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SCIENCE NOTES of Light Shadow and Reflections
Q1. In a completely dark room, can you see your face in a mirror? Why?
Ans: Due to absence of light In a dark room. Light is the source that illuminates our face
by reflection.
Q2. Why cannot we see upside down image of the sun?
Ans: Object like sun is in infinity whose image form point sized or highly demised.
Q3. Why shadows are black in colour?
Ans: It is because no light reaches on screen in area where shadow form. The colour of
object is colour components of light that reflect and reach our eyes.
Q4. Can you see an object through a “T” shaper pipe? If, no, Why?
Ans: No, it is because light always travel in straight path that is known as rectilinear
properties of light.
Q5. Can you see a reflected light directly? If, no Why?
Ans: No, the path of the ray of light is itself invisible but make the things visible only
when fall on our eyes.
Q6. What is the reason for the formation of shadow?
Ans: The rectilinear propagation of light .Kinds of shadow depends on the source f light.
(a)Point source of light form only dark and sharp shadow called the Umbra
(b)Extended source of light (smaller than object) form two reason a dark umbra and
another less dark region called penumbra.
(c)Extended source of light (larger than object) : The size of umbra decreases and
penumbra increases as screen move away from object and vice versa.
Q7. How can you see the thing around yourself?
Ans: We see the thing around us when light from a luminous object (like the
Sun, a torch or an electric light) falls on these objects and then travels towards our
eye after refection.
Q8.What is the reason for the formation of shadow?
Ans: The rectilinear propagation of light .Kinds of shadow depends on the
source f light.
(a)Point source of light form only dark and sharp shadow called theUmbra
(b)Extended source of light (smaller than object) form two reason a
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dark umbra and another less dark region called penumbra.
(c)Extended source of light (larger than object) : The size of umbradecreases and
penumbra increases as screen move away from object and vice versa.
Q9.How can you see the thing around yourself?
Ans: We see the thing around us when light from a luminous object (like
the Sun, a torch or an electric light) falls on these objects and then travels
towards our eye after refection.
Q10.How can you determine the length of the shadow of an object?
Ans: We cannot correctly determine the length of the shadow of an object. The
length of shadow depends on the angle at which light fall on a body and
varies at different time of day. This principal helps us to make sun dial
for calculating time.
Q11.How can you make sundial at home?
Ans: We take a pencil and place it into the whole of the empty spool of
thread.This work as simple sundial.
Making the Sundial:
1. Using the pencil, poke a hole on the side of the paper / Styrofoamcup pproximately 2 inches
below its top (rim).
2. Place the pebbles in the cup so to give it some weight and hold it upright.3. Cover the cup with
the plastic lid.
3. Put the straw through the hole on the side of the cup and its lid while letting about half an
inch of the straw stick out from the side.
4. Secure the straw to the cup by taping it down on the side.
Q12.How do you make a pinhole camera?
Ans: Take two rectangular boxes that fit into one another without leaving any
gap.
Cut open one side of each box.
Make a small hole in the larger box at the centre of the closed end opposite the side that has
been cut open.
Cut a square of side five centimetres in the smaller box in the closed end opposite the side that
has been cut open. Cover this square with tracing paper.
Finally, slide the smaller box into the larger box, ensuring that the pinhole and the tracing paper
are in line with one another, but at the opposite ends.
Slide the smaller box to adjust the focus so that you can capture the image of any object you
want.
Look through the open face of the smaller box. you can see the image of the object and inverted
on the screen.
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NOTES OF THE LIVING ORGANISM AND THEIR SURROUNDINGS
Q1. What is habitat?
Ans :- A place where living things live naturally is known as habitat (Home). For example:
(i)Aquatic habitat refers to the water where plants and animals survive like pond, river, sea (in water),
(ii) Terrestrial habitat: It refers to the land where all plants and animals survive. It includes deserts, forests and
grasslands, as well as coastal and mountain regions.
Q2.. What are the Components (Parts) of Habitat?
Ans: There are two main components of habitat:(a) Biotic Components: Living things present in a habitat are called biotic component like plants , animals and
micro organism.
(b) Abiotic Components: All the non-living things present in a habitat is called abiotic components like air water
soil rocks, sunlight and heat etc.
Q3. How biotic and abiotic components depend on each other?
Ans: Biotic and abiotic components in a habitat depend on each other for survival for example plants need sunlight and
for photo synthesis and animal need oxygen for respiration.
.Q4. Why are green plants called producers?
Ans: Because plants provide food to all animal and non- green plants
.Q5. Why are non-green plants animals are called consumers?
Ans: Because non-green plants animals are directly or indirectly eat food prepared by plants.
.Q6. How do scavengers help to clean environments?
Ans: Scavengers are those animals that feed (eat) on dead animals or plants and help tokeep environment clean.
.Q.8 Why micro organisms are called decomposers?
Ans: A very tiny living organism that cannot be seen by necked eyes is called micro organisms like bacteria and fungi.
Micro organisms feed on dead and decaying organic matter and break them into nutrients that are used by plants so they
are called decomposers.
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Q9. what is photo tropism?
Ans: Plants and animals show movements towards light is called photo tropism. Shot move towards light called positive
photo tropism and root move against light called negative photo tropism.
Q10. What we call animal that are active during night ?
Ans: Nocturnal like owl, bat, cockroach etc.
.Q11. Which bacteria help to use nitrogen fixed in soil to plants?
Ans: Rizobium
11.Q.What is adaptations?
Ans: Living organism modifies themselves according to different types of habitat called adaptations.
12. Q. Distinguish between herbivores and carnivores?
Ans: Herbivores feed on plants where as carnivores feed on flesh of other animals.
13. Q. State any two flight adaptation in aerial animals?
Ans: (i) Having streamline body shape that protect from wind
(Ii) Having hollow bones called pneumatic bones
.Q14.. How does temperature affect plants and animals?
Ans. (i) Leaves and stem of plants wither (ii) Skin change into dark colour (iii) Affect size of animals
Q15. What is the role of light on plants?
Ans: (i) Help in photosynthesis
(ii) Help in fruit and flower developments (iii) Help in growth of plants.
Q16. Distinguish between herbivores and carnivores?
Ans: Herbivores feed on plants where as carnivores feed on flesh of other animals.
. Q17. State any two flight adaptation in aerial animals?
Ans: 1.Hhaving streamline body shape that protect from wind
2. Having hollow bones called pneumatic bones
.
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Q18. How does temperature affect plants and animals?
Ans.
(i) Leaves and stem of plants wither
(ii) Skin change into dark colour
(iii) Affect size of animals
.Q19. What is the role of light on plants?
Ans:
(i) Help in photosynthesis
(ii) Help in fruit and flower developments
(iii) Help in growth of plants.
Q20.What types of adaptation seen in desert habitat?
Ans: (i) store water in body
(ii) Use less water to survive
(iii) Keep away from hot place
(iv) live in deep borrow
.Q.21 How biotic and abiotic components depend on each other?
Ans: Plants depends on sunlight and air for food. Animal depends on air and water for to live. Decompose dead part of
living organism and convert into organic matter that develop soil fertility. Plants also maintain purity of atmosphere.
. Q22. What is the difference between a predator and a prey?
Ans: A predator is an animal that eats other animal, whereas a prey is an animal that is eaten by a predator.
Q23.How is a cactus adapted to survive in a desert?
Ans: cactus has a waxy surface to store water. It also has thorns to reduce loss of water. It also have thick, fleshy stem.
. Q24. What is acclimisation?
Ans: Small changes that take place in body of single organism over short period to overcome the small problems due to
change in surrounding is called acclimisation.
. Q25. Give reasons: Why are deep sea worms blind?
Ans: As we move deep into seas and oceans the amount of light or the visibility decreases. Deep sea worms are blind
because of the lack of requirement. Some worms have large eyes but those are not for the purpose of seeing . These
worms have developed strong sense of smell to encounter these problems.
Q26. Give reasons: Why are some marine creatures living in the deep sea give out light of thereof own?
Ans: Since there is lack of light in deep seas, some organisms can give out light to assist them in finding their way in the
dark.This also helps them in finding prey to feed on and can also be used to find a mating partner.
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. Q27. Give reasons: Why the upper surface of the leaves of lotus have a thick cuticle ?
Ans: Lotus is an aquatic plant. The leaves of the lotus plant have a thick waxy cuticle that helps in repelling water and
keeps the stomata open so that water transport occurs effectively in plant.
Q.28 why do cockroaches hide as soon as the light is switched on?
Ans: Cockroaches cannot tolerate the high intensity light as they have some light receptors in their eyes.
. Q.29 Give two examples of non-living things which show any two characteristics of living things.
Ans: Non-living things such as clouds grow in size and also move from one place to another. Another non-living thing that
shows two of the characteristics of living things is a car which needs fuel (food) to function and also moves from one
place.to another.
NOTES OF GETTING TO KNOW PLANTS.
Herbs :
1. A herb is a non-woody plant that has green and tender stems with few branches and is usually short
2. A herb is a non-woody plant that has green and tender stems with few branches and is usually short.
3. Herbs have a variety of uses including adding flavor to food, providing medicine for diseases and in some cases even adding a
spiritual touch.
Shrubs :
1.Shrubs are taller than herbs and have stems branching out from the base.
2. The stems of shrubs are hard not but thick.
3. A common place where shrubs are grown is known as shrubbery.
Tree :
1.A tree is a woody plant that has many branches on a single stem.
2. Trees benefit us by preventing soil erosion, maintaining the carbon dioxide content in the air and in building huts and making
furniture.
Creepers
1. Creepers have a tendency to develop new plants on their own.
2. A few creepers could cause allergies or skin problems if touched.
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Climbers :
1.Climbers are plants that need support from other structures to grow and spread.
2.Climbers can either move horizontally or vertically unlike creepers that move only horizontally.
3. Climbers attracts insects and reptiles because of their brightly coloured flowers and fragrance
Root hair: The tiny thread-like structures comes over the roots are the root hair. The tip of the root is called
the root cap.
Roots are of two types - tap root and fibrous roots. :Tap root: A primary root that grows more or less straight down into the soil, and is tapered towards the end. This
main root is called the tap root.
Lateral roots: There are many smaller roots that branch out from the tap root are called lateral roots. Examples of
plants with tap roots are hibiscus, carrot, turnip and sunflower.
Fibrous roots: Many lateral roots that start from the base of the stem are called fibrous roots. Examples of plants
with fibrous roots are banana, grass and onion.
The main functions of the roots:
1. Absorb water and nutrients from the soil
2. They store food like sugars and carbohydrates
3. The roots hold the plant firmly in the soil, thereby serving as an anchor to the plant.
The main functions of the Stem:
1. Holds the leaves, flowers and fruits
2. Transport water and nutrients
vascular tissue : The vascular tissue inside the stem helps to transport water and nutrients from the roots to the
leaves, and food from the leaves to the roots.
Transpiration : Plants release excess water in the form of water vapour through minute openings in the leaves,
called the stomata. This process is known as transpiration
The different parts of a flower: The flower is the reproductive part of a plant.
1.The green leaf-like parts surrounding the bud are called the sepals. They protect the bud before it blooms into a
flower. The sepals are collectively called the calyx.
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2.The brightly coloured parts of a flower are called the petals. It helps plant to attract insects and birds for pollination
3. The male part of a flower is called the stamen, and the female part is called the pistil.
4. The sepals are collectively called the calyx.
5. The petals are collectively called the corolla.
6. In some flowers, the petals and sepals combine to form a round shape, which is called the tepal.
Fertilization: The male and female parts of a flower are involved in the formation of fruit in a process called
fertilization.
The male reproductive part of a flower: The stamen is the male reproductive part of a flower.
1. The small tube with a little bulge at the end of a stamen is called the filament.
2. The filament has a yellow sac called the anther.
3. This yellow sac contains pollen grains, which contain male reproductive cells.
The female reproductive part of a flower : Pistil consists of three parts - the stigma, the style and the ovary.
1. The upper end of the pistil is called the stigma, where pollen grains get deposited and enter the pistil.
2. The narrow tubular part is called the style, which connects the stigma to the lower part of the pistil.
3. The lower bulgy part of the pistil is called the ovary. It contains ovules.
4. The female reproductive cells are ovules.
NOTES OF SORTING MATERIALS INTO GROUPS
The word material is related to things that are around us.
· Matter is any abject around us that occupy space and has mass
· Matter can found in around us in three state Solid , liquid and Gas
· In solid state, particles of matter are tightly packed and having no gap between them. Due to this reason Solid have
definite shape and volume.
· In liquid state , particles of matter are loosely packed together have some space between then .due to this reason
liquid have fix volume but no fix shape .
· In Gas particles of matter are far from each other due to this gas have no fix volume and shape.
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· Both liquid and gas are called fluids as they can flow due to weak force of molecular attraction between particles.
· We have large numbers of material around us and we need to know about their properties. To make study of
the nature of different substance easy we have to divide it into group.
· Shorting of material into group on the basis of similarity of different substance is called Classification.
· Material around us classified on the basis of their properties:
(a) Appearance or luster (b) Hardness or softness (c) Solubility
(d) Floatation (e) Transparency
(f) Conductivity of heat and light (g) Combustibility (h) Magnetism
Q. What is luster?
Ans: Materials around us have a particular type of shine called Luster like gold, silver, aluminum etc
Q. Some metal can hammered into thin sheet without breaking into pieces. Name this property of metals?
Ans: Malleability.
Q. Some metal drawn into thin wire. Name this property of metals?
Ans: Ductility.
Q. Name material used to make chalk?
Ans: Calcium carbonate
Q. Why do houses have cement floor?
Ans: Houses have cement floor because it can polished to make attractive.
Q. Define soluble and insoluble substance?
Ans: Material that mixed with water is called soluble e.g. acid, base, milk, lemon juice, sugar and alcohol. Material
that do not mixed with water is called insoluble like oil, sand, alum etc
Q. what will happen if you drop piece of chalk and sponge in to glass of water?
Ans: Chalk and sponge absorb water due to gap between their particles.
Q. Which material you prefer to use for furniture?
Ans: Wood and Metal as they can polished and hard to break.
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Q. Classify material on the basis of conductivity?
Ans: Materials have property to conduct electricity through them. This property is called conductivity. On the basis of
that it can be divided into Good conductor and bad conductor.
A substance which conducts electricity is called good conductor like silver, copper, aluminum.
Q. Name the best conductor metal?
Ans: Silver is best conductor.
Q. Name a non metal that conduct current?
Ans: Graphite is only non metal that conduct electricity.
Q. What is the name of material that can scratch easily?
Ans: hard
Q. Name hardest and softest substance ?
Ans: Diamond and talcum powder
Q. What does cold drink contains.?
Ans: carbon dioxide gas, sugar and flavored syrup.
Q.Why axe head is made up of iron?
Ans: Because iron is cheap, hard and malleable.
Q. Defines: Solute, solvent and solution?
Ans: Solution: The mixture of two or more substance is called solution. Solute: A substance that is being dissolved is
called Solute. Solvent: The substance in which solute dissolve.
Q. Why ice floats on water?
Ans: The density of ice is lower than water so, Ice floats on water.
Q.What is transparency?
Ans: The property of substance to allow light to pass through is called transparency.
Q. What is Opaque object?
Object that do not allow light to pass is called opaque like wood, metals etc.
Object that allow light to pass partially is called Translucent. Glass, water, Oil paper etc.
Q. Why handle of utensils made up of Plastic or wood?
Ans: because Plastic or wood.
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Q. What kind of substance do we see around us?
Ans: we have two types of substance like man Plastic or wood made and natural.
Q. Why do some substance sink or others floats to the beaker field with water?
Ans: Some substances do not dissolve in water so they float unless sink.
Q. Why we can smell something e.g. perfume?
Ans: we can smell something e.g. perfume because smell the liquid floats in the air when evaporated.
NOTES ON SEPARATION OF SUBSTANCES
Q1. Why do we need to separate the components of a mixture?
Ans. Components of a mixture need to be separated in order to:
ubstance.
Q2. Name the different methods of separation of substances. ?
Ans. Different methods of separation of substances are:
Q3. Define the terms:
a) Threshing
:Threshing is the process in which stalks are beaten to separate grains from the stalks.
b) Winnowing
:Winnowing is the method of separating husk from grains with the help of wind.
Q4. What type of mixtures can be separated by hand-picking?
Ans. Hand-picking is usually used to separate those mixtures where one of the components is in small
quantity and can be easily picked up by hand. Example: stones from rice and pulses.
Q5. What is the principle behind sieving?
Ans. Sieving is used to separate those solid mixtures which have components of different sizes. Larger
particles are retained on the sieve and the smaller particles pass through the pores of the sieve.
Example: a mixture of sand and stone can be separated by using a sieve.
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Q6. Name the method of separation used for separating the following mixtures:
Ans:-MIXTURE METHOD OF SEPARATION
Iron filings and sulphur powder Magnetic separation
Husk from wheat Winnowing
Bran and flour Sieving
Mustard seeds and common salt Hand picking .
Q7. What do you mean by the terms sedimentation and decantation?
Ans. Sedimentation: it is the process of setting down the insoluble component of a mixture on leaving
undisturbed for sometime.
Decantation: The process of pouring of a liquid from a vessel without disturbing the sediment is called
decantation.
Q8. What is filtration?
Ans. The process of removing insoluble solids from a liquid by using a filter paper is known as filtration.
Q9. Discuss evaporation and condensation as methods of separation. ?
Ans. Evaporation is a method of obtaining soluble solids from their solutions by heating. In this process
the liquid changes into its vapours by heating the solution and the soluble solid is left behind.
On the other hand, condensation is the process of changing back of the hot vapours into the liquid state
by cooling.
Q10. What is a saturated solution?
Ans. A solution in which no more of solute can be dissolved in the solvent at a given temperature is
known as a saturated solution.
Q11. What happens if the saturated solution of a substance in water is:
a) heated? b) cooled?
Ans. a) If the saturated solution of a substance in water is heated then the undissolved solute will
dissolve.
b) ) If the saturated solution of a substance in water is cooled then some of the dissolved substance will
reappear in the form of solid crystals.
Q12. How is cream obtained from milk?
Ans. When milk is churned or rotated at a high speed, cream gets separated from milk.
Q13. You are given a mixture of salt & sand, how would you separate them?
Ans. For separating the given mixture of salt & sand following steps are carried out:
rated by filtration leaving behind salt solution
Q14. How would you separate a mixture of sand & iron fillings?
Ans. The mixture can be separated by the method of magnetic separation .
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NOTES ON ( AIR AROUND US)
Q1. Why do mountaineer carry oxygen cylinder whileclimbing?
Ans: This is because amount of oxygen at high altitude and become difficult to breadth.
Q2. Why does smell of perfumes reach us several meters away?
Ans: This is because air is continuously moving it takes the particle of perfumes along with it.
Q3. Why does crocodile keep it snout out of the water while resting?
Ans: Crocodile keeps it snout out of the water while resting to breathe through nostril.
Q4. Why do we see bubbles in water before it starts boiling?
Ans: This is because dissolved air is expelled out o heating.
Q5. Why do animals that live in holes or borrow in soil breadth?
Ans: They breadth in oxygen present between the soil partials.
Q6. What is the role of air in water cycle?
Ans: Air helps the water vapour to rise up to form cloud.
Q7. What does air bubbles coming out of soil, when pt in water indicates?
Ans: The presence of air
Q8. Why long chimneys are installed in factories?
Ans: To expel harmful smoke and gases away from our noses.
Q9. You have seen some tiny shining particles moving in the beam of sunlight. What are these
particles?
Ans: Dust partials presents in air.
Q10. Why does the policeman wear a mask?
Ans: vehicles produce smoke, which is bad for health therefore to avoid breathing dust partials by
covering face.
Q11. Why the transparent glass of windows, if not wiped off regularly, appears hazy?
Ans: Air contains some gases, water vapours and dust particles that stick to transparent glass of windows
and it appears hazy.
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Q12. Why during an incident of fire, one is advised to wrap a woolen blanket over a burning object.
Ans: Air presents in between the thread of woolen blanket form an insulating medium. It blocks supply of
oxygen getting to the fire and the fire goes out.
Q13. How do plants and animals maintain the balance of oxygen and CO2 in the air?
Ans: Plants take carbon dioxide to prepare food and release oxygen during daytime. This oxygen is taken
in by animals and carbon dioxide is released. Thus, plants and animals help in maintaining balance of
oxygen and carbon dioxide.
Q14. Why it advised to breathe through nose not through mouth?
Ans: This is because fine hair and mucus present inside the nose prevent dust particles from getting into
the respiratory system.
Q15. Why earthworms come out of the soil, only during heavy rains?
Ans: when it rains heavily, water fills up all the spaces occupied by the air in the soil. Therefore
earthworms have to come out for respiration.
Q16. Why all the oxygen of atmosphere does not get used up though a large number of organisms
are consuming?
Ans: This is because the balance of oxygen and carbon dioxide in the atmosphere is maintained by plants
and animals.
Q17. Why does a lump of cotton wool shrink in water?
Ans: A lump of cotton wool shrinks in water because water filled up the empty space that the air has
occupied.
Q18. Why does air quality at every place to place is not good.
Ans: It is due to the smoke and gases emitted by the automobiles along with dust particles present in the
air.
Q19. When tightly capped bottle full of water kept in the open sunlight, tiny bubbles were formed
all around inside the bottle. Why so happened?
Ans: This is because air dissolved in water starts escaping in the form of tiny bubbles due to heat from the
sun.
20. Explain reason why:
(a) A firki does not rotate in a closed area.?
Ans: A firki does not rotate in a closed area due to lack of air movement.
(b) The arrow of weather cock points towards a particular direction at a particular moment.?
Ans:The arrow of weather cock points towards a particular direction at a particular moment because
of the direction of the movement of wind.
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© An empty glass in fact is not empty.?
Ans:This is because everything is filled with air.
Q21: How do plants and animals help each other in exchange of gases in the atmosphere?
Ans:- Plants utilize carbon dioxide present in the atmosphere for the process of photosynthesis . They
release oxygen in the atmosphere. This oxygen is inhaled by humans and in tur n , carbon dioxide is
exhaled.
Q22: List five activities that are possible due to the presence of air.
Ans : (a)Respiration , (b) Photosynthesis (c)Burning (d) Movement of sailing yachts,gliders,
parachutes,airplanes. (e) Generation of electricity by windmills.
NOTES ON WATER
Q1.Why do wet clothes placed on a clothes line get dry after some time? Explain.
Ans: It is due to evaporation of water by the heat of the sun.
Q2. Wet clothes dry faster if you keep them under a fan. Why?
Ans: The rate of Evaporation increases with increase in wind speed so, Wet clothes dry faster if you
keep them under a fan.
Q3. Why are we left only tiny fraction of water for use even if about 75 % of the earth surface is
covered with water.?
Ans: This is because most of the water about 97% of surface water is in sea and ocean as salty water
that is unfit for domestic and agricultural use.
Q4. What are the various uses of water?
Ans: Water is used for various activities such as agriculture, industries, cooking, cleaning utensils,
bathing, washing clothes, and, most importantly, for drinking.
Q5. What are the three state of water?
Ans: There are three states of water
a. Solid state: ice, snow and hail
b. liquid: Rain, river, sea c. Gaseous: Water vapour.
Q 6:what is water cycle?
Ans: The circulation of water from atmosphere to the earth and vice versa is called the water cycle.
Q7:.What is evaporation?
Ans: The water present on the surface of the ocean evaporates by the sun’s heat. This process of
conversion of water from liquid state to vapour state is called evaporation.
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Q8: what is transpiration?
Ans: The excess water in plants evaporates through stomata of leaves and the stem into the air. This
process is called transpiration.
Q9. How cloud is formed?
Ans: The evaporated water above the earth surface is carried away by warm air. As the warm air moves
higher from the surface of the Earth, it starts to cool down. It is because the water vapour present starts to
condense to form tiny water droplets. These droplets float in the air and form cloud .
Q10. What is precipitation?
Ans: When clouds rub together heat is produced that melt the cloud into droplets. These droplets collect
to form bigger drops of water. Some of them may become too heavy fall down as rain. This process is
known as precipitation.
Q11 .What do you mean by infiltration?
Ans: The water from rain, rivers, lakes and ponds seeps through the soil and fills the space below the
ground. The process of seeping of water through the soil is called infiltration.
Q12. What do you mean by aquifer?
Ans: Some places groundwater is stored between layers of hard rock. This is called aquifer. Water from
aquifers is pumped and taken out through hand pumps and tube wells.
Q13. How can we conserve water?
Ans: Water conservation is process of preventing wastage of water, using water carefully and recharging
ground water. Water conservation can be done by :i) Repairing leaking pipes and taps.
ii) Not wasting water during brushing teeth, shaving, bathing, washing clothes and during other activities.
iii) Rainwater harvesting. :- Rainwater harvesting is the accumulation and deposition of rainwater for
reuse before it reaches the aquifer. Uses include water for garden, water for livestock, water for irrigation,
etc. In many places the water collected is just redirected to a deep pit with percolation.
iv) By drip irrigation of plants.
NOTES ON FUN WITH MAGNETS
Q1 How were magnets discovered?
Ans: There was a Shepard named Magnes who lived in ancient Greece .He
used to take his herd of sheep and goats to the mountains for grazing He
would take a stick with him to control his herd the stick had iron attached at
one end. One day he was surprised to find that he had to pull hard to free his
stick from a rock on the mountains. It seemed if the stick was being attracted
by the rock. The rock was a natural magnet.
Q2 What is magnetite?
Ans: Magnetite is a natural magnet It contains iron.
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Q3 What are magnets?
Ans:-Magnets are substances having property of attracting iron or iron like materials.
Q4 Name some different shapes of magnets.
Ans : 1. Bar magnet
2. horse shoe magnet
3. cylindrical magnet
4. ball ended magnet
5. needle magnet
Q5 What are magnetic and non magnetic materials?
Ans: The materials which get attracted to magnets are known as magnetic materials example: iron nickel
cobalt. The materials which do not get attracted to magnets are known as non magnetic materials
example plastic rubber wood.
Q6 Demonstrate what happens when we move a bar magnet through iron
filings (draw the diagram also) .
Ans: When we move bar magnet through iron filings they get attracted to magnet. Minimum iron filings get
attached to the centre region and maximum iron filings get attached to the end regions of bar magnet
which is known as the poles showing the attraction is maximum at the poles.
Q7 How many poles exist in a magnet?
Ans: Every magnet has two poles north pole and a south pole. North Pole is denoted by N and South
Pole is denoted by S .
Q8 What is the property of magnet which is used by travelers to find directions?
Ans: When we freely suspend a magnet it always points in N-S direction
This property is used by travelers to find directions ..
Q9 What is a magnetic compass?
Ans: A device which was developed based on the property of magnets of finding directions is known as
magnetic compass.
A compass is usually a small box with glass cover on it A magnetized needle is pivoted inside the box
which can rotate freely The compass also has a dial with directions marked on it Its needle indicates north
south directions when it comes to rest.
Q10 How can you prepare your own magnet?
Ans: We can prepare magnet by the following processes
1. By rubbing one pole without lifting 20-30 times on an iron nail
or iron strip.
2. By passing current through an iron nail or iron strip we obtain a
magnet and this magnet is known as electromagnet.
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Q11 what happens when we bring like poles of a magnets close to one another?
Ans: Like poles repel.
Q12 what happens when we bring unlike poles of a magnets close to one another?
Ans: Unlike poles attract.
Q13 How do magnets lose their properties?
Ans: Magnets loose their property if they are heated, hammered or dropped from some height.
Q14 How can we keep our magnets safe?
Ans: To keep magnets safe Bar magnets should be kept in pairs with unlike poles on same side They
must be separated by a piece of wood while two pieces of soft iron should be placed across their ends
For horse shoe magnet one should keep a piece of iron across the poles.
Q15 what precautions should be taken in handling magnets?
Ans: We should keep magnets away from cassettes, mobiles, TV music systems compact disks and
computers.
Q16 Why magnet called load stone?
Ans: Magnet in the form of a bar was used to find directions on the earth, and so it is called as a
Lodestone.
Q17:- What are different types of magnets?
Ans: Bar magnets : In these magnets, the poles are located at the ends of the bar.
Cylindrical magnets: In these magnets, the poles are located at the two circular ends of the
cylinder.
Horseshoe magnets : In these magnets, the poles are located at the two free ends of the 'U'
shape.
Q18:- What are magnetic keepers?
Ans: A soft iron pieces placed across the ends of a pairs of bar magnets to preserve the
magnetism for a long time is called magnetic keepers.
Q19: Write any two properties of magnet?
Ans:- Properties of magnets are :1) Each magnet has two poles i.e. North pole (N) and South Pole (p).
2) Opposite poles of two magnets attract each other while like poles of two magnet repel each
other.
3) A freely suspended magnet always aligns in N-S direction.
ALL THE BEST
Prashant Kumar (8447944520)
utkarshacademy786@gmail.com
PRASHANT KUMAR (8447944520)
utkarshacademy7.webnode.com
.
Prashant Kumar (8447944520)
utkarshacademy786@gmail.com