NEW TERMS:1. ATMOSPHERE-blanket of air surrounding the earth.
2. INHALE – to breathe in air.
3. EXHALE – to breathe out air.
4. EVAPORATION – process of changing water into
water-vapour on heating.
5. CHLORINATION- method of disinfecting water with
a small amount of chlorine gas.
6. CONDENSATION – process of changing watervapour into water on cooling.
7. PRESSURE- force applied on an object.
ANSWER THESE QUESTIONS:Q1. Define- 1.Humidity, 2.Sedimentation,
3.Decantation, 4.Distillation.
Ans1. Humidity:- The amount of water-vapour present in
the air is called Humidity.
2. Sedimentation:- The process of settling down of
insoluble impurities in water or liquid is called
Sedimentation. The insoluble impurities are called
sediments.
3.Decantation:- The process of transferring clear liquid
(after sedimentation) without disturbing the sediments
is called Decantation.
4.Distillation:- The process of purifying a liquid(water)
by boiling it and then condensing its vapour is known as
Distillation.
Sedimentation
Decantation
Distillation
2. How does water vapour form in atmosphere?
Ans2.Water vapour is formed because of evaporation of
water from the surface of water.
Q3. Why should drinking water be purified?
Ans3. The water bodies as well as rain water consists of
dissolved impurities like dirt, germs etc. which cannot be
seen through our eyes. Hence drinking water should be
purified.
Q4.How is air useful to us?
Ans4.Air is very useful to us in many ways:1. It retains heat and blocks harmful rays of the sun.
2. It prevents the meteorites from hitting the surface of
the earth.
3. Oxygen present in air supports the life.
Q5. How is stratosphere a very important layer of the
atmosphere?
Ans5. The stratosphere is the second and a very
important layer of the atmosphere as.
1. It contains ozone gas which protects the earth from
harmful rays of the sun.
2. There is no weather in this layer so many aircrafts fly in
this layer.
Q6. When a burning candle is covered with a glass, it
gets extinguished. Whydoes this happens? What does
this activity show?
Ans6.When a burning candle is covered with a glass, it
gets extinguished because the candle covered with glass
jar uses all the air (oxygen) present in the glass jar.
This activity shows that air is necessary for burning.
Q7. How can we prove that air occupies space?
EXPERIMENT:- Take some water in glass tub. Take a
transparent empty tumbler. Turn it upside down and dip
it into the container. Press the tumbler into the water.
OBSERVATION:- The tumbler does not dip in the water
because the tumbler contains air in it.
CONCLUSION:- This shows that air occupies space.
Q8. How can we prove that air has weight?
Ans8. EXPERIMENT:- Take two balloons of same size and
blow air into it. Tie them at two ends of a stick and
balance the stick. Now prick one of the balloon and let
the air escape from it.
OBSERVATION:- The stick tilts towards the air filled
balloon.
CONCLUSION:- The inflated balloon has air in it and so it
is heavy. This proves that air has weight.
Q5. Explain filtration with the help of diagram.
Ans5. The process of separating the insoluble and
suspended impurities from a liquid by using filter is called
filtration.
Experiment:- Take a circular paper and make a cone.
Place this cone in funnel. Place funnel on a beaker /
conical flask. Pour the mixture of soil and water into the
beaker through filter paper using glass rod.
Observation:- Drops of clear water will trickle down into
the beaker and collect as clear filtrate and soil particles
will be left on the filter paper.
Q7. What are the uses of distilled water?
Ans7. The uses of distilled water are
are1. Used in car batteries
2. in science labs
3. to make medicines
4. and in inverters...
NEW TERMS:1.Soil erosion : the process of wearing away of soil over a period of time.
2 Deforestation : cutting of trees in large numbers.
3. Soil conservation : prevention of loss of soil.
4. embankments : wall along a river bank.
5. afForestation : the process of growing
more trees by planting saplings.
6. Terrace farming: farming done on steps made on hills slopes.
7. Change the course: change the direction
ANSWER THESE QUESTIONS :Q1. what is meant by soil erosion ?
Ans1. The condition of wearing off or carrying away of soil by the action of water
or wind is known as soil erosion .
Q2. what is soil conservation ?
Ans2. Growing of trees on a large scale in place of cut down tress is called
afforestation.
Q3. what is meant by soil conservation?
1.
2.
3.
4.
5.
Ans3. the protection of soil from its erosion is called soil conservation.
Q4. when is ‘earth day’ celebrated every year?
Ans4. earth day is celebrated on 22nd april every year.
Q5 what do the 3 R’s stand for?
Ans5. The 3 R’s stand for reduce, reuse & recycle to protect the environment.
Q6. Why do we say that the soil is the foundation of life?
Ans6. We say that the soil is the foundation of life because it helps the plants to
grow. Plants provide food and oxygen to all living being on this planet.
Q7. How was soil formed from rocks?
Ans7. The soil was formed by the physical, chemical & biological weathering of
rocks. The sun heated the rocks, the rains cooled them & the wind blew over
them. This process continued for thousands of years resulting in break- down of
rocks into fine particles called soil.
Q8. how does water act as an agent of soil erosion?
Ans8. Floods are caused by heavy rains. The heavy rains remove the top soil of
the fields & mountains making the land unfit for cultivation. In this way water
causes soil erosion.
Q9. why do some rivers change their course?
Ans9. Some rivers change their course because of accumulation of soil that is
being carried down by the river while coming down from hills.
Q10. how is man responsible for soil erosion?
Ans10. Man cut down the trees on large scale due to which the top soil becomes
loose & is carried by wind & water. In this way man causes soil erosion.
Q11. list the ways by which soil can be conserved.
Ans11.
Soil can be conserved in many ways:By growing cover crops on plains.
By making terraces on hills.
By fencing the fields.
By afforestation.
By building embankment along river banks.
q12. What is soil? Name the different layers of soil.
a2. soil is the uppermost layer of the earth’s crust on which plants grow.
The different layers of soil are1. topsoil- rich in humus or organic matter, contains fine particles of clay sand and
also air and water.
2. Subsoil- contains rock pieces along with less organic matter.
3. Bed rock-contains large pieces of rocks with less water.
Q10. HOW DOES STEP FARMING HELP to REDUCe SOIL EROSION?
ANS10.
CUTTING the SLOPES INTO STEPS OR TErRACE helps to reduce soil
erosion. THE STEPS SLOWS DOWN THE FLOW OF WATER leaving some SOIL on
ONE STEP to another. the roots of tree also holds the soil and helps To REDUCe
SOIL EROSION.
LESSON 7
ROCKS ANS MINERALS
NEW TERMS:1. CRUDE OIL- unpurified or unrefined oil.
2. QUARTZ – hard crystalline used for making watches.
3. LUBRICATING – oil or grease used to make the things run smooth.
4. FOSSIL – remains of dead animals or plants that have hardened into
rocks.
5. FOSSIL FUEL- fuel like coal, oil and natural gases formed from the
dead and decaying parts of animals or plants buried in the soil.
6. sWAMPY – wet or marshy land.
answer these question:Q1 What are rocks made up of? How many types of rocks are
there?
Ans1. Rocks are made up of minerals. A rock may contain one
or more minerals. The type of rock depends on the quality,
quantity and arrangement of minerals in it.
There are three types of rocks. They are1. Igneous rock.
2. Sedimentary rock.
3. Metamorphic rocks.
Q2. What are minerals? Name the types of minerals with two
examples.
Ans2. Minerals are chemical substances present in the earth.
They are underground natural resources.
There are two types of minerals. They are1. Metallic minerals – eg. Iron, gold
2. Non-metallic minerals- eg. Coal, petroleum
Q3.How are igneous rocks formed?
Ans. Igneous rocks are formed by cooling and hardening of
magma and lava. The type of formation of igneous rock
depends on the size and kind of mineral the magma contains. It
also depends on the time taken for cooling of lava or magma.
Q4. How are sedimentary rocks formed?
Ans4. Wind and water take away the soil, sand and pebbles into
rivers, seas and oceans. They sink to the bottom and settle
down to form layers called sediments. These sediments get
cemented together due to continuous pressure, thus forming
sedimentary rocks
.
Q5. How are metamorphic rocks formed?
Ans5. Metamorphic rocks are formed from igneous and
sedimentary rocks .When these rocks are subjected to
immense heat and pressure the mineral content of these rocks
changes to form metamorphic rocks.
Q6. What are ores? Name any four types of ores.
Ans6.The minerals from which metals can be obtained easily
are called ores.
ORES-------------------------METALS
---------------------------------------------------1. Haematite---------- -----Iron
2. Bauxite ------------------- Aluminium.
3. Calamine------------ ----Zinc.
4. Copper pyrites---------Copper
Q7. Why are coal and petroleum important to man?
Ans7. Coal and petroleum are important to man because half of
the energy used in world comes from coal and petroleum. They
are also used as fuels.
Q8.Why is petroleum called fossil fuel?
Ans8.Petroleum is called fossil fuel because it is formed from
the dead remains of plants and animals of sea and or ocean
which got buried under the sea and due to continuous heat and
pressure changed these remains into petroleum.
Q9. How is coal formed?
Ans9. Coal is formed from the remains of huge, thick, swampy
forest which got buried deep in the earth and were covered
with sand and soil. The continuous heat and pressure for
million years turned this forest into coal.