Objects that give out light are called luminous bodies.
A number of light rays together form a beam of light.
Reflection of light is the process of rebounding of a light ray after striking a surface.
Centre of curvature is the centre of sphere of which the spherical mirror is a part. It is
denoted by point C.
Lateral inversion shows left hand in right and right hand in left.
A convex mirror has its surface curved outwards.
Convex lens is converging lens which is thicker in the middle and thinner at the edges.
Three properties of real images are:
(a) It is obtained on the screen. (b) It is always inverted.
(c) It is formed on the same side of the mirror.
Radius of curvature is the radius of the sphere of which the spherical mirror is a part.
Natural source of light
(i) These have their own natural
light
(ii) E.g. Sun and stars.
Artificial source of light
(i) These do not have light of their
own.
(ii) E.g. Bulb, torch etc.
Light always travels in a straight line and the following activity process it.
Take three pieces of card-board of the same size. Placing them one upon the other, make
a hole in all the three pieces with something sharp and pointed. Now mount the cardboard pieces on similar stands of equal height and place them on a smooth table in
upright positions such that their holes are in the same straight line. Now light a candle
and place it such that its flame is just before the hole
of the card-board piece at one
end. Look through the holes from the other end. The flame of the candle shall be visible.
It is because the light travels in straight line. Now move the middle card-board a little to
one side and again look at the flame of the candle. The flame will not be visible because
the holes are not in the same straight line now. If you place the middle card-board in its
position once again, the flame shall be visible again. So it s a proved that the light travels
in straight line.
3.
4.
5.
6.
7.
8.
Distance = 750,000 km.
Speed of light = 3× 108 m/sec.
Distance = 750,000,000m.
Time taken will be 7.5×108m
3×108m
= 2.5 sec.
Two laws of reflection
1. The normal, the incident ray and the reflected ray all are in the same plane.
2. The angle of incidence is equal to the angle of reflection Ði = Ðr
AMBULANCE is written laterally inverted so that it appears correct in the rear view
mirror of the vehicle moving ahead. It is based on the phenomenon of lateral inversion
according to which left hand side of an object appears as right hand side and vive versa.
Uses of convex mirrors
1. Convex mirrors are used in the automobiles to see rear view. It forms small erect and
diminished image close to the eyes of the driver.
2. Convex mirrors are used as street light reflector as they diverge the rays of light.
3. These are used as distance view mirrors at a turning points of narrow stair case.
4. These are used in big shops and warehouse for vigilance.
Convex lens is a magnifying glass and the other can be termed as a concave lens.
Ray diagrams for the image formed by the concave lens
A concave lens always produces a virtual, erect and diminished image lying very
close to the lens.
(i) When the object is nearer to the lens
Object
F Image
Image: Virtual and Smaller
(ii) When the object is far off from the lens.
Rays coming
from a far off
object,
(say the sun)
Image
F
Image: Erect Virtual and Very small
B. HOTS
1. It will look slightly pinkish on rotating.
2. Convex lens is thicker in the middle and thinner in the edges while concave is thinner in
the middle and thicker at the edges. A convex lens has both the surfaces bulging out
where as a concave lens is opposite of it.
CHAPTER 19
Test Yourself, Page No. 189
1. The different layer of atmosphere are:
(a) Troposphere (b) Stratosphere (c) Mesosphere (d) Thermosphere.
2. Wind is the moving air.
3. Air pressure helps us in daily life as follows:
(a) In drinking a liquid through a hollow straw.
(b) In driving a bicycle.
(c) To row the boat etc.
4. Air Expands on Heating
All the three states of matter solids, liquids and gases expand on heating. But gases
expand more, as compared to solids and liquids. As air is a mixture of gases, it also
expands of heating. Example from our daily life making of Chapatties.
5. Land gets heated up faster.
Test Yourself, Page No. 191
1. Thunderstorm is a storm resulting from strong rising air currents heavy rain or hail.
2. Precautions which must taken during a thunderstorm
All the thunderstorms are dangerous Lightning that occurs with thunderstorms cannot
only damage building, but can also kill people and destroy plants. So we must take the
following precautions during a thunderstorm.
3. A cyclone is a small low pressure system with very high speed winds revolving around it.
4. Factors that contribute to the formation of a cyclone are wind speed, wind direction,
temperature and humidity.
5. Tornadoes are the storms which form very suddenly on he land. The highest wind
peeds on the earth occur in tornados. In fact a torando is a dark funnel shaped cloud
that reaches from the sky to the ground. Most of the tornados are weak.
Tornados are not very frequent in our country.
6. CDR stands for Cyclone Detection Radars.
7. DWS is Disaster Warning System.
Formative Assessment, Page No. 192
A. 1.
(b) 2. (c) 3. (c) 4. (a) 5. (a).
B. 1.
Gases 2. Moving 3. Lighter, Cold air 4. A metal sheet 5. USA.
C. 1.
F 2. T 3. F 4. T 5. T.
D. 1.
Wind is moving air.
2. Factors that affect the speed and direction of the wind are:
(a) Location of the earth (b) Rotation of the earth (c) Local conditions (d) Height from
the ground.
3. The air pressure is used in our daily life. The air pressure is caused due to the constant
pressure by moving air molecules on the surface of the body. In fact the pressure of
atmosphere at ground level is very hung and damage the body.
4. Smoke coming out from industries prove that air expands on heating.
5. Smoke rises up. It proves that air expands on heating.
6. Thunder storm is a storm resulting from strong rising air currents, heavy rain or hail.
7. Thunderstorm develops in hot, humid, tropical areas.
8. Monsoon winds are cooler and denser winds which carry lot of water and move from the
oceans towards land.
Summative Assessment, Page No. 193
A. 1.
To show that the air exerts pressure.
Fill half of the cane with water and boil it for few minutes. Cover the cane with lid tightly
and remove it from the burner. Be careful while putting the lid and removing it from the
burner. Now put the cane carefully in a washbasin or any shallow metallic vessel. Pour
fresh water over the cane. You will observe that shape of the cane gets distorted. It is
because when the water in the cane is boiled, steam pushes the air out and the space in
the can is filled with steam. On cooling the steam gets condensed to water and the
pressure inside gets lowered and the cane gets deformed under the action of higher
pressure outside. It proves that air exerts pressure. (We experience air pressure in our
daily life also).
2. To show that High Speed Winds accompany reduced air pressure.
Take two balloons of equal size and inflate them: Suspend both the balloons to a rod.
Blow air in between the two balloons and observe. You will observe that the balloons
move closer to each other. It is because when air is blown between the two balloons, the
air pressure get reduced and the higher pressure on the either side pushes the two
balloons closer.
3.
Wind Currents are Generated due to Uneven Heating on the Earth Land and
Water.
Different parts of the earth receive different amount of heat. The equator receives direct
rays from the Sun. Air gets heated and rises up leaving low pressure areas behind it.
As a result of low pressure the cooler air moves into take the place of warm air. These
winds blow from either sides north or south towards the equator. Same thing happens at
poles also. Warm air rises up from latitudes and cooler air this from the sets polar region
takes its place. This sets up circulation of wind from the polar region to the latitudes.
During summer the land near the equator becomes warm faster than the water in the
ocean. The air above the land becomes very hot and rises up. Cooler and denser winds
from the oceans flow towards the land and carry a lot of moisture. These are called
monsoon winds. In winters, the direction of the wind gets reversed. It flows from land to
90°
ocean.
60°
Polar front, warmer air
rises, low pressure
30°
Air descends, high pressure
0°
Warm air rises, low
pressure
Air descends, high pressure
30°
60°
Polar front, warmer air rises,
low pressure
90°
Earth showing different winds
4. Thunderstorms
A thunderstorm is a storm resulting from strong rising air currents, heavy rain or hail. It is
accompanied with lightening and thunder. For the formation of a thunderstorms
moisture, front and rapidly rising warm air is required.
Thunderstorms develop in hot, humid, tropical areas like India very frequently.
Thunderstorm
Due to the heat of the Sun the temperature of a place increases. The increased
temperature warm up the air which create strong winds rising in upward direction. These
winds also carry water droplets which finally freeze and fall back on the earth. This
movement of warm air in upward direction and falling droplets of water creates lightning
and sound.
5. Effective safety measures against cyclones, to prevent cyclone disasters
(a) By the Government:
1. Cyclone forecast and warning system must be installed.
2. Construction of storm shelters.
3. Rapid communication system to inform people about the cyclone well in time.
4. Planting of trees in large scale.
5. Generating public awareness about the measures that can be taken by the people
to avoid damage caused due to cyclones.
(b) By the people in a cyclone hit area.
1. Follow the guidelines provided by the agencies through TV, Radios, phones etc.
2. Shift your essential household goods, domestic animals etc. to safer places.
3. Do not touch electrical wire, switch etc.
4. Keep all the emergency phone numbers like phone number of hospitals, fire
brigade, police etc. ready.
5. Do not move on the roads which are covered by water (due to flood).
6. Do not drink water from local sources it might be contaminated.
7. Do not go out just for fun sake.
8. Do not pressurise the reserve force by making undue demands.
9. Co-operate with your neighbours and help them.
10. After the cyclone check gas leakages and dry the electrical appliances.
6. Advanced Technology for Cyclone Forecasting and Warning
The Indian Meteorological Department studies inform about the development and
movement of cyclones. This is done with the help of INSAT Satellite and chain of
cyclone Detection Radars (CDRs) installed along the coastal belt of India. These radars
can locate and track an approaching cyclone within a range of 400 km.
Disaster Warning System (DWS) issue a cyclone alert 48 hours in advance and cyclone
warning 24 hours in advance. These messages are transmitted quickly and widely for
general public fisherman, farmers and different categories of users such as central and
State Government Officials responsible for disaster mitigation and relief, industrial and
other establishments located in the coastal areas, railways, aviation, communications
and power authorities.
B. HOTS
1. Holes are made in banners to prevent the damage caused by high speed wind.
2. We would like to have windows and ventilation on to maintain proper temperature
conditions.
3. Warm air expands and therefore occupies more space. As a result of which its density
decreases making it lighter.
Practice Paper for Formative Assessment - IV
Based on Chapter 15 to 19
Page No. 194
A. 1. Absorption 2. steam 3. disaster warning system (DWS) 4. One 5. laterally.
B. 1. F 2. F 3. F 4. T 5. F.
C. 1. (d) 2. ((e) 3. (a) 4. (b) 5. (c).
D. 1. (d) 2. (b) 3. (a) 4. (a) 5. (a).
E. 1. Water and economic development
Water is one of the most important natural resources.
(i) It is necessary not only for the survival of the plants and animals,
but also for agricultural as well as industrial development. (ii)
Agricultural
production depends on the availability of water. owever different agricultural
crops need different amounts of water. Wheat crops need comparatively less
amounts of water than the rice crops. But, no plant or crop can be grown in theregion if
there is no water. In the great. Himalayan Desert or That Desert a few vegetation
are found because these parts of the earth have very little water. (iii)Water is also used in
industries on a large scale to produce goods as well as electricity.
(iv) Specially in textile industry and paper industry water is used on a large scale.
(v) Water is needed both in thermal power plants and hydroelectric plants. In
hermal power plants water is converted into steam and the force of steam is
used to rotate the turbines. But in hydroelectric plants, the force of moving water
is used to rotate the turbines. Thus water is one of the most important natural
resources which is essential for economic development of a country.
2. Distance = 6 km
= 6000 m
Time = 1 hour
= 60 min
Speed in metre/ minute
100
=6000
60
= 100 metre/minute
distance travelled in 15 minutes = 100×15 = 1500 m=1.5 km.
3. Two Laws of Reflection
After understanding the terms regarding reflection we can easily follow the two laws of
reflection which are as under :
(i) The normal, the incident ray and the reflected ray all are in the same plane.
(ii) The angle of incidence is equal to the angle of reflection.
(Ð i = Ð r)
4.
Cyclones are dangerous Cyclones are very destructive:
(i) Cyclones are accompanied by very strong winds which can uproot trees, electric
poles damage.
telephone system, buildings and house, killing many people.
(ii)
F.
Cyclones may also cause heavy rain for a prolonged
period. It may lead to floods causing loss of life and property and water borne
diseases like typhoid etc.
(iii) Cyclones can cause loss of soil fertility.
(iv) The low pressure in the eye of the cyclone lifts water to a height of up to 12m.This
water enters low lying coastal areas and cause severe loss of life and property.
(v) Even after the cyclone is over, rail system, road system, transport system may
remain blocked and can cause inconvenience.
5. Precautions which must taken during a thunderstorm
All the thunderstorms are dangerous Lightning that occurs with thunderstorms can not
only damage building, but can also kill people and destroy plants. So we must take the
following precautions during a thunderstorm.
When you are outside
(i) Do not use an umbrella with a metallic handle.
(ii) Do not stand under an isolated tree. If you are in a forest take shelter under a small
tree.
To find out the focus in a convex lens. Let us take a convex lens and a white paper. Let sun rays
fall on it, placing the paper below the other side of the lense. Distance between the lens and
paper adjusted so that the rays converge at one point making the bright spot on paper. If
we keep it for few minutes, the paper may start burning. Actually this is the image of the sun
formed on paper by the convex lens.
G.
S P E E D
S
A
V
A
N
4A
D
P
Q
C
O
R
L
U
5 C O N T A M I N A N T 6S
F
E
C
T
K
I
E
W
R
O
E
R
N
H.
1.
A.
1.
2.
3.
4.
5.
B.
1.
2.
3.
Rain Water Harvesting
Rain water harvesting is a technique to recharge ground water. Most of the rain water in
towns and
cities is not utilized in any way. This water generally goes out of towns and cities through
drains. In this technique rain water is collected in a low lying land or ditches through
pipes connected to the roofs of the house.
The collected water is gradually seeped into the earth and ground water is charged. In
many States installation of rain water harvesting system has been made a necessary
condition in large houses and high rise buildings.
Practice Paper for Summative Assessment-II
Based on Chapter 11 to 19
Dispersal of seeds is a natural phenomenon that helps in scattering of seeds over a large
area.
Different food chains are connected to each other and form a web that is known as food
web.
A tornado is a dark funnel - shaped cloud that comes down from high above and cause
extremely high speed winds.
When sunrays fall on a convex lens, they converge on the other side of lens of a point on
the principal axis, this point is called principal focus.
A break of any kind that arises out of producing of heat in a circuit is known as short
circuit.
Electromagnets are used in call bells and telephones.
We can conserve forests by not cutting them and planting more trees.
(i) Hour Glass. It is based on the principle of sand falling from upper chamber into the
lower chamber in one hour.
5.
6.
C.
1.
2.
3.
4.
5.
D.
1.
(ii) Digital clocks: The most advanced time measuring devices that display time in
digits.
Because in a convex mirror, light coming from infinity converges at the focus, so the
driver can see the vehicles that are behind him.
Heart pumps blood to all parts of the body and is a muscular organ that lies between
lungs.
Advanced technology for cyclone forecasting and warning
The Indian Meteorological Department studies inform about the development and
movement of cyclones. This is done with the help of INSAT Satellite and chain of cyclone
Detection Radars (CDRs) installed along the coastal belt of India. These radars can
locate and track an approaching cyclone within a range of 400 km.
Disaster warning system (DWS) issue a cyclone alert 48 hours in advance and cyclone
warning 24 hours in advance. These messages are transmitted quickly and widely for
general public fisherman, farmers and different categories of users such as Central and
State Government Officials responsible for disaster mitigation and relief, industrial and
other establishments located in the coastal areas, railways, aviation, communications
and power authorities.
Working of an electric bulb
An electric bulb consists of a coiled filament made up of tungsten. An inert gas is also
filled in the glass to avoid any chemical reaction with heat. Tungsten is used because it
offers a great resistance to electric current and it also has high melting point. Some time
michrome is also used. That is why, when electric current is passed through it, it starts
glowing but does not melt. We should not touch a glowing electric bulb because it is very
hot.Why do we use a coiled filament in a bulb? To shorten the length of the filament we
make a coil out of it. The more the length of the filament the more resistance will be
offered by it.
Components of Forests
A forest comprises of many components. These components can be broadly classified as
Biotic (living) components and Abiotic (non-living) components. The living components
interact with one another and with the non-living components to make up the forest.
The living components are further classified as:
v Producers (autotrophs)
v Consumers (heterotrophs)
v Decomposers.
Uses of Concave mirror
(i) Concave mirrors are used as shaving mirror.
(ii) These mirrors act as reflection and therefore are used in the headlights of
automobiles, in solar cooker etc.
Rain Water Harvesting
Rain water harvesting is a technique to recharge ground water. Most of the rain water in
towns and cities is not utilized in any way. This water generally goes out of towns and
cities through drains. In this technique rain water is collected in a low lying land or ditches
through pipes connected to the roofs of the house.
The collected water is gradually seeped into the earth and ground water is charged. In
many States installation of rain water harvesting system has been made a necessary
condition in large houses and high rise buildings.
Pollination
The pollen grains are carried from the anther to the stigma. This process is called
pollination.
Pollinating agents
The process of pollination does not occur itself. It is triggered by insects or winds. Let’s
see how.
Insects : When insects feed on the nectar of flowers. Some other insects attracted by the
colour and odour of the flowers. When they sit on the flowers the pollen grains stick to
their body. When these insects visit some other flowers the pollen grains fall in these
2.
E.
flowers which trigger pollination. The insects involved in pollination are bee, butterfly
and moth.
Wind : Wind also blows pollen grains from one flower to another. But, the wind
pollination generally occurs in the flower with small or no petals such as wheat, corn,
grasses, etc. These flowers exposes pistils to the wind and carry on the process of
pollination.
It is done in three phases – primary treatment, secondary treatment and tertiary
treatment.
Primary treatment
(i) Screening: First of all waste water is passed through the screens of vertical bars to
remove large solid materials like plastic bags, rags, stones, cans, polythene bags, sticks,
wood pieces etc.
(ii) Grit chambers: Water is then passed through settling tanks, known as grit
chambers.
(iii) Sedimentation tanks (clarifiers): After passing through grit chambers, waste
water then it is allowed to pass through sedimentation tanks.
(iv) Digesters: The sludge collected is sent to separate tanks called digesters, where it is
broken down by anaerobic bacteria. Dried sludge can be used as a fertilizer.
Secondary treatment
Aeration tank: The next step – involves passing the clarified water into the
aeration tank.
Tertiary treatment
The water is disinfected before discharging. It involves passing water through clear
quartz tubes exposed to intense ultra violet light.
1. Difference between Uniform and Non-uniform motion.
Uniform motion
Non-uniform motion
When an object moves with a
constant speed and cover equal
distances in equal intervals of time,
we say that this motion is uniform
motion.
2.
Difference between Convex and Concave lens.
Convex lens
Convex lens is a lens which is thicker in
the middle and thinner at the edges. It is
also called converging lens.
3.
F.
When an object covers unequal
distances in equal intervals of
time, the object is said to be in
non-uniform motion.
Concave lens
Concave lens is a lens which is thinner in
the middle and thicker at the edges. It is
also called diverging lens
In thermal power plants water is converted into steam and the force of steam is used to
rotate the turbines. But in hydroelectric plants, the force of moving water is used to rotate
the turbines. Thus water is one of the most important natural resources which is essential
for economic development of a country.
The given picture depicts a patient on dialysis.
During dialysis, blood from the arm is allowed to flow into the dialysing machine. This is
made up of a long cellophane tube coiled in a chamber with a dialysing solution. When
the blood passes through this machine the impure substances are separated and the pure
blood is sent to patient's body.