CBSE Class 7 Science Revision Worksheet Set 18

Chapter 1 : Nutrition in Plants

Fill in the blanks :

1. The components of food which are necessary for our body are called _______________

2. Green plants synthesise their own food themselves by the process of __________________.

3. ______________________ is the mode of taking food by an organism and its utilization by the body.

4. Complex chemical substances such as ______________ are the products of photosynthesis.

5. ___________________ gas is produced during photosynthesis.

6. Organisms that are dependent on others for their nutrition are called ______________________

7. _________________ are the tiny pores present on the surface of the leaves and are surrounded by guard cells.

8. ____________________is the ultimate source of energy for all living organisms.

9. Organisms which derive their nutrition from dead decaying matter are called _______________.

10. Some organisms live together and share shelter and nutrients, this is called _____________________.

11. Carbohydrates are made up of _________,__________ and __________.

Name the following :

1. A bacterium that can take atmospheric nitrogen and convert it into a soluble form.

2. An insectivorous plant.

3. The mode of nutrition in mushrooms.

Learn and write the following questions and answers.

Question 1: What are the components of food?
Answer: Carbohydrates, proteins, fats, vitamins and minerals are the components of food.

Question 2: What is nutrition?
Answer: The process of utilization of food by a living organism to obtain energy is called nutrition.

Questions 3: What is autotroph?
Answer: Organisms that make their food themselves are called autotrophs.

Question 4: What is autotrophic mode of nutrition?
Answer: The mode of nutrition in which the organism makes its own food is called autotrophic mode of nutrition.

Question 5: Give some example of autotrophs.
Answer: All green plants, such as grass, mango, bougainvillea, etc. are the examples of autotrophs. Some bacteria also show autotrophic nutrition. Question

6: What is heterotrophic mode of nutrition?
Answer: The mode of nutrition in which an organism takes food from another organism is called heterotrophic mode of nutrition. The nutrition in animals and non-green plants is the example of heterotrophic mode of nutrition.

Question 7: Give examples of Heterotrophs.
Answer: Animals and non green plants are the examples of heterotrophs.

Question 8: What are saprotrophs?
Answer: Organisms which get their nutrition from dead or decaying plants in liquid form are called saprotrophs.

Question 9: What is the ultimate source of energy?
Answer: Sun is the ultimate source of energy.

Question 10: Why do farmers add nitrogenous fertilizers to the soil?
Answer: Farmers add nitrogenous fertilizers to the soil to fulfill the requirement of nitrogen of the plants. Nitrogen is necessary to synthesize proteins.

Chapter 1: Nutrition in Plants

Fill in the Blanks

Question 1. The components of food which are necessary for our body are called _______________
Answer: nutrients
In simple words: Nutrients are the useful parts of food that our body needs to stay healthy.

Exam Tip: Learn the five main nutrients: carbohydrates, fats, proteins, vitamins, and minerals.

Question 2. Green plants synthesise their own food themselves by the process of __________________.
Answer: photosynthesis
In simple words: Photosynthesis is how green plants make their meals using sunlight, water, and air.

Exam Tip: Remember that "photo" means light and "synthesis" means putting together.

Question 3. ______________________ is the mode of taking food by an organism and its utilization by the body.
Answer: Nutrition
In simple words: Nutrition means eating food and using it to grow and get energy.

Exam Tip: Be sure to write both aspects: intake of food and its use by the body.

Question 4. Complex chemical substances such as ______________ are the products of photosynthesis.
Answer: carbohydrates
In simple words: Plants make sugars called carbohydrates during photosynthesis.

Exam Tip: Glucose and starch are both forms of carbohydrates produced by green leaves.

Question 5. ___________________ gas is produced during photosynthesis.
Answer: Oxygen
In simple words: Plants release oxygen into the air while they prepare their food.

Exam Tip: Do not confuse oxygen (released) with carbon dioxide (taken in) during photosynthesis.

Question 6. Organisms that are dependent on others for their nutrition are called ______________________
Answer: heterotrophs
In simple words: Living things that cannot make their own food are called heterotrophs.

Exam Tip: All animals, including humans, belong to the group called heterotrophs.

Question 7. _________________ are the tiny pores present on the surface of the leaves and are surrounded by guard cells.
Answer: Stomata
In simple words: Stomata are tiny breathing holes on leaves guarded by special cells.

Exam Tip: Mention guard cells when describing how stomatal pores open and close.

Question 8. ____________________is the ultimate source of energy for all living organisms.
Answer: The Sun
In simple words: The sun provides energy to plants, which feeds all other life on Earth.

Exam Tip: State that solar energy enters the living world through plant photosynthesis.

Question 9. Organisms which derive their nutrition from dead decaying matter are called _______________.
Answer: saprotrophs
In simple words: Creatures that take food from rotting plants and dead animals are saprotrophs.

Exam Tip: Fungi such as bread mould and mushrooms are common examples of saprotrophs.

Question 10. Some organisms live together and share shelter and nutrients, this is called _____________________.
Answer: symbiosis
In simple words: Symbiosis is a friendly partnership where two organisms live together and help each other.

Exam Tip: Lichens are the best example of a symbiotic partnership between an alga and a fungus.

Question 11. Carbohydrates are made up of _________,__________ and __________.
Answer: carbon, hydrogen, and oxygen
In simple words: Carbohydrates contain three chemical building blocks: carbon, hydrogen, and oxygen.

Exam Tip: Remember that plants add nitrogen to these three elements to build proteins.

Name the Following

Question 1. A bacterium that can take atmospheric nitrogen and convert it into a soluble form.
Answer: Rhizobium
In simple words: Rhizobium is a friendly microbe living in plant roots that fixes nitrogen from the air.

Exam Tip: Rhizobium lives inside root nodules of leguminous plants like gram and peas.

Question 2. An insectivorous plant.
Answer: Pitcher plant
In simple words: A pitcher plant catches and digests bugs to get extra nutrients.

Exam Tip: Venus flytrap and sundew are also correct examples of insect-eating plants.

Question 3. The mode of nutrition in mushrooms.
Answer: Saprotrophic nutrition
In simple words: Mushrooms absorb dissolved food from rotting organic waste.

Exam Tip: Mushrooms lack chlorophyll and cannot perform photosynthesis.

Question 4. The indicator used to test the presence of starch in leaves.
Answer: Iodine solution
In simple words: Dropping brown iodine onto starch turns it blue-black.

Exam Tip: The appearance of a blue-black colour confirms that starch is present in the leaf.

II) Write True or False

Question 1. Some fungi are used in medicines.[ ]
Answer: True
In simple words: Useful fungi help us make life-saving medicines like penicillin.

Exam Tip: Penicillium is a well-known fungus used to produce antibiotics.

Question 2. Most of the pulses are obtained from leguminous plants. [ ]
Answer: True
In simple words: Beans, peas, and lentils come from leguminous plants with root nodules.

Exam Tip: Legumes enrich the soil with nitrogen and reduce the need for fertilizers.

Question 3. Cuscuta (Amarbel) is a host.[ ]
Answer: False
In simple words: Cuscuta is a parasite, while the green tree it climbs on is the host.

Exam Tip: Cuscuta has yellow rope-like stems and takes ready-made food from the host tree.

Question 4. Lichens, an alga and a fungus show symbiotic relationship. [ ]
Answer: True
In simple words: In a lichen, the alga makes food and the fungus provides shelter.

Exam Tip: This mutual partnership helps both organisms survive in harsh conditions.

Question 5. In desert plants, green stems carry out photosynthesis.[ ]
Answer: True
In simple words: Desert plants turn their leaves into spines, so their green stems make food.

Exam Tip: Modifying leaves into spines cuts down water loss through transpiration.

III) Define the Following

Question 1. Autotrophs
Answer: Autotrophs are living beings that make their own food from basic raw materials found in nature.
In simple words: Autotrophs are self-feeders like green plants that make food using sunlight.

Exam Tip: Always give green plants as the standard example of autotrophs.

Question 2. Saprotrophs
Answer: Saprotrophs are organisms that feed by taking in liquid nutrients from decaying organic matter.
In simple words: These are organisms that digest rotting plant or animal remains for food.

Exam Tip: Mention that they release digestive juices directly onto dead matter.

Question 3. Heterotrophs
Answer: Heterotrophs are organisms that cannot produce their own meals and depend on plants or other animals.
In simple words: Heterotrophs are creatures that must eat other living things to survive.

Exam Tip: Include herbivores, carnivores, and omnivores under this category.

Question 4. Nutrition
Answer: Nutrition is the complete process by which an organism takes in food and uses it for energy and growth.
In simple words: Nutrition means getting food and putting its nutrients to work inside the body.

Exam Tip: Emphasize both steps: food intake and bodily utilization.

IV) Diagrams

Question 1. Cell
Answer: A cell is the basic structural unit of living things. It has a protective outer cell membrane, a central control center called the nucleus, and a jelly-like fluid called cytoplasm.

In simple words: A cell has a skin outside, jelly in the middle, and a central brain called the nucleus.

Exam Tip: Clearly label the cell membrane, cytoplasm, and nucleus to earn full marks.

Question 2. Photosynthesis in plants.
Answer: During photosynthesis, green leaves capture solar energy with chlorophyll. They combine carbon dioxide from the air and water from the soil to create glucose, releasing oxygen gas.

In simple words: Leaves use sunlight, water, and air to build food and breathe out oxygen.

Exam Tip: Show arrows pointing inward for water, carbon dioxide, and sunlight, and outward for oxygen.

Fill in the Blanks

Question 1. The mode of taking food into the body is called ___________________
Answer: ingestion
In simple words: Putting food into your mouth is called ingestion.

Exam Tip: Ingestion is the very first step in human nutrition.

Question 2. In the process of ________________ food is broken down in to simpler substances.
Answer: digestion
In simple words: Digestion breaks big food lumps into tiny bits that your body can absorb.

Exam Tip: Digestion turns complex, insoluble meals into simple, soluble molecules.

Question 3. The _______________ canal start with mouth and ends in anus.
Answer: alimentary
In simple words: The alimentary canal is the continuous food tube running through your body.

Exam Tip: It is also called the digestive tract and is roughly 9 meters long.

Question 4. ___________________glands are present in mouth.
Answer: Salivary
In simple words: Salivary glands make saliva to wet and break down your food.

Exam Tip: Humans have three pairs of salivary glands inside the buccal cavity.

Question 5. Saliva helps in the digestion of ___________________ in food.
Answer: starch
In simple words: Saliva starts changing complex starch into simple sugar right in your mouth.

Exam Tip: Salivary amylase is the enzyme that converts starch into maltose sugar.

Question 6. _____________ are the sensory cells present in mouth.
Answer: Taste buds
In simple words: Taste buds on your tongue sense sweet, salty, sour, and bitter flavors.

Exam Tip: Different zones of the tongue detect different basic tastes.

Question 7. The digestive juices of the stomach digest the _____________ in the food.
Answer: proteins
In simple words: Stomach juices start breaking down proteins into smaller units.

Exam Tip: The stomach enzyme pepsin works only in an acidic environment created by hydrochloric acid.

Question 8. The ________________released by the bacteria in the mouth causes tooth decay.
Answer: acid
In simple words: Germs feast on leftover sugar and make acid that eats through tooth enamel.

Exam Tip: Regular brushing removes plaque and neutralizes mouth acids.

Question 9. Liver secretes ____________ and helps in the digestion of ____________in the food.
Answer: bile juice, fats
In simple words: The liver produces bitter green bile to help digest oily fats.

Exam Tip: Bile is stored inside a small sac called the gall bladder before reaching the small intestine.

Question 10. During the process of digestion, the carbohydrates break down to _________, the proteins into ______________ and the fats into ______________.
Answer: glucose, amino acids, fatty acids and glycerol
In simple words: Digestion turns carbs into glucose, proteins into amino acids, and fats into fatty acids.

Exam Tip: These end products are small enough to pass through intestinal villi into the blood.

Question 11. Faecal matter is removed from the body by the process of __________
Answer: egestion
In simple words: Pushing undigested solid waste out through the anus is called egestion.

Exam Tip: Do not confuse egestion (removing undigested food) with excretion (removing metabolic waste like urine).

Question 12. _____________ of amoeba helps to capture food.
Answer: Pseudopodia
In simple words: Amoeba uses finger-like false feet to wrap around its prey.

Exam Tip: Pseudopodia also help the single-celled Amoeba move around.

Question 13. The patient suffering diarrhea should be treated with ___________.
Answer: Oral Rehydration Solution (ORS)
In simple words: Drinking boiled water with salt and sugar cures dehydration during loose motions.

Exam Tip: ORS restores water and lost body salts quickly to prevent severe dehydration.

Question 14. We get hiccups or cough, if by chance food particles enters the ____
Answer: windpipe
In simple words: Coughing happens when swallowed food slips into the breathing pipe by mistake.

Exam Tip: The flap-like epiglottis normally blocks the windpipe while swallowing.

Question 15. Partially digested food in the rumen of herbivores is called ________
Answer: cud
In simple words: Cud is half-chewed grass that cattle bring back up to chew again.

Exam Tip: Grazing animals chew cud while resting to digest plant cellulose thoroughly.

Question 16. The process of utilizing absorbed food particles(nutrients) into the living cells is called ________________.
Answer: assimilation
In simple words: Assimilation happens when your body cells use digested nutrients to build tissues and release energy.

Exam Tip: Memorize the five stages in order: ingestion, digestion, absorption, assimilation, and egestion.

II) Name the Following

Question 1. 4 types of teeth.
Answer: Incisors, canines, premolars, and molars
In simple words: We have flat cutting incisors, pointy canines, and broad chewing premolars and molars.

Exam Tip: An adult human mouth has 8 incisors, 4 canines, 8 premolars, and 12 molars.

Question 2. Digestive glands in human body.
Answer: Salivary glands, liver, and pancreas
In simple words: These three organs release chemical juices that break down your food.

Exam Tip: The liver is the largest gland in the human body.

Question 3. Acid produced in stomach.
Answer: Hydrochloric acid
In simple words: The stomach makes strong hydrochloric acid to kill germs and help digest proteins.

Exam Tip: The inner stomach lining secretes mucus to shield itself from this acid.

Question 4. Scientist who discovered the working of stomach.
Answer: Dr. William Beaumont
In simple words: Dr. Beaumont studied digestion through a gunshot wound in a patient's stomach.

Exam Tip: He made his discoveries by treating a wounded Canadian soldier named Alexis St. Martin.

Question 5. The sac like structure present between the small intestine & large intestine in ruminants.
Answer: Caecum
In simple words: The caecum is a pouch where bacteria break down tough grass fibers in plant-eaters.

Exam Tip: Humans cannot digest cellulose because our digestive system lacks this functional pouch.

True or False

Question 1. Canines are meant for tearing flesh.[ ]
Answer: True
In simple words: Canines are sharp pointed teeth built to rip through meat.

Exam Tip: Carnivores have long, sharp canines specifically for holding and tearing prey.

Question 2. Oesophagus is also known as food pipe.[ ]
Answer: True
In simple words: The oesophagus is the muscular tube that carries food from your throat to your stomach.

Exam Tip: Food moves down the food pipe by rhythmic muscle contractions called peristalsis.

Question 3. Mouth cavity contains teeth and salivary glands only.[ ]
Answer: False
In simple words: The mouth also contains the tongue, so this statement is false.

Exam Tip: The tongue mixes food with saliva and carries taste buds.

Question 4. Deer is a ruminant.[ ]
Answer: True
In simple words: Deer swallow grass quickly into a rumen and chew the cud later on.

Exam Tip: Cattle, goats, sheep, and deer are all cud-chewing ruminants.

Question 5. Large intestine is longer than small intestine. [ ]
Answer: False
In simple words: The small intestine is about 7.5 meters long, while the large intestine is only 1.5 meters long.

Exam Tip: The large intestine is named for its wider width, not its length.

Define

Question 1. Digestion.
Answer: Digestion is the biochemical breakdown of complex food particles into simple, water-soluble substances that the body can absorb.
In simple words: Digestion breaks down food into small bits so your blood can absorb them.

Exam Tip: Include the words "complex substances" and "simpler substances" in your definition.

Question 2. Rumination
Answer: Rumination is the process where grazing animals bring partially digested cud back from the stomach to the mouth to chew it thoroughly.
In simple words: Rumination means bringing half-chewed food back into the mouth to chew it again.

Exam Tip: Grass contains cellulose, which requires this two-step chewing process to break down.

Distinguish Between

Question. Milk teeth and permanent teeth
Answer: Milk teeth form the temporary first set of 20 teeth that appear during infancy and drop out between the ages of six and eight years. Permanent teeth form the second set of 32 teeth that replace the milk teeth and stay throughout adult life.
In simple words: Baby teeth fall out during childhood, while permanent teeth grow in to last for life.

Exam Tip: State the exact count: 20 temporary milk teeth versus 32 permanent teeth.

Draw and Label

Question 1. The human digestive system
Answer: The human digestive system consists of the alimentary canal and connected glands, starting at the mouth, passing through the stomach and intestines, and ending at the anus.

In simple words: The digestive tract is a long tube with the mouth, stomach, and intestines working together.

Exam Tip: Practice labeling the liver, stomach, small intestine, and large intestine accurately.

Question 2. The feeding and digestion in Amoeba
Answer: Amoeba wraps its pseudopodia around a food particle to form a food vacuole. Digestive juices enter the vacuole to break down the food, and undigested waste is expelled outside.

In simple words: Amoeba catches food with its false feet and digests it inside a food bubble.

Exam Tip: Be sure to label the nucleus, pseudopodium, and food vacuole.

Chapter 3: Fibre to Fabric

Fill in the Blanks

Question 1. Wool is obtained from the ______________ of the sheep or yak.
Answer: fleece
In simple words: Wool is made from the hairy coat of sheep and yaks.

Exam Tip: The term "fleece" refers to the hairy skin of wool-bearing animals.

Question 2. __________ is the name of the breed of sheep from which we get Kashmiri shawls.
Answer: Bakharwal
In simple words: Bakharwal sheep give warm wool used for weaving Kashmiri shawls.

Exam Tip: Pashmina shawls come from Kashmiri goats, while Bakharwal sheep provide woollen shawls.

Question 3. By the process of _____________ we get off springs with special characters.
Answer: selective breeding
In simple words: Choosing good parent animals helps breed babies with fine, soft wool.

Exam Tip: Farmers select parents with soft under-hair to produce better wool breeds.

Question 4. Washing of sheared skin is known as ______________
Answer: scouring
In simple words: Scouring washes away grease, dust, and dirt from freshly cut wool.

Exam Tip: Scouring is performed in large tanks or machines after shearing.

Question 5. In __________ the hairs of different textures are separated.
Answer: sorting
In simple words: Sorting separates hairy wool by quality, length, and texture.

Exam Tip: Factory workers who perform sorting can be exposed to anthrax bacteria.

Question 6. Silk fibre is made up of a __________
Answer: protein
In simple words: Silk threads are natural fibers made of strong animal proteins.

Exam Tip: Both wool and silk are animal fibers composed of proteins.

Question 7. The silk fibre is obtained from the covering of pupa known as ______________
Answer: cocoon
In simple words: A caterpillar spins a silk ball called a cocoon around itself.

Exam Tip: Cocoons are boiled in hot water to unwind the delicate silk threads.

Question 8. The larva of silk worm are called______________
Answer: caterpillars
In simple words: Baby silkworms that hatch from eggs are called caterpillars.

Exam Tip: Caterpillars feed continuously on fresh mulberry leaves for about a month.

Question 9. Inside cocoon, the pupa develops into ______________
Answer: silk moth
In simple words: The resting pupa inside the cocoon turns into an adult silk moth.

Exam Tip: Review the complete life cycle: egg → caterpillar → pupa (cocoon) → moth.

Name the Following

Question 1. Two wool giving animals.
Answer: Sheep and yak
In simple words: Sheep and yaks are common animals raised for warm wool.

Exam Tip: Camels, llamas, and Angora goats are also correct examples.

Question 2. Two Indian breeds of sheep.
Answer: Lohi and Nali
In simple words: Lohi gives good wool, and Nali sheep provide carpet wool.

Exam Tip: Marwari (coarse wool) and Bakharwal (shawl wool) are other Indian breeds.

Question 3. Two types of silk.
Answer: Tassar silk and Mooga silk
In simple words: Tassar and Mooga are two popular wild silks from India.

Exam Tip: Eri silk is another common variety alongside Mulberry silk.

Question 4. Name the most common silk.
Answer: Mulberry silk
In simple words: Mulberry silk is the most popular, shiny, and soft commercial silk.

Exam Tip: It is produced by the domestic silk moth Bombyx mori feeding on mulberry leaves.

Question 5. Bacterium which causes sorter’s disease.
Answer: Bacillus anthracis
In simple words: Anthrax bacteria cause a dangerous blood disease in wool sorting factories.

Exam Tip: Sorter's disease is an occupational hazard faced by workers handling raw fleece.

Question 6. The country from where silk industry started.
Answer: China
In simple words: China invented sericulture and kept it secret for hundreds of years.

Exam Tip: Ancient trade routes used to carry silk from China were called the Silk Route.

Question 7. Process of taking out silk – threads from cocoon.
Answer: Reeling the silk
In simple words: Reeling means unwinding thin silk threads from cooked cocoons.

Exam Tip: Special reeling machines unwind three to eight delicate fibers together into thread.

Write True or False

Question 1. Soft silk yarn is strong as comparable thread of steel.
Answer: True
In simple words: A strand of silk has amazing strength equal to a thin steel wire.

Exam Tip: Silk is the strongest natural textile fiber known.

Question 2. Shearing hurts the sheep.
Answer: False
In simple words: Shaving wool does not hurt sheep because the top skin layer is dead.

Exam Tip: Shearing is like getting a haircut; it is painless when done properly.

Question 3. Small fluffy fibres are called burrs.
Answer: True
In simple words: Burrs are little fuzzy fuzzballs that get picked out of raw wool.

Exam Tip: Wool fibers are scoured again after burrs are removed.

Define

Question. • Shearing
Answer: Shearing is the removal of the sheep's wool fleece along with a thin top layer of dead skin.
In simple words: Shearing means shaving off the wool coat from a sheep in warm weather.

Exam Tip: Shearing is usually carried out in summer so the sheep stay cool and grow back fleece before winter.

Question. • Seri culture.
Answer: Sericulture is the commercial breeding and rearing of silkworms for producing raw silk thread.
In simple words: Sericulture means raising silkworms on mulberry leaves to collect silk.

Exam Tip: This industry combines mulberry tree farming with silkworm rearing.

Question. • Selective breeding
Answer: Selective breeding is the method of choosing parent animals to pass desirable traits, like soft wool, to their offspring.
In simple words: Farmers pick parent animals with the finest traits to produce better young ones.

Exam Tip: This technique helps produce sheep breeds that yield higher amounts of fine under-hair.

Question. • Rearing
Answer: Rearing involves caring for, feeding, sheltering, and breeding domestic animals for useful products like wool or milk.
In simple words: Rearing means looking after farm animals so they grow healthy and useful.

Exam Tip: Sheep rearing includes providing green grass, dry fodder, oil cakes, and clean shelter.

Chapter 4: Heat

Fill in the Blanks

Question 1. ______________ is a device used for measuring temperature.
Answer: Thermometer
In simple words: A thermometer tells us how hot or cold something is.

Exam Tip: Most traditional thermometers use liquid mercury or alcohol to show temperature readings.

Question 2. The materials which allow heat to pass through them easily are __________ of heat.
Answer: conductors
In simple words: Conductors are materials that let heat flow through them very quickly.

Exam Tip: Metals like copper, aluminum, and iron are good conductors of heat.

Question 3. Clinical thermometer is used to measure our _____________
Answer: body temperature
In simple words: Doctors use a clinical thermometer to check whether a person has a fever.

Exam Tip: Its scale is restricted to the human body range from 35 °C to 42 °C.

Question 4. Wool is poor __________________ of heat and it has air trapped in between the fibres.
Answer: conductor
In simple words: Wool stops body heat from escaping because trapped air keeps you warm.

Exam Tip: Trapped air acts as an insulator between your warm body and chilly winter air.

Question 5. In ______________ generally the heat is transferred by conduction.
Answer: solids
In simple words: Conduction moves heat through solid objects from the hot end to the cold end.

Exam Tip: In solids, closely packed particles pass on vibrations without leaving their fixed places.

Question 6. _______________ metal is used in the bulb of the thermometer.
Answer: Mercury
In simple words: Silvery liquid mercury expands evenly inside a thermometer tube when heated.

Exam Tip: Mercury is used because it stays liquid across a wide temperature range and does not stick to glass.

Question 7. The normal temperature of the human body is __________
Answer: 37 °C (or 98.6 °F)
In simple words: A healthy human body normally stays around 37 degrees Celsius.

Exam Tip: Always write the unit (°C or °F) along with the number.

True or False

Question 1. The materials which do not allow heat to pass them easily are called insulators.
Answer: True
In simple words: Insulators like plastic and wood block the easy flow of heat.

Exam Tip: Pan handles are made of insulators to keep hands from burning.

Question 2. In liquids and gases the heat is transferred by conduction.
Answer: False
In simple words: Heat travels through liquids and gases by convection currents, not conduction.

Exam Tip: Convection requires fluid particles to move from hotter regions to cooler regions.

Question 3. A kink near the bulb of a clinical thermometer prevents mercury level from falling of its own.
Answer: True
In simple words: The tiny kink keeps mercury from slipping back so you can read temperature accurately.

Exam Tip: You must jerk the clinical thermometer downward to reset the mercury below the kink.

Question 4. We get heat from the sun by radiation.
Answer: True
In simple words: Sunlight warms Earth through empty space without needing air or solid material.

Exam Tip: Radiation is the only heat transfer method that works across a vacuum.

Question 5. Digital thermometers contain mercury.
Answer: False
In simple words: Modern digital thermometers use safe electronic sensors and zero mercury.

Exam Tip: Digital thermometers were developed because mercury is toxic and hard to clean up if broken.

Define

Question 1. Temperature
Answer: Temperature is a reliable numerical measurement of the degree of hotness or coldness of an object.
In simple words: Temperature tells us how hot or cold something is using numbers.

Exam Tip: The standard scientific unit of temperature is the Kelvin, while degrees Celsius is commonly used.

Question 2. Radiation
Answer: Radiation is the transfer of heat energy by waves that does not require any physical substance to travel through.
In simple words: Radiation is heat travelling in straight rays through empty space.

Exam Tip: Every hot body emits heat into its surroundings through thermal radiation.

Question 3. Conduction
Answer: Conduction is the process of heat transfer from the warmer end to the cooler end of an object without the bulk movement of its particles.
In simple words: Conduction is heat moving directly through a solid object from atom to atom.

Exam Tip: Good thermal contact between two objects is needed for conduction to happen.

Question 4. Convection
Answer: Convection is the mode of heat transfer in fluids where heated, lighter portions rise and cooler, heavier portions sink to take their place.
In simple words: Convection warms water or air as hot fluid floats up and cold fluid sinks down.

Exam Tip: Sea breezes and land breezes in coastal areas are natural examples of convection currents.

Name the Following

Question 1. The movement of cool air from land towards sea.
Answer: Land breeze
In simple words: Cool night air blowing off the land toward the ocean is a land breeze.

Exam Tip: Land breeze blows at night because land cools down much faster than seawater.

Question 2. Two conductors of heat
Answer: Copper and aluminum
In simple words: Copper and aluminum are metals that transfer heat very quickly.

Exam Tip: Cooking pots are commonly built with copper or aluminum bottoms for fast heating.

Question 3. Two insulators of heat
Answer: Wood and plastic
In simple words: Wood and plastic do not let heat through easily.

Exam Tip: Glass, rubber, and air are also good examples of heat insulators.

Distinguish Between

Question. • Conductors and insulators.
Answer: Conductors are materials that let heat flow through them easily, such as iron, copper, and aluminum. In contrast, insulators are materials that resist the transfer of heat, such as wood, plastic, and rubber.
In simple words: Conductors allow heat to travel freely, while insulators block heat.

Exam Tip: Give at least one clear everyday example for both conductors and insulators.

Question. • Clinical and laboratory thermometer
Answer: A clinical thermometer measures human body temperature across a narrow scale from 35 °C to 42 °C and includes a kink near the bulb. A laboratory thermometer measures general temperatures in science experiments across a broad scale from -10 °C to 110 °C and does not have a kink.
In simple words: Clinical thermometers check body fevers with a kink, while lab thermometers measure boiling chemicals without a kink.

Exam Tip: State the temperature ranges clearly: 35 °C to 42 °C versus -10 °C to 110 °C.

Diagram

Question. Clinical Thermometer and Laboratory Thermometer
Answer: A clinical thermometer has a bent kink above its mercury bulb to hold the reading steady. A laboratory thermometer is longer, reads from -10 °C to 110 °C, and has a straight bore with no kink.

In simple words: The clinical thermometer has a kink to freeze the reading, while the long lab thermometer does not.

Exam Tip: Be sure to highlight the kink on the clinical thermometer stem.

Chapter 5: Acids, Bases and Salts

Fill in the Blanks

Question 1. Spinach contains_____________ acid while tamarind contains ________________ acid.
Answer: oxalic, tartaric
In simple words: Spinach leaves have oxalic acid and sour tamarind has tartaric acid.

Exam Tip: Remember: apples contain malic acid, vinegar contains acetic acid, and citrus fruits contain citric acid.

Question 2. The gas which escapes out from many aerated soft drink is _____________
Answer: carbon dioxide
In simple words: Bubbly soda drinks fizz because dissolved carbon dioxide escapes into the air.

Exam Tip: Carbon dioxide forms weak carbonic acid when dissolved in water under pressure.

Question 3. Carbon burns in air to form _______________
Answer: carbon dioxide
In simple words: Coal or charcoal burns with oxygen in the air to produce carbon dioxide gas.

Exam Tip: The balanced word equation is: Carbon + Oxygen → Carbon dioxide.

Question 4. The chemical name of lime water is ______________
Answer: calcium hydroxide
In simple words: Clear lime water is chemically known as calcium hydroxide solution.

Exam Tip: Its chemical formula is \( \text{Ca(OH)}_2 \), which is a basic solution.

Question 5. _______________ is the reaction between an acid and base.
Answer: Neutralization
In simple words: When an acid cancels out a base to make salt and water, it is called neutralization.

Exam Tip: Heat is always released during a neutralization reaction.

Question 6. An aqueous solution of sodium oxide changes ________________ litmus to blue.
Answer: red
In simple words: Sodium oxide forms a basic solution in water, so it turns red litmus blue.

Exam Tip: Metallic oxides are basic in nature and turn red litmus paper blue.

Question 7. Phenolphthalein indicator turns acidic solutions to ______________ and basic solutions to _____________.
Answer: colourless, pink
In simple words: Phenolphthalein stays clear in acid but turns bright pink in a base.

Exam Tip: Phenolphthalein is completely colorless in acidic and neutral solutions.

Question 8. The chemical name of moist baking soda is _____________
Answer: sodium hydrogen carbonate
In simple words: Baking soda is chemically called sodium hydrogen carbonate.

Exam Tip: Sodium bicarbonate is another widely used name for this base.

Question 9. Calamine solution contains __________________( a base ).
Answer: zinc carbonate
In simple words: Calamine lotion contains zinc carbonate to soothe itchy insect bites.

Exam Tip: It neutralizes acidic formic acid injected during an ant sting.

Question 10. Litmus is obtained from the _____________________
Answer: lichens
In simple words: Natural purple litmus dye is extracted from lichen plants.

Exam Tip: In pure distilled water, natural litmus dye has a mauve (purple) shade.

Question 11. Curd contains __________ while vinegar contains ___________
Answer: lactic acid, acetic acid
In simple words: Sour curd contains lactic acid, and kitchen vinegar contains acetic acid.

Exam Tip: Both of these are mild organic acids that are safe to eat.

Complete the Following Word Equations

Question 1. Zinc + hydrochloric acid → ___________+ _____________
Answer: Zinc chloride + Hydrogen
In simple words: Zinc metal reacts with hydrochloric acid to form zinc chloride salt and hydrogen gas bubbles.

Exam Tip: Hydrogen gas burns with a characteristic pop sound when tested with a lighted matchstick.

Question 2. Sodium hydroxide + Hydrochloric acid → ___________+ ________
Answer: Sodium chloride + Water
In simple words: Mixing these two strong chemicals creates table salt and plain water.

Exam Tip: This is the classic example of a neutralization reaction between a strong acid and a strong base.

Question 3. Calcium hydroxide + sulphuric acid → _____________+ ________
Answer: Calcium sulphate + Water
In simple words: Calcium hydroxide neutralizes sulfuric acid to produce calcium sulfate salt and water.

Exam Tip: Acid + Base → Salt + Water is the universal neutralization rule.

True or False

Question 1. All acids turn blue litmus red. True / False
Answer: True
In simple words: Any acidic liquid turns blue litmus paper red.

Exam Tip: A useful memory trick is: Acid turns Blue to Red (A-B-R).

Question 2. Neutral solution can change the colour of litmus. True / False
Answer: False
In simple words: Pure water or salt solutions do not change the color of red or blue litmus.

Exam Tip: Neutral solutions show no reaction with either red or blue litmus.

Question 3. Orange juice turns blue litmus red. True / False
Answer: True
In simple words: Orange juice has citric acid, which turns blue litmus paper red.

Exam Tip: All sour fruit juices are acidic and give a positive red litmus test.

Question 4. Substances which are neither acidic nor basic are called neutral. True/ False
Answer: True
In simple words: Things that are neither acids nor bases are called neutral.

Exam Tip: Distilled water, sugar solution, and common salt solution are neutral.

Question 5. An acid and a base neutralize each other and from a salt. True / False.
Answer: True
In simple words: Acid and base cancel each other out to make salt and water.

Exam Tip: The produced salt may be acidic, basic, or neutral depending on reactant strengths.

Question 6. China rose indicator turns acidic solution to green. True / False
Answer: False
In simple words: China rose tea turns dark pink in acid and green in a base.

Exam Tip: Remember: China rose turns acids magenta (dark pink) and bases green.

Name the Following

Question 1. Two natural indicators.
Answer: Litmus and turmeric
In simple words: Litmus from lichens and yellow turmeric powder are natural indicators.

Exam Tip: China rose petal extract is another common natural indicator.

Question 2. One artificial indicator
Answer: Phenolphthalein
In simple words: Phenolphthalein is a man-made chemical used to test acids and bases.

Exam Tip: Methyl orange is another well-known synthetic indicator.

Question 3. Two pollutants in the air which causes acid rain.
Answer: Sulphur dioxide and nitrogen dioxide
In simple words: Factory smoke containing sulphur dioxide and nitrogen dioxide creates acid rain.

Exam Tip: These gases dissolve in raindrops to form sulphuric acid and nitric acid.

Question 4. Two substances which can neutralize an ant’s bite.
Answer: Moist baking soda and calamine solution
In simple words: Rubbing baking soda paste or calamine lotion soothes painful ant bites.

Exam Tip: Ant venom contains formic acid, which these mild bases quickly neutralize.

Question 5. Two acids found in citrus fruits.
Answer: Citric acid and ascorbic acid
In simple words: Lemons and oranges contain tangy citric acid and vitamin C (ascorbic acid).

Exam Tip: Ascorbic acid is the chemical name for Vitamin C.

Define

Question 1. Indicators
Answer: Indicators are special chemical substances that display distinct color changes when added to acidic or basic solutions.
In simple words: An indicator changes its color to tell you if a liquid is an acid or a base.

Exam Tip: Explain that indicators are used safely because we cannot taste unknown laboratory chemicals.

Question 2. Neutral solution
Answer: A neutral solution is a liquid that is neither acidic nor alkaline and causes no color change on any indicator.
In simple words: A neutral liquid is completely balanced and does not act like an acid or a base.

Exam Tip: Pure water has a neutral pH value of 7.

Chapter 6: Physical and Chemical Change

Fill in the Blanks

Question 1. Changes that lead to the formation of new substances are called ________________
Answer: chemical changes
In simple words: A chemical change creates brand-new substances with different properties.

Exam Tip: Chemical changes are typically permanent and cannot be reversed easily.

Question 2. Melting of candle wax is a______________ change but its burning is a ______________ change.
Answer: physical, chemical
In simple words: Melting wax just changes solid to liquid, but burning the wick makes smoke and new gases.

Exam Tip: A burning candle demonstrates both physical change (wax melting) and chemical change (wax burning).

Question 3. Growth of a plant is a ____________ change while formation of clouds is a _____________ change.
Answer: chemical, physical
In simple words: A plant growing is an irreversible chemical process, but clouds forming from vapor is a physical change.

Exam Tip: Cloud formation is reversible through condensation and evaporation.

Question 4. A brown layer formed when an iron article is left exposed in air in an open area is called ___________
Answer: rust
In simple words: Damp air and oxygen combine on iron surfaces to create flaky brown rust.

Exam Tip: Rust is chemically different from elemental iron and weakens metal over time.

Question 5. Large crystals of pure substance are obtained by _____________
Answer: crystallization
In simple words: Crystallization lets pure solid crystals grow from a cooled saturated solution.

Exam Tip: Crystallization is a physical change used to purify substances like copper sulphate.

Question 6. The brown layer deposited on an iron nail dipped in copper sulphate solution is due to ______________
Answer: copper
In simple words: Iron displaces copper from the blue liquid, leaving reddish-brown copper on the nail.

Exam Tip: The solution turns from blue to light green because iron sulphate is formed.

Name the Following

Question 1. Write the chemical formula of lime water.
Answer: \( \text{Ca(OH)}_2 \)
In simple words: The chemical formula for lime water is written as Ca(OH)2.

Exam Tip: Calcium hydroxide is prepared by slaking quicklime (\(\text{CaO}\)) with water.

Question 2. Write the chemical name of Mg(OH)2
Answer: Magnesium hydroxide
In simple words: Mg(OH)2 is called magnesium hydroxide, commonly found in Milk of Magnesia.

Exam Tip: It is widely used as an antacid to relieve stomach acidity.

Question 3. Write the chemical name and formula of rust.
Answer: Hydrated iron(III) oxide, \( \text{Fe}_2\text{O}_3\cdot x\text{H}_2\text{O} \)
In simple words: Rust is chemically known as hydrated iron oxide.

Exam Tip: Writing either \( \text{Fe}_2\text{O}_3 \) or \( \text{Fe}_2\text{O}_3\cdot x\text{H}_2\text{O} \) is accepted for Class 7.

Question 4. Write the chemical name of blue vitriol.
Answer: Copper sulphate
In simple words: Blue vitriol is the common name for bright blue copper sulphate crystals.

Exam Tip: Its hydrated chemical formula is \( \text{CuSO}_4\cdot 5\text{H}_2\text{O} \).

Complete the Following Chemical Reactions

Question 1. Magnesium oxide (MgO) + water (H2O) → ______________
Answer: Magnesium hydroxide [\( \text{Mg(OH)}_2 \)]
In simple words: Burning magnesium ash mixes with water to form basic magnesium hydroxide.

Exam Tip: This solution turns red litmus paper blue, proving it is a base.

Question 2. Iron (Fe) +oxygen (O2 ) + water (H2O)→ ________________
Answer: Rust [\( \text{Fe}_2\text{O}_3\cdot x\text{H}_2\text{O} \)]
In simple words: Iron reacts with oxygen and moisture to produce flaky brown rust.

Exam Tip: Both oxygen and moisture must be present together for rusting to occur.

Question 3. Carbondioxide ( CO2) + Lime water [Ca(OH)2]→ _______ + _______
Answer: Calcium carbonate [\( \text{CaCO}_3 \)] + Water [\( \text{H}_2\text{O} \)]
In simple words: Carbon dioxide turns clear lime water milky because white calcium carbonate forms.

Exam Tip: Turning lime water milky is the standard test for identifying carbon dioxide gas.

Question 4. Copper sulphate + Iron → ______________ + _________________
Answer: Iron sulphate + Copper
In simple words: Iron takes the sulphate from blue copper sulphate, leaving green iron sulphate and pure copper metal.

Exam Tip: This is a displacement reaction where more reactive iron displaces less reactive copper.

Define

Question 1. Crystallization
Answer: Crystallization is a physical purification method in which solid crystals separate out from a hot saturated solution as it cools.
In simple words: Crystallization lets neat, pure crystals form when a hot saturated liquid cools down.

Exam Tip: Highlight that crystallization is a physical change because no new substance is made.

Question 2. Galvanization
Answer: Galvanization is the industrial application of a thin layer of zinc metal over iron or steel to shield it against rusting.
In simple words: Coating iron with zinc stops moisture and air from causing rust.

Exam Tip: Water pipes and car bodies are commonly galvanized to prolong their life.

Distinguish Between

Question 1. Physical change and chemical change
Answer: A physical change affects only the physical appearance, size, or state of a substance without forming anything new, and it is usually reversible (like melting butter). A chemical change rearranges atoms to create entirely new substances with new chemical properties, and it is typically permanent and irreversible (like rusting iron).
In simple words: Physical changes change shape or state reversibly, while chemical changes create brand-new substances permanently.

Exam Tip: Contrast reversibility and the formation of a new substance to score full marks.

Chapter 7: Weather, Climate and Adaptations of Animals to Climate

Fill in the Blanks

Question 1. ______________ is the measure of moisture in air.
Answer: Humidity
In simple words: Humidity tells us how much invisible water vapor is floating in the air.

Exam Tip: When humidity is high, sweat evaporates slowly and we feel sticky.

Question 2. The weather reports are prepared by the ___________ department of the government.
Answer: Meteorological
In simple words: The Meteorological Department studies the atmosphere and writes daily weather forecasts.

Exam Tip: This department uses satellite imagery, barometers, and rain gauges to forecast weather.

Question 3. The day today condition of the atmosphere is a place is called ____________ at that place.
Answer: weather
In simple words: Weather describes what the air outside is like on any given day.

Exam Tip: Weather changes quickly from day to day or even hour to hour.

Question 4. The maximum temperature of the day occurs in the ___________ while minimum temperature occurs in the ______________.
Answer: afternoon, early morning
In simple words: Days feel warmest in the afternoon and coldest around sunrise.

Exam Tip: Ground heating accumulates by afternoon, making it warmer than noon.

Question 5. Polar regions are situated near ___________ and tropical region is situated around the _______________.
Answer: the poles, equator
In simple words: Polar lands surround the North and South Poles, while tropics lie around Earth's equator.

Exam Tip: The equator receives direct overhead sunlight, making tropical areas warm year-round.

Question 6. Special features of an animal to live in its surrounding is called _______________
Answer: adaptation
In simple words: Useful body traits and habits that help an animal survive are called adaptations.

Exam Tip: Adaptations develop gradually over thousands of years through evolution.

Question 7. Penguins are good swimmer because their bodies are___________ and their feet have __________________.
Answer: streamlined, webs
In simple words: Sleek bodies and webbed paddle-like feet help penguins zoom through chilly water.

Exam Tip: Flippers and streamlined contours cut down water drag while swimming.

Question 8. All the changes in the weather are driven by the ______________
Answer: sun
In simple words: The sun's heat warms land and oceans unevenly, driving all winds and weather.

Exam Tip: Sunlight is the prime engine behind atmospheric pressure differences and storms.

Question 9. One of the important feature of tropical region is __________
Answer: hot and humid climate
In simple words: Tropical regions stay warm and receive generous rainfall throughout the year.

Exam Tip: Even in the coldest winter month, tropical temperatures rarely fall below 15 °C.

Question 10. The ___________ regions are very cold throughout the year.
Answer: polar
In simple words: Polar regions stay covered in ice and experience freezing cold weather all year.

Exam Tip: Temperatures can drop as low as -37 °C during polar winters.

Question 11. The temperature, humidity, rainfall and other factors are called _____________________ of the weather.
Answer: elements
In simple words: Temperature, moisture, rain, and wind are the basic elements of weather.

Exam Tip: Wind speed and atmospheric pressure are also key weather elements.

Question 12. The typical desert climate is ___________ and _____________.
Answer: hot, dry
In simple words: Deserts have high daytime temperatures and get very little rain.

Exam Tip: Sandy ground heats up fast during the day and cools quickly at night.

Question 13. The climate of the north-east of India is __________________
Answer: wet
In simple words: North-eastern India experiences high rainfall for most of the year, so it has a wet climate.

Exam Tip: Mawsynram and Cherrapunji in Meghalaya receive some of the highest rainfall on Earth.

Question 14. _____________ is a means which is adapted by some birds to escape the harsh, cold conditions.
Answer: Migration
In simple words: Migration means flying to warmer southern lands to escape freezing winters.

Exam Tip: The Siberian crane travels thousands of kilometers to Bharatpur in Rajasthan every winter.

Name the Following

Question 1. An instrument used to measure rainfall.
Answer: Rain gauge
In simple words: A rain gauge is a measuring cylinder topped with a funnel to record rainfall.

Exam Tip: Rainfall depth is measured in millimeters.

Question 2. The thermometer used to record maximum and minimum temperature.
Answer: Maximum-minimum thermometer
In simple words: This U-shaped thermometer tracks the highest and lowest daily temperatures.

Exam Tip: It is also known as Six's thermometer.

Question 3. Two animals living in polar regions.
Answer: Polar bear and penguin
In simple words: Polar bears live in the Arctic, and penguins live in the Antarctic.

Exam Tip: Arctic foxes, seals, and musk oxen also inhabit polar zones.

Question 4. Two animals living in tropical regions.
Answer: Red-eyed tree frog and lion-tailed macaque
In simple words: Tree frogs and monkeys thrive in warm, leafy rainforests.

Exam Tip: Tropical rainforests support the highest variety of animal life on the planet.

Question 5. Two animals with ability to camouflage with the surroundings.
Answer: Chameleon and stick insect
In simple words: Chameleons and stick insects blend into leaves to hide from predators.

Exam Tip: Polar bears also camouflage naturally against white ice and snow.

Choose the Correct Answer

Question 1. Long tailed macaque is also known as (Beard ape / Monkey)
Answer: Beard ape
In simple words: The lion-tailed macaque has a silvery-white mane around its face like a beard.

Exam Tip: This monkey lives in the Western Ghats rainforests and feeds mostly on fruits and insects.

Question 2. (Weather / Climate) changes frequently.
Answer: Weather
In simple words: Weather can switch from sunny to rainy within hours.

Exam Tip: Climate represents an average over roughly 25 years and stays stable.

Question 3. Tusks of elephants are modified (teeth/bones)
Answer: teeth
In simple words: Elephant tusks are actually overgrown incisor teeth.

Exam Tip: Elephants use their tusks to tear bark off trees and fight enemies.

Write True or False

Question 1. Mammals, many types of fish and insects are also known to migrate seasonally. ________
Answer: True
In simple words: Not just birds, but whales, salmon fish, and butterflies also migrate.

Exam Tip: Monarch butterflies fly thousands of miles south every winter.

Question 2. Polar regions doesn’t see the sun for six months. _____________
Answer: True
In simple words: At the poles, the sun stays set for six months and stays risen for the next six months.

Exam Tip: This extreme day-night cycle is caused by Earth's tilted rotational axis.

Question 3. Days are longer than nights in winter. ___________
Answer: False
In simple words: Winter has short daylight hours and long, chilly nights.

Exam Tip: Summer features longer days and shorter nights.

Define the Following

Question. > Weather
Answer: Weather is the day-to-day state of the atmosphere at a particular location concerning temperature, air moisture, rain, and wind speed.
In simple words: Weather tells us what the atmosphere is doing right now at a specific place.

Exam Tip: Name temperature, humidity, rainfall, and wind as key elements of weather.

Question. > Climate
Answer: Climate is the long-term average pattern of weather recorded at a place over a substantial period, typically about 25 years.
In simple words: Climate is the usual weather pattern seen over decades in an area.

Exam Tip: The standard period used by meteorologists to calculate climate is 25 years.

Question. > Adaptation.
Answer: Adaptation is any special physical trait or behavioral habit that enables a living organism to survive and reproduce in its natural habitat.
In simple words: Adaptations are special body features that help animals thrive in their homes.

Exam Tip: Adaptations can be structural (like a camel's hump) or behavioral (like migration).

Lesson 8: Winds, Storms and Cyclones

Fill in the Blanks

Question 1. _____________________ around us exerts pressure.
Answer: Air
In simple words: The thick ocean of air around us presses down on everything.

Exam Tip: Atmospheric pressure is demonstrated by crushing tin cans when steam condenses inside.

Question 2. Difference of temperature between two regions sets ___________ in air.
Answer: convection currents
In simple words: Uneven heating makes warm air rise and cooler air rush in, creating breezes.

Exam Tip: Convection currents are the primary engine for wind flow across regions.

Question 3. Increased wind speed is accompanied by __________ air pressure.
Answer: reduced (lower)
In simple words: Fast-moving air creates low air pressure around it.

Exam Tip: High-speed winds blow over roofs and can lift them off due to reduced pressure above.

Question 4. Air moves from the region where the air pressure is _________ to the region where the pressure is _______________.
Answer: high, low
In simple words: Air always rushes out of high-pressure zones into low-pressure pockets.

Exam Tip: The greater the pressure difference, the faster the wind blows.

Question 5. Air _______________on heating and __________ on cooling.
Answer: expands, contracts
In simple words: Heating makes air swell and take up more room, while cooling shrinks it.

Exam Tip: Hot air expands, becomes lighter (less dense), and floats upward.

Question 6. The warm air is ____________ than the cold air.
Answer: lighter
In simple words: Warm air weighs less than chilly air, so smoke floats up into the sky.

Exam Tip: This density difference explains why warm air always rises above cooler air.

Question 7. Uneven heating on the earth is the main cause of ______________
Answer: wind currents
In simple words: The sun warms the equator more than the poles, creating global winds.

Exam Tip: Earth's rotation also shifts the path of these global wind currents.

Question 8. Winds carrying ______________ bring rain.
Answer: water vapour
In simple words: Sea winds laden with water vapor create dark clouds that drop rain.

Exam Tip: Monsoon winds travel over vast oceans, picking up moisture along the way.

Question 9. The word monsoon is derived from the Arabic word ___________ which means season.
Answer: 'mausam'
In simple words: "Monsoon" comes from the Arabic word "mausam", meaning season.

Exam Tip: Monsoon winds blow in opposite directions between summer and winter.

Question 10. The monsoon winds carry ____________ and it rains.
Answer: water (moisture)
In simple words: Wet sea winds carry moisture inland, bringing precious rain to farm crops.

Exam Tip: Summer monsoons carry water from the southwest Indian Ocean over the Indian subcontinent.

Question 11. Falling water droplets along with rising air create lightning and sound and is known as _______________
Answer: thunderstorm
In simple words: Falling rain combined with rising air currents makes flashes of lightning and loud thunder.

Exam Tip: Thunderstorms develop frequently in hot, humid tropical areas like India.

Question 12. High speed winds and air pressure difference can cause ________________________
Answer: cyclones
In simple words: Wild differences in air pressure spawn giant spinning storms called cyclones.

Exam Tip: Cyclones produce heavy rain, storm surges, and destructive gale-force winds.

Question 13. The calm area in the centre of a cyclone is called __________
Answer: eye
In simple words: The peaceful, cloud-free center of a spinning cyclone is called its eye.

Exam Tip: The eye of a cyclone has very low pressure, light winds, and no clouds.

Question 14. A cyclone is called a _______________ in the American continent and _____________in Japan and Philippines.
Answer: hurricane, typhoon
In simple words: Cyclones are called hurricanes in the Americas and typhoons in East Asia.

Exam Tip: All three are regional names for tropical cyclones formed over warm oceans.

Name the Following

Question 1. A dark funnel shaped cloud that reaches from the sky to the ground.
Answer: Tornado
In simple words: A tornado is a spinning funnel of dark air sucking up debris from the ground.

Exam Tip: Wind speeds inside a violent tornado can exceed 300 km/h.

Question 2. The instrument that measures the wind speed
Answer: Anemometer
In simple words: An anemometer has spinning cups that measure how fast the wind blows.

Exam Tip: Wind direction, in contrast, is measured using a wind vane.

Question 3. Two modern technologies that help us to monitor cyclones.
Answer: Satellites and weather radars
In simple words: Space satellites and radar stations help scientists track incoming storms in advance.

Exam Tip: Satellites issue a Cyclone Alert 48 hours before a storm hits the coast.

Question 4. The coastline of India that is more vulnerable to cyclones.
Answer: Eastern coastline
In simple words: India's east coast along the Bay of Bengal suffers from more frequent cyclones.

Exam Tip: States like Odisha, Andhra Pradesh, and Tamil Nadu face frequent Bay of Bengal cyclones.

Define the Following

Question 1. Cyclone
Answer: A cyclone is a huge, violently rotating weather system featuring a very low-pressure center surrounded by high-speed swirling winds and torrential rains.
In simple words: A cyclone is a giant spinning ocean storm with howling winds and heavy rain.

Exam Tip: Heat released when water vapor condenses into rain fuels the cyclone's power.

Question 2. Tornado
Answer: A tornado is a violent, spinning funnel-shaped cloud that stretches downward from a thunderstorm all the way to touch the ground.
In simple words: A tornado is a dark twisting wind funnel that destroys things on the ground.

Exam Tip: Most tornadoes have a diameter ranging from a few meters to a kilometer.

Question 3. Thunderstorm
Answer: A thunderstorm is an intense local storm produced by warm, moist rising air, characterized by heavy rain, flashing lightning, and loud thunder.
In simple words: A thunderstorm is a stormy weather event filled with bright lightning flashes, loud thunder, and pouring rain.

Exam Tip: Never take shelter under an isolated tall tree or hold metal umbrellas during a thunderstorm.

Choose the Correct Answer

Question 1. In India, monsoon wind blows in south west direction in (summer/winter).
Answer: summer
In simple words: Warm southwest monsoon winds bring rainy weather across India during summer months.

Exam Tip: Land heats up faster than the Indian Ocean in summer, pulling in southwest winds.

Question 2. In winter, the direction of wind is from (land to ocean/ocean to land).
Answer: land to ocean
In simple words: Cold winter winds blow outward from the cooler land toward the warmer sea.

Exam Tip: Because they blow from dry land, winter monsoon winds bring dry weather to most of India.

Question 3. A cyclone watch is issued ( 24/48 ) hours in advance of any expected storm.
Answer: 48
In simple words: A Cyclone Alert or watch is broadcast 48 hours before an expected storm arrives.

Exam Tip: A Cyclone Warning is issued 24 hours in advance, while a Cyclone Alert is issued 48 hours ahead.

Question 4. (Thunderstorms/tornadoes) are frequent in India.
Answer: Thunderstorms
In simple words: Thunderstorms happen frequently in warm tropical India, whereas tornadoes are quite rare.

Exam Tip: Warm, humid conditions across India promote the frequent rising of moist air that fuels thunderstorms.