SOLUTIONS CHAPTER 1 Food: Where does it come from?

1. Do you find that all living beings need the same kind of food?

Answer:  

No, all living beings do not need the same kind of food. Different living beings have different nutritional requirements based on their body structure and functions. For example, herbivores mainly eat plants, carnivores mainly eat other animals, and omnivores eat both plants and animals.

2. Name five plants and their parts that we eat.

Answer:

Some examples of plants and their edible parts are:

Carrot (root)

Tomato (fruit)

Spinach (leaves)

Broccoli (flower)

Potato (tuber)

3. Match the items given in Column A with that in Column B.

Answer:

Column A .. Column B     

(a)......................(4)

(b)......................(3)

(c)......................(1)

(d)......................(2)

4. Fill up the blanks with the words given:

Answer:

(a) Tiger is a carnivore because it eats only meat.  

(b) Deer eats only plant products and so, is called herbivore.  

(c) Parrot eats only plant products.  

(d) The milk that we drink, which comes from cows, buffaloes and goats is an animal product.  

(e) We get sugar from sugarcane.  

5. What are ingredients?

Answer:

Ingredients are the components or substances that are used to make a product, such as food, cosmetics, medicines, or cleaning products.  

For example: -Rice, sugar milk dry fruits and essence are needed to make kheer.

These components are combined in specific proportions to create a desired result or taste. 

6. Write the main functions of food.

Answer: Food provides us energy for various activities.

Food protects our body from diseases and keeps us fit and healthy.

7. Name the food materials obtained from the plant and animals?

Answer:

Sugar, Rice, Wheat Vegetables etc., are obtained from plants.

Milk, egg, meat, cheese, honey etc. are obtained from animals.

8. Define Herbivorous, carnivorous and omnivorous.

Answer:

Herbivorous refers to animals that primarily eat plants as their main source of food. Examples of herbivorous animals include cows, deer, rabbits, and horses.

Carnivorous refers to animals that primarily eat meat as their main source of food. Examples of carnivorous animals include lions, tigers, wolves, and sharks.

Omnivorous refers to animals that eat both plants and animals as part of their diet. Examples of omnivorous animals include humans, bears, Crow, and pigs.

9. Green plants are also known as primary producers why?

Answer:

Green plants are known as primary producers because they are capable of producing organic compounds through photosynthesis, using sunlight, carbon dioxide, and water.  

This process is the foundation of the food chain and provides energy for all other living organisms in the ecosystem.

Primary producers are the first trophic level in the food chain and form the basis of all life on Earth.

Q1. What are ingredients?

Answer:

Ingredients are the components or substances that are used to make a product, such as food, cosmetics, medicines, or cleaning products.  

For example: -Rice, sugar milk dry fruits and essence are needed to make kheer.

These components are combined in specific proportions to create a desired result or taste. 

Q2. Write the main functions of food.

Answer: Food provides us energy for various activities.

Food protects our body from diseases and keeps us fit and healthy.

Q3. Name the food materials obtained from the plant and animals?

Answer:

Sugar, Rice, Wheat Vegetables etc., are obtained from plants.

Milk, egg, meat, cheese, honey etc. are obtained from animals.

Q4. Define Herbivorous, carnivorous and omnivorous.

Answer:

Herbivorous refers to animals that primarily eat plants as their main source of food. Examples of herbivorous animals include cows, deer, rabbits, and horses.

Carnivorous refers to animals that primarily eat meat as their main source of food. Examples of carnivorous animals include lions, tigers, wolves, and sharks.

Omnivorous refers to animals that eat both plants and animals as part of their diet. Examples of omnivorous animals include humans, bears, Crow, and pigs.

Q5. Green plants are also known as primary producers why?

Answer:

Green plants are known as primary producers because they are capable of producing organic compounds through photosynthesis, using sunlight, carbon dioxide, and water.  

This process is the foundation of the food chain and provides energy for all other living organisms in the ecosystem.

Primary producers are the first trophic level in the food chain and form the basis of all life on Earth.

1. Name the major nutrients in our food.

Answer:

The major nutrients in our food are:  

(1) carbohydrates- are Energy provider.

(2) fats-Provides more energy, but act as reserved energy provider.  

(3) proteins- helps in body building and repair of tissues.

(4) vitamins- Vitamins help in protecting our body against diseases.  

(5) minerals- needed by our body in small amounts for proper growth of body and to maintain good health.  

(6) dietary fibers- also known as roughage, no calorific value, needed for proper functions.   

(7) water- has no calorific value but helps our body to absorb nutrients from food. It also helps in throwing out some wastes from body as urine and sweat.  

2. Name the following:

Answer:

(a) The nutrients which mainly give energy to our body are ___carbohydrates (and fats reserved energy)____.  

(b) The nutrients that are needed for the growth and maintenance of our body are___proteins___.  

(c) A vitamin required for maintaining good eyesight is___Vitamin A___.  

(d) A mineral that is required for keeping our bones healthy is___Calcium___.  

3. Name two foods each rich in:

Answer:

(a) Fats 

(a) Foods rich in fats: Avocado, nuts (such as almonds, walnuts, and cashews)  

(b) Starch  

(b) Foods rich in starch: Potatoes, rice  

(c) Dietary fibre  

(c) Foods rich in dietary fiber: Oatmeal, broccoli, green leafy vegetables.

(d) Protein

(d) Foods rich in protein: Chicken, eggs, dal, Milk.  

4. Tick (√) the statements that are correct.

Answer:

(a) By eating rice alone, we can fulfill nutritional requirement of our body. (False)  

(b) Deficiency diseases can be prevented by eating a balanced diet. (True )  

(c) Balanced diet for the body should contain a variety of food items. (True )  

(d) Meat alone is sufficient to provide all nutrients to the body. (False )  

5. Fill in the blanks.

Answer:

(a) ___Rickets___is caused by deficiency of Vitamin D.  

(b) Deficiency of ___thiamine (Vitamin B1)____ causes a disease known as beri-beri.  

(c) Deficiency of Vitamin C causes a disease known as ___scurvy___.  

(d) Night blindness is caused due to deficiency of ___Vitamin A___ in our food.  

6. What do you mean by deficiency diseases

Answer:

Deficiency of one or more nutrients can cause diseases or disorders in our body. Diseases that occur due to lack of nutrients over a long period are called deficiency diseases.

Important Questions

1. Classify the following fibres as natural or synthetic: nylon, wool, cotton, silk, polyester,

Answer:

Natural fibers: wool, cotton, silk, jute  

Synthetic fibers: nylon, polyester

2. State whether the following statements are true or false:

Answer:

a) Yarn is made from fibres (True )   

b) Spinning is a process of making fibres (True )

c) Jute is the outer covering of coconut (False )

d) The process of removing seed from cotton is called ginning (True )

e) Weaving of yarn makes a piece of fabric(True )

f) Silk fibre is obtained from the stem of a plant (False )

g) Polyester is a natural fibre (False )

3. Fill in the blanks:

Answer:

a) Plant fibres are obtained from Jute and cotton.  

b) Animal fibres are silk and wool.

4. From which parts of the plant cotton and jute are obtained?

Answer:

Cotton is obtained from fruits of the cotton plant and jute is obtained from the stem of the jute plant.

5. Name two items that are made from coconut fibre.

Answer:

Clothing - T-shirts, shirts, pants, dresses, skirts, etc.

Medical supplies - Bandages, swabs, cotton balls, etc.  

Bags - Tote bags, backpacks, etc

6. Explain the process of making yarn from fibre.

Answer:

The process of making yarn from fibres is called spinning. In this process, fibres from a mass of cotton wool are drawn out and twisted. This brings the fibres together to form a yarn.  

A simple device used for spinning is a hand spindle, also called takli.

Another hand operated device used for spinning is charkha.

Spinning of yarn on a large scale is done with the help of spinning machines. After spinning, yarns are used for making fabrics.  

Q1. Define natural and synthetic fiber and give example.

Answer:

Natural fibers: 

The fibers that are obtained from plants and animals are called natural fibers.   

wool, cotton, silk, jute  

Synthetic fibers:

The fibers which are not obtained from plant or animal sources are called synthetic fibers.

nylon, polyester and acrylic.

1. Name five objects which can be made from wood.

Answer:  

The names of the five objects are:

Table

Chair

Doors

Boat

Spoon

2. Select those objects from the following which shine: Glass bowl, plastic toy, spoon, cotton

Objects those shine are:

Answer:

Glass bowl

steel spoon

3. Match the objects given below with the materials from which they could be made.

Answer:

Book...............Paper

Tumbler..........Glass and plastic

Chair...............Wood and plastic

Toy..................Plastic and wood

Shoes.............Leather

4. State whether the statements given below are True or False

Answer:

(i) Stone is transparent, while glass is opaque (False )

(ii) A notebook has lustre while eraser does not (False )

(iii) Chalk dissolves in water (False )

(iv) A piece of wood floats on water (True )

(v) Sugar does not dissolve in water (False )

(vi) Oil mixes with water (False ) 

(vii) Sand settles down in water (True )

(viii) Vinegar dissolves in water (True )  

5. Given below are the names of some objects and materials: Water, basket ball, orange, sugar, globe, apple and earthen pitcher Group them as:

Answer:

(a) Round shaped and other shapes  

Round shaped objects are

Basketball, orange, globe, apple and earthen pitcher

Other Shapes objects are

Water (takes the shape of container), sugar  

(b) Eatables and non eatables  

Eatables  

Water, orange, sugar, apple  

Non eatables

Basketball,  globe, earthen pitcher  

6. List all items known to you that float on water. Check and see if they will float on an oil

or Kerosene My list of Item is:

Answer:

My list of Item is:

Apple....float on water and sink in oil or kerosene.

Plastic bottle.... float on water and sink in oil or kerosene.

Tennis ball.... float on water and sink in oil or kerosene.

Thermacol....float on water and float on oil or kerosene

wood.... float on water and float on oil or kerosene

Bamboo.... float on water and float on oil or kerosene

Cork......float on water and float on oil or kerosene

7. Find the odd one out from the following:

Answer:

a) Chair, Bed, Table, Baby, Cupboard  

Baby

b) Rose, Jasmine, Boat, Marigold, Lotus  

Boat

c) Aluminium, Iron, Copper, Silver, Sand.

Sand

d) Sugar, Salt, Sand, Copper sulphate  

Sand

Q1. What are soluble and insoluble material?

Answer:

Soluble material are those which completely disappear or get dissolved in water. We say that these substances are soluble in water.

e.g. Ink, juice, glucose powder, salt

Substances that do not mix with water and do not disappear even after we stir for a long time. These substances are called insoluble material.  

e.g., chalk, scale, pencil, lunchbox.

Q2. Define transparent, translucent and opaque objects with example?

Answer:

The objects through which we can see clearly are called transparent objects.

Eg., Glass, water, air  

The objects through which we can see but not clearly are called translucent objects.

Eg., Colored glass, Scale(ruler)

The objects through which we cannot see completely, they do not allow light to pass through them are called opaque objects.

Eg, brick wall, notebook, hand.

Q3. Give different properties of material.

Answer:

The various properties of material are:

Appearance: How they look like?

Hardness: -How do we feel when we touch them?

Solubility-What happens when they are immersed in water?

Transparency-Can we see through them? etc.

1. To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?  

Answer:

Yes, this change be reversed, the length of dress can be changed back to its earlier form by unfolding it.

2. You accidentally dropped your favourite toy and broke it. This is a change you did not want. Can this change be reversed?

Answer:  

No this change cannot be reversed, as the broken toy will have cracks even after fixing it.  

3. Some changes are listed in the following table. For each change, write in the blank column,

whether the change can be reversed or not.  

Answer:   

The sawing of a piece of wood.....No

The melting of ice candy.….........Yes

Dissolving sugar in water.......…..Yes

The cooking of food................…..No

The ripening so a mango..............No

Souring of milk.............................No

4. A drawing sheet changes when you draw a picture on it. Can you reverse this change?

Answer:

Yes, it can be reversed if drawn with a soft pencil, but if the picture is drawn with pen or color, it the change cannot be reversed.  

5. Give examples to explain the difference between changes that can or cannot be reversed.

Answer:

Changes that can be undone or reversed back to their original state or condition are called reversible changes. e.g.  

Melting an ice cube: When you apply heat to an ice cube, it melts and turns into liquid water. However, if you remove the heat, the liquid water will freeze back into solid ice.

Inflating a balloon: When you inflate a balloon with air, it expands and becomes bigger. However, if you release the air from the balloon, it will shrink back to its original size.

Dyeing your hair: If you dye your hair a different color, you can always dye it back to its original color or a different color.

Folding of sleaves of shirt: This is example of reversible change because we can unfold the sleaves of a shirt.

Changes that cannot be undone or reversed back to their original state or condition are called reversible changes. e.g.  

Burning a piece of paper: When you burn a piece of paper, it turns into ash and cannot be turned back into paper.

Cooking an egg: When you cook an egg, it changes from a liquid to a solid state and cannot be turned back into a liquid state.

Aging: As we age, our bodies go through changes that cannot be reversed. We cannot turn back time and become younger.

Tearing paper: when we tear a paper sheet, we cannot fix it back as original.

6. A thick coating of a paste of Plaster of Paris (POP) is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilized. Can the change in POP be reversed?

Answer:

No, the change in Plaster of Paris (POP) cannot be reversed. When water is added to POP, it undergoes a chemical reaction called hydration. This chemical reaction is irreversible, which means that once the POP has hardened, it cannot be returned to its original state.  

7. A bag of cement lying in the open gets wet due to rain during the night. The next day the sun shines brightly. Do you think the changes, which have occurred in the cement, could be reversed?  

Answer:

When cement gets wet, the water triggers a chemical reaction called hydration, which causes the cement to harden and solidify.  

This reaction is irreversible, which means that once the cement has hardened, it cannot be returned to its original state.

Important Questions

1. Correct the following statements and rewrite them in your notebook.

• (a) Stem absorbs water and minerals from the soil.

Corrected statement:

(a) Roots absorbs water and minerals from the soil.  

• (b) Leaves hold the plant upright.

Corrected statement: 

(b) Stem hold the plant upright.

• (c) Roots conduct water to the leaves.  

Corrected statement:

(c) Stem conduct water to the leaves.  

• (d) The number of petals and stamens in a flower is always equal.  

Corrected statement:

(d) The number of petals and stamens in a flower is usually equal.  

• (e) If the sepals of a flower are joined together, its petals are also joined together.

Corrected statement: 

(e) If the sepals of a flower are joined together, its petals are not necessarily joined together.

• (f) If the petals of a flower are joined together, then the pistil is joined to the petal. 

Corrected statement:

(f) If the petals of a flower are joined together, then the pistil is not necessarily joined to the petal.

2. Draw (a) a leaf, (b) a taproot and (c) a flower, you have studied for Table 7.3  

Answer:

Sketch

3. Can you find a plant in your house or in your neighborhood, which has a long but weak stem? Write its name. In which category will you place it?

Answer:

Yes, Its name is snake guard, its category is climber.

4. What is the function of a stem?

Answer:

The main functions of stem are as under:

It holds the plant upright.

Stem holds the leaves and branches of the plant.

Stem transports water from roots to different parts of the plant.

Stem transports food from leaves to different parts of the plant.

Stem bears, leaves, flowers and fruits.

In some plants stem store food for the plant e.g. potato.

In some plants system also help in photosynthesis e.g., Cactus.

5. Which of the following leaves have reticulate venation?

Wheat, tulsi, maize, grass, coriander (dhania), China rose.  

Answer:

Tulsi, maize, coriander (dhania), China rose has reticulate venation and Wheat, and grass, has parallel venation.

6. If a plant has fibrous root, what type of venation do its leaves have?

Answer:

If a plant has fibrous root, it will have parallel venation and if it has tap root, it will have reticulate venation.

7. If a plant has leaves with reticulate venation, what kind of roots will it have?

Answer:

If a plant has leaves with reticulate venation, it will have tap roots.

8. Is it possible for you to find out whether a plant has taproot or fibrous roots by looking at the impression of its leaf on a sheet of paper?

Answer:

Yes, it is possible, If the leaf shows parallel venation the root type will be fibrous root.

If the leaf impression is reticulate venation the root type will be tap root.

It is an amazing fact that leaf venation and type of root is related to each other.

9. What are the parts of a flower?

Answer:

The parts of the flower are as:

• Petals: It is the color full part of the plant, often fragrant that attract pollinators like bees and butterflies.
• Sepals:  are leaf-like in appearance, mainly green in colour and usually at the base that provide support.
• Stamens: Stamen is the male reproductive organ of a flower. It consists of two main parts: the anther and the filament.  
• Pistil: The pistil is the female reproductive organ of a flower. located in the center of the flower, It is composed of three main parts: the stigma, style, and ovary.  

10. From the following plants, which of them have flowers?

Grass, maize, wheat, chilli, tomato, tulsi, peepal, shisham, banyan, mango, jamun, guava, pomegranate, papaya, banana, lemon, sugarcane, potato, groundnut  

Answer:  

All of them have flowers, but grass and Tulsi have very small often unnoticed.

11. Name the part of plant which produces food. Name the process.

Answer:

Leaves prepare their food in the presence of sunlight and a green coloured substance (chlorophyll) present in them. For this, they also use water and carbon dioxide. This process is called photosynthesis.  

Oxygen is given out in this process. The food(glucose) prepared by leaves ultimately gets stored in different parts of plant.  

12. In which part of a flower, you will find the ovary?

Answer:

The central part of the flower is composed of three main parts: the stigma, style, and ovary. We can find it here.

The ovary is a part of the female reproductive structure of a flower and is typically located at the base of the pistil.  

13. Name two plants in which one has joined sepals and the other has separate sepals.

Answer:

Joined sepals are seen in:

Hibiscus, datura, cotton, tomato  

Separate sepals are seen in:

mustard, lotus, lily, jasmine, rose.  

Important Questions

1. Fill in the blanks:

Answer:

(a) Joints of the bones help in the —Movement—— of the body.  

(b) A combination of bones and cartilages forms the __skeleton__ of the body.  

(c) The bones at the elbow are joined by a __hinge__ joint.  

(d) The contraction of the __muscles__ pulls the bones during movement.  

2. Indicate true (T) and false (F) among the following sentences.

Answer:

(a) The movement and locomotion of all animals is exactly the same...… (False)  

(b) The cartilages are harder than bones...… (False )  

(c) The finger bones do not have joints...… (False )  

(d) The fore arm has two bones...… (False )  

(e) Cockroaches have an outer skeleton. ...… (True )  

3. Match the items in Column I with one or more items of Column II.

Answer:

Upper jaw---Is an immovable joint.

Fish-----------have fins on the body, have streamline body.

Ribs-----------protect the heart.

Snail-----------has an outer skeleton. shows very few movement.

cockroach----can fly in the air, has an outer skeleton.

4. Answer the following:

Answer:

(a) What is a ball and socket joint?  

A ball and socket joint is a type of joint in which a ball-shaped surface of one bone fits into a socket-shaped surface of another bone, allowing a wide range of motion in multiple directions. This type of joint is found in the human body in the hip joint and the shoulder joint.  

(b) Which of the skull bones are movable?  

Most of the bones in the skull are fused together and immovable, with the exception of the mandible (lower jawbone)  

(c) Why can our elbow not move backwards?  

The elbow joint is a hinge joint, which means that it allows movement in one direction only.  

A1. Name different types of joints and where are they present?

Answer:

Skull, upper jaw ------- -----immovable joint

Neck              ------- --------Pivot joint

Elbow, Knee      ------- -----Hinge joint

Shoulder, hip ------- --------Ball and socket joint.

A2. What do you understand from streamline body?

Answer:

The head and tail of the fish are smaller than the middle portion of the body – the body tapers at both ends. This body shape is called streamlined.  

A3. Define Joints, Pivotal Joint, skeleton, rib cage,

Answer:

We are able to bend or rotate our body in places where two parts of our body seem to be joined together — like elbow, shoulder or neck. These movable places are called joints.

Pivotal Joint: The joint where our neck joins the head is a pivotal joint. It allows us to bend our head forward and backward and turn the head to our right or left.  

Skeleton: is the framework of bones and cartilage that supports and protects the body's internal organs, provides a surface for muscle attachment, and allows for movement. The adult human skeleton consists of 206 bones  

Carpels:  The carpals are a group of eight small bones that make up the wrist joint in humans. The carpals are arranged in two rows, with four bones in each row.  

Rib cage: Ribs are curiously bent. They join the chest bone and the backbone together to form a box. This is called the rib cage. There are 12 ribs on each side of chest. Some important internal parts of our body lie protected inside this cage.  

A4. What do you mean by-backbone, cartilage? .

The backbone, also known as the spinal column or vertebral column, is a flexible and strong structure that runs from the base of the skull to the pelvis. It is made up of 33 individual vertebrae that are separated by intervertebral discs, which act as shock absorbers.  

Some additional parts of the skeleton that are not as hard as the bones and which can be bent. These are called cartilage .

A5. How does earth worm move give a short note?

Earthworms move by alternate extension and contraction of the body using muscles. Tiny bristles on the underside of the body help in gripping the ground.  

A6. Write a short note on movement of snake. Does it move in a straight line?

The snake’s body curves into many loops. Each loop of the snake gives it a forward push by pressing against the ground. Since its long body makes many loops and each loop gives it this push, the snake moves forward very fast and not in a Straightline.  

A7. What is skeleton and how do we move bones?

 Bones and cartilage form the skeleton of the human body. It gives the frame and shape to the body and helps in movement.  

The bones are moved by alternate contractions and relaxations of two sets of muscles.  

A8. How do snail move and bird fly?

Snails move with the help of a muscular foot.  

Strong muscles and light bones work together to help the birds fly. They fly by flapping their wings.  

1. What is a habitat?

Answer:

The surroundings where plants and animals live naturally, is called their habitat. Several kinds of plants and animals may share the same habitat.

The living organisms (both plant and animas) living in a habitat are called its biotic factors.

The various non-living things such as rocks, soil, air, sunlight and water in a habitat are its abiotic components.

2. How are cactus adapted to survive in a desert?

Answer:

Deset plants show a distinctive adaptation Desert plants lose very little water through transpiration.  

The leaves of cactus are either absent, very small, or they are in the form of spines. This helps in reducing loss of water from the leaves through transpiration.  

Cactus have adapted to survive in following ways-

Photosynthesis in Catus is usually carried out by the stems. The stem is also covered with a thick waxy layer, this helps to retain water in the tissues of cacti.  

Cactus have roots that go very deep into the soil for absorbing water.  

3. Fill up the blanks.

Answer:

(a) The presence of specific features, which enable a plant or an animal to live in a particular habitat, is called adaptation.  

(b) The habitats of the plants and animals that live on land are called terrestial habitat.  

(c) The habitats of plants and animals that live in water are called aquatic habitat.  

(d) Soil, water and air are the abiotic factors of a habitat.  

(e) Changes in our surroundings that make us respond to them, are called stimuli.  

4. Which of the things in the following list are nonliving? Plough, Mushroom, Sewing machine, Radio,

Answer:

Nonliving things are- Plough, Mushroom, Sewing machine, Radio, Boat, Water  

Living things are- hyacinth, Earthworm.  

5. Give an example of a non-living thing, which shows any two characteristics of living things.

One example could be Cloud, because cloud grows in size and cloud moves from one place to another.

Answer:

Other example could be Flame, because flame grows in size when fuel is added, and it responds to stimuli as it changes it shape when air is blown on it.

6. Which of the non-living things listed below, were once part of a living thing? Butter, Leather, Soil, Wool, Electric bulb, cooking oil, Salt, Apple, Rubber.

Answer:

Butter, Leather, Wool, Cooking oil, Salt, Apple, Rubber are nonliving things which were part of living thing once.

7. List the common characteristics of the living things.

Answer:

Some common characteristics of living things are under:

1. Growth-They change their size with time.
2. Movement-They move from one place to another.
3. Reproduction-The give birth to their own kind.
4. Respiration-They exchange gases from environment.
5. Response to stimuli-They respond to changes in their environment. 
6. Excretion-They expel waste products from their body.

8. Explain, why speed is important for survival in the grasslands for animals that live there.

(Hint: There are few trees or places for animals to hide in grasslands habitats.)

Answer

The grass lands have fever trees and places for animals to hide or camoflage they get easily spotted by predators.

Grassland animals have to save themselves from the strong predators like lion and cheetah, the speed of the deer and other grassland animal is the only way which helps them to run away from the predators and save their life.

A1. What are different types of habitats, give examples?

Answer:

Different types of habitats are as under -

1. Terrestrial Habitat: Terrestrial habitats are the natural environments found on land.  

Terrestrial habitats are characterized by a variety of physical and climatic conditions, such as temperature, rainfall, soil type, altitude, and topography as under.   

  a) Dessert- These areas receive very less rainfall like Sahara, Kalahari and thar. temperate in summers reaches up to 45 degrees. Annual rainfall is less than 25 cm.

Suitable plants- cactus, Joshua tree, opuntia, aloe vera etc.

Suitable animals- Camel, Rattle snake, lizard, rats, scorpion etc.

  b) Mountain and polar regions-They are polar regions arctic and Antarctica and tall mountains; climate is very cold up to -88 degrees. Heavy snow falls in winters.

Suitable plants-Juniper, cedar, apple tree willow etc.

Suitable animals- polar bear, penguin, seal, walrus, snow leopard, yak, mountain goat  etc.

  c) Grasslands-Regions dominated by grasses, not too many trees there, temperature 20 degrees to 30 degrees and annual rainfall varies between 50cm and 90cm.

Suitable plants-purple needle grass, wild oats, foxtail, rye grass, buffalo grass, golden rods sunflower etc.

Suitable animals-Giraffe, zebra, iron, elephant, gazelle etc.

2. Aquatic Habitat: An aquatic habitat refers to the natural environment where water-dwelling organisms, including animals, plants, and microorganisms, live and interact with each other.  

 Aquatic habitats can be divided into two main categories: freshwater and marine habitats.   

  a) Marine: Marine habitats include   oceans, seas, and coral reefs.  

Suitable plants-sea grass, kelp, seaweed, algae etc.

Suitable animals-Whales, dolphins, sharks, octopus, sea lion etc.

  b) Fresh water: freshwater habitats include rivers, lakes, streams, and wetlands,  

Suitable plants- Walet lily, lotus, duck weeks, cattails, musk grass.

Suitable animals-Fish, frogs, turtle, otters ducks, swans, water snakes etc,

A2. What is germination? how can you say life depends on abiotic factors?

Answer:

When the seed turned into a sprout, it is said to have germinated. This is the beginning of life of a new plant.

The germination is possible only when appropriate conditions like moisture air and sunlight is present, hence abiotic factors like air, water, light and heat are important for the growth of plants and all other living organisms.   

A3. How do fishes breathes and why whales and dolphins breathe differently?

Answer:

Fishes breathe through their gills. Gills are specialized organs that are located on either side of the fish's head, behind the eyes.  

There are some sea animals like dolphins and whales that do not have gills. They breathe in air through nostrils or blowholes that are located on the upper parts of their heads. This allows them to breathe in air when they swim near the surface of water. They can stay inside the water for a long time without breathing. They come out to the surface from time to time, to breathe in air.  

A4. What is breathing and respiration, Explain respiration?

Answer:

The inhale and exhale of air is called breathing.  

Breathing is part of a process called respiration.  

In respiration, some of the oxygen of the air we breathe in, is used by the body. We breathe out carbon dioxide produced in this process.  

1. Give two examples each, of modes of transport used on land, water and air.

Examples of land transport:

Answer:

Bus, train, bullock cart, car, bicycle.

Examples of water transport:

Ship, Boat, Ferry, Hovercraft.  

Examples of air transport:

Gliders, Hot air balloons, Airplane, Helicopter.   

2. Fill in the blanks:

(i) One metre is _100_m.  

(ii) Five kilometre is __5000__ m. (iii)Motion of a child on a swing is __Periodic motion (oscillatory motion )__.  

(iv)Motion of the needle of a sewing machine is _Periodic motion (oscillatory motion )__.  

(v) Motion of wheel of a bicycle is__rotational_ motion___.  

3. Why can a pace or a footstep not be used as a standard unit of length?

It can not be used as a standard unit of length because different people have different pace or foot step.

4. Arrange the following lengths in their increasing magnitude: 1 metre, 1 centimetre, 1 kilom,1 mm.

1 millimeter, < 1 centimeter, <1 meter, < 1 kilometer.

5. The height of a person is 1.65 m. Express it into cm and mm.

(a) We know 1 m =100 cm.

1.65m = 1.65 x 100cm

          = 165cm (Answer)

(b)We know 1 cm = 100 mm

First, we will convert. meter into cm, then cm into mm.

Converting into 1.65m in cm.

1.65m = 1.65 x 100cm =165cm

Now, Converting into 165 cm in mm.

165cm= 165x 10mm =1650mm (Answer)

6. The distance between Radha's home and her school is 3250 m. Express this distance into km.

Answer:

We know that 1000 m    =   1 km  

                1m   =   1/1000  km

 3250 m = 3250 x 1/1000 km                                                      

              = 3.25 km (Answer)

7. While measuring the length of a knitting needle, the reading of the scale at one end is 3.0 cm

and at the other end is 33.1 cm. What is the length of the needle?  

Answer:

Length of needle:

= 33.1- 0.3 cm

= 30.1 cm (Answer)

8. Write the similarities and differences between the motion of a bicycle and a ceiling fan that has been switched on.  

Answer

Similarities:

A switched-on fan and cycle paddled on stand(stationary) Both exhibit rotational motion.  

The fan blades are fixed to center rotate on axis.

The rear cycle Tyre is fixed to center and rotate on axis.

Dissimilarities:

Moving fan does not show any displacement (movement from point A to point B) hence only exhibit only rotational motion.

Moving cycle Tyres show displacement hence exhibit both rotational as well as rectilinear motion.  

9. Why would you not like to use a measuring tape made of an elastic material like rubber to measure

Answer:

We would not like to using an elastic measuring tape made of rubber or other stretchable materials because it can stretch and deform under tension. This can lead to inaccurate measurements and errors in the final result.

 The problems we would meet in telling someone about a distance we measured with such a tape is accuracy, because each time the measurement will vary even if measured by the same person multiple times.  

10. Give two examples of periodic motion.

Answer:

Examples of periodic motion are as given below:

(a) oscillations of a pendulum. (Pendulum of a clock comes back to same position)

(b) Motion of swing (child rushes back and forth).

(c) Spring-mass system. (When a mass is attached to a spring and set in motion, the resulting motion is periodic.)

(d) Heartbeat (contraction and relaxation of heart muscles)

(e) Vibrating string (guitar string when plucked)

A1. Define the following (a)yard, (b)cubit, (c)handspan, (d)distance, (e)unit and (f) measurement.

Answer:

(a)Yard: The measure between the end of the outstretched arm and the chin of any person.

(b)Cubit: The measure between the length of the arm from the elbow to the tip of the middle finger.

(c)Handspan: A handspan is the distance from the tip of the little finger in a stretched hand.

Handspan is generally used to measure small objects.

(d)Distance: Distance is defined as the length between any two points.

In earlier days, handspan, cubit and yard where the units to measure distance.

(e)Unit:  A unit is a standardized quantity used to express a physical quantity. Units provide a standard reference point for measuring and comparing physical quantities.  

(f)Measurement:  Measurement is the process of assigning numerical values to physical quantities in order to quantify and compare them. The known quantity is called the unit.

A2. What is SI System? Make conversion chart for length, mass and time.

Answer

"A standard unit means a standard measure that has a definite and convenient quantity, so that it remains the same under all conditions."

For the sake of uniformity, scientists all over the world have accepted a set of Standard units of measurement.  

Various SI units and their conversion are as under.

Length: SI unit - meter (m)  

10 millimeter (mm) = 1 centimeter

10 centimeter (cm) = 1 decimeter

10 decimeter = 1 meter

10 meter = 1 decameter

10 decameter = 1 hectometer

10 hectometer = 1 kilometer  

Mass: SI unit - Kilogram

1000 grams = 1 kilogram

1000 kilograms = 1 ton

Time: SI unit - Second (s)

60 seconds = 1 minutes

60 minutes = 1 hours

24 hours = 1day

 1. Rearrange the boxes given below to make a sentence that helps us understand opaque objects.

OWS AKE OPAQ U E O BJEC T S M SHAD

Answer:

OPAQ U E O BJEC T S M AKE SHAD OWS

(Opaque objects make shadows.)  

2. Classify the objects or materials given below as opaque translucent and luminous or non-luminous:

Answer:

Air: Transparent and non-luminous

• Water: Transparent and non-luminous
• Piece of rock: Opaque and non-luminous
• Sheet of aluminium: Opaque and non-luminous
• Mirror: Opaque and non-luminous
• Wooden board: Opaque and non-luminous
• Sheet of polythene: Translucent and non-luminous
• CD: Translucent and non-luminous
• Smoke: Translucent and non-luminous
• Sheet of plane glass: Transparent and non-luminous
• Fog: Translucent and non-luminous
• Piece of red hot iron: Opaque and luminous
• Umbrella: Opaque and non-luminous
• Lighted fluorescent tube: Opaque and luminous
• Wall: Opaque and non-luminous
• Sheet of carbon paper: Opaque and non-luminous
• Flame of a gas burner: Opaque and luminous
• Sheet of cardboard: Opaque and non-luminous
• Lighted torch: Opaque and luminous
• Sheet of cellophane: Translucent and non-luminous
• Wire mesh: Opaque and non-luminous
• Kerosene stove: Opaque and luminous
• Sun: Opaque and luminous
• Firefly: Translucent and luminous
• Moon: Opaque and non-luminous.

3. Can you think of creating a shape that would give a circular shadow if held in one way and a rectangular shadow if held in another way?

Answer:

Yes, a cylindrical shape because the shape of the shadow depends on the shape of the cross-section of the object that is being illuminated. When the circular base of the cylinder is facing the light source, the cross-section is also circular, and so the shadow cast will be circular. But when the rectangular cross-section is facing the light source, the shadow cast will be rectangular, because that is the shape of the cross-section that is being illuminated.  

4. In a completely dark room, if you hold up a mirror in front of you, will you see a reflection of yourself in the mirror?

Answer:

No, if you are in a completely dark room, and you hold up a mirror in front of you, you will not see a reflection of yourself in the mirror. Because In order to see a reflection in a mirror, light needs to be present.  

A1. What do you mean by Luminous, Non luminous, objects, opaque transparent and translucent objects?

Answer:

Luminous objects are those that emit their own light, such as a light bulb, the sun, or a firefly.  

Non-luminous objects do not emit their own light, but can be seen because they reflect light from a luminous object, such as the moon or a book on a table.

Opaque objects are those that do not allow light to pass through them. When light falls on an opaque object, it is either reflected or absorbed, but does not pass through. Examples of opaque objects include a piece of wood or a rock.

Transparent objects are those that allow all light to pass through them. When light falls on a transparent object, it passes through without being scattered. Examples of transparent objects include a sheet of glass or a clear plastic bottle.

Translucent objects are those that allow some light to pass through them, but not all. When light falls on a translucent object, it scatters in different directions as it passes through, making objects behind the translucent object appear blurred.  Examples of translucent objects include a frosted glass window or a sheet of wax paper.

A2. What is shadow and how is it formed?

Answer:

A shadow is a dark area or shape produced by an object coming between a source of light and a surface.

Shadows are formed when light is blocked by an opaque object, causing a region of darkness to appear on a surface behind the object. The size and shape of the shadow depend on the position, size, and shape of the object, as well as the angle and intensity of the light source.  

The formation of a shadow involves three components: a source of light, an opaque object, and a surface for the shadow to fall upon. When light from the source falls on the opaque object, it is blocked and a shadow is formed on the surface behind it.

The size and shape of the shadow depend on the distance between the object and the surface, the size of the object, and the angle of the light source. When the light source is closer to the object, the shadow appears larger and fuzzier, while a farther light source will produce a smaller and sharper shadow.   

A3. What is a pin hole camera how does it work?

Answer:

A pinhole camera, also known as a camera obscura, is a simple optical device that uses a tiny aperture to create an image of the outside world on a surface inside the camera.  

The basic principle of a pinhole camera is to allow light to pass through a small hole or aperture, and then project an inverted image of the outside world onto a surface like transparent paper inside the camera.   

A4. how do we know that light travels in a straight line give explanation?

Answer:

We can look at a light source through an empty tube, but we cannot see it if the tube is bend. Shows the light travels in straight line.

Explanation:

When we look at a light source through an empty straight tube, the light enters the tube and travels in a straight line until it reaches our eyes, allowing us to see the light source at the other end of the tube.      However, if the tube is bent, the light cannot travel in a straight line through the tube and instead follows the path of the curve. As a result, the light does not reach our eyes and we cannot see the light source.   

A5. What is mirror and reflection?

Answer:

Mirror:  A mirror is a smooth and polished surface that reflects light in a way that forms an image of whatever is in front of it.  

Mirrors are commonly made of glass with a metallic backing, such as aluminum or silver, that reflects the light that strikes it.

Reflection: The process of bouncing back of the light rays when they fall on on any shiny surface.  

This reflection of light is what allows us to see our own reflection in a mirror. The light that enters our eyes after reflecting off the mirror creates an image of ourselves that appears to be behind the mirror, as though we are looking through a window.  

1. Fill in the blanks:

(a) A device that is used to break an electric circuit is called __switch__.  

(b) An electric cell has _two_ terminals.

2. Mark 'True' or 'False' for following statements:

(a) Electric current can flow through metals..... (True )  

(b) Instead of metal wires, a jute string can be used to make a circuit..... (False )

(c) Electric current can pass through a sheet of thermocol...... (False )  

3. Explain why the bulb would not glow in the arrangement shown in Figure 12.13. 

Answer:

The bulb will not glow in the arrangement shown in the figure because one end of screwdriver is made up of plastic and we know that plastic is bad conductor or electricity means the will not allow electric current to pass through it.

Hence the bulb would not glow.  

4. Complete the drawing shown in Figure 12.14 to indicate where the free ends of the two wires should be joined to make the bulb glow.  

Answer:

One terminal of the switch needs to be connected to the vacant terminal of the bulb and other terminal of the switch needs to be connected to the vacant terminal of the electric cell.

This will complete the circuit.

5. What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.

Answer:

The purpose of using an electric switch is to control the flow of electricity in a circuit. An electric switch can be used to turn on or off the power to an electrical device.   

Lights: Light bulbs have switches built into them, allowing us to turn them on or off as needed.

Fans: Ceiling fans, table fans, and other types of fans have switches that control the speed and direction of the blades.

Televisions: Television sets have switches that turn them on and off.

Computers: Computers have switches that turn them on and off.

Refrigerators: Refrigerators have switches that turn them on and off.

Air conditioners: Air conditioners have switches that turn them on and off.

Mobile: Mobile phone has power on and power off switch etc.

6. Would the bulb glow after completing the circuit shown in Figure if instead of safety pin we use an eraser.

Answer:

No, the bulb will not glow after completing the circuit shown in figure, if instead of safety pin we use an eraser, because eraser is made up of rubber and as we know rubber is an insulator so it will not conduct electricity.

7. Would the bulb glow in the circuit shown in Figure?

Answer:

No, the bulb will not glow, as both the wires from the cell are connected to the same terminal of the bulb.

whereas it should be connected to the different terminals.

8. Using the "conduction tester" on an object it was found that the bulb begins to glow. Is that object is a conductor or an insulator? Explain.

Answer:

The object a conductor.

This is because the conduction tester is designed to detect the presence of electrical current, and a glowing bulb indicates that there is a flow of electricity through the object.     

9. Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.

Answer:

The electrician should use rubber gloves while repairing an electric switch at our home, because rubber is an insulator rubber gloves provide a layer of insulation between the electrician's skin and the electrical current.

Hence for safety reasons electrician should use rubber gloves and save himself from shock.  

10. The handles of the tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber covers on them. Can you explain why?  

Answer:

Yes, the handles of tools used by electricians often have plastic or rubber covers on them for safety reasons. These covers serve as insulators, preventing the electrician from coming into direct contact with any live electrical components or circuits.

Additionally, the plastic or rubber covering can provide a better grip on the tool, which can improve control and reduce the risk of dropping the tool.   

A1. What is an electric cell, electric circuit and electric bulb?  

Answer:

Electric cell:

Electric cell is a source of electricity. An electric cell has two terminals; one is called positive (+ ve) while the other is negative (– ve).

Electric circuit:

An electric circuit is a pathway through which electric current flows.

When electric current flows from the power source through the circuit and returns to the power source, completing the loop.  

It is termed as closed loop or closed circuit. This enables a switch on position.

 When electric current flows from the power source through the circuit and does not return to the power source, completing the loop.

It is termed as open loop or open circuit. This enables a switch off position.

Electric bulb:

An electric bulb has a filament that is connected to its terminals. An electric bulb glows when electric current passes through it.

1. Fill in the blanks in the following

Answer:

(i) Artificial magnets are made in different shapes such as _____bars, horseshoes, Needle magnet, cylindrical, oval shaped magnet, and spherical or ring magnet__.  

(ii) The Materials which are attracted towards a magnet are called___magnetic material__.  

(iii) Paper is not a ____magnetic_ material__.  

(iv) In olden days, sailors used to find direction by suspending a piece of ___bar magnet___.  

(v) A magnet always has ____a pair of_ poles___.  

2. State whether the following statements are true or false:

Answer:

(i) A cylindrical magnet has only one pole (False )  

(ii) Artificial magnets were discovered in Greece (True )

(iii) Similar poles of a magnet repel each other (True )

(iv) Maximum iron filings stick in the middle of a bar magnet when it is brought near them (False )

(v) Bar magnets always point towards North-South direction (True )

(vi) A compass can be used to find East-West direction at any place (False )  

(vii) Rubber is a magnetic material (False )

3. It was observed that a pencil sharpener gets attracted by both the poles of a magnet although its body is made of plastic. Name a material that might have been used to make some part of it.

Answer:

The pencil sharpener might have a blade made of steel or iron, which is a magnetic material.   

4. Column I shows different positions in which one pole of a magnet is placed near that of the other. Column II indicates the resulting action between them for each situation. Fill in the blanks.

Answer:

Column I Column II

N - N-------------Attraction

N - S-------------Attraction

S - N-------------Attraction

S – S--------------Repulsion

5. Write any two properties of a magnet.

Answer:

A magnet has two poles north pole and south pole, irrespective of its size and shape.

Like poles of magnet repel each other and opposite pole of magnet attracts.

6. Where are poles of a bar magnet located?

Answer:

The poles of a bar magnet are located at its two ends.  

One end is called the north pole and the other end is called the south pole.  

7. A bar magnet has no markings to indicate its poles. How would you find out near which end is its north pole located.

Answer:

We can suspend the bar magnet freely using a string to allow it to stop on its own. The magnet will align itself with the Earth's magnetic field, with its north pole pointing towards the geographic North Pole and its south pole pointing towards the geographic South Pole.  

By observing which end of the magnet points towards the North Pole, you can determine which end is its north pole.  

8. You are given an iron strip. How will you make it into a magnet?

Answer:

This can be done by the process of magnetization. Here are the steps to follow:  

Without lifting rub one of the poles of a permanent magnet along the length of the clean iron strip.

Repeat this process 30 to 40 times, remember to continue in one direction only.  

This process is known as stroking the iron strip.

Bring some iron filling near the strip and observe that the strip attracts the filing.

Hence, the iron strip is magnetized.

9. How is a compass used to find directions?

Answer:

A compass is a navigational tool that is used to find directions, specifically north, south, east, and west.  

It works by aligning its needle with the Earth's magnetic field. The north pole of the magnetic needle aligns with geographic north, and this helps determine the other directions.  

10. A magnet was brought from different directions towards a toy boat that has been floating  in water in a tub. Affect observed in each case is stated in Column I. Possible reasons for the observed affects are mentioned in Column II. Match the statements given in Column I with those in Column II.  

Answer:

Column A .......... Column B     

      (a)......................(4)

      (b)......................(5)

      (c)......................(1)

      (d)......................(3)

      (e)......................(2)

A1. Do magnet lose their properties? How can this be avoided?

Answer:  

Yes, Magnets lose their properties if they are heated, hammered or dropped from some height. Also, magnets become weak if they are not stored properly.

To avoid and keep them safe:  

Bar magnets should be kept in pairs with their unlike poles on the 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.  

Keep magnets away from cassettes, mobiles, television, music system, compact disks (CDs) and the computer.

A2. Answer the following:

Answer:

(a) Who discovered magnet?

It is said that there was a shepherd named 'Magnes' who accidentally discovered magnet.

Magnet exit naturally as some people believe that magnetite was first discovered at a place called Magnesia, hence gets. its name.   

(b) Name the rock from which magnet was discovered.?

Magnet exit naturally as a rock named magnetite, as some people believe that magnetite was first discovered at a place called Magnesia, hence gets. its name.

(c) What is a magnetic material?

The materials which get attracted towards a magnet are magnetic – for example, iron, nickel or cobalt.  

(d) What are non-magnetic material?

The materials which are not attracted towards a magnet are non-magnetic  

material. for example, soil, pencil or wood.  

(e) Do you observe that more iron filings get attracted to some parts of the magnet?

Yes, more iron filling gets attracted towards the North pole of the magnet.  

1. Fill up the blanks in the following:

Answer:

(a) The process of changing of water into its vapour is called __evaporation_or__vaporization_.  

(b) The process of changing water vapour into water is called ___condensation______. 

(c) No rainfall for a year or more may lead to ___drought__ in that region.  

(d) Excessive rains may cause __floods___.  

2. State for each of the following whether it is due to evaporation or condensation:

Answer:

(a) Water drops appear on the outer surface of a glass containing cold water........... condensation 

(b) Steam rising from wet clothes while they are ironed.......... evaporation

(c) Fog appearing on a cold winter morning...........condensation.

(d) Blackboard dries up after wiping it.................evaporation 

(e) Steam rising from a hot girdle when water is sprinkled on it....... evaporation

3. Which of the following statements are “true”?

Answer:

(a) Water vapour is present in air only during the monsoon...... (False )  

(b) Water evaporates into air from oceans, rivers and lakes but not from the soil....... (False ) 

(c) The process of water changing into its vapour, is called evaporation....... (True )  

(d) The evaporation of water takes place only in sunlight....... (False )  

(e) Water vapour condenses to form tiny droplets of water in the upper layers of air where it is cooler.(True )  

4. Suppose you want to dry your school uniform quickly. Would spreading it near an anghiti or heater help? If yes, how?

Answer:

Yes, spreading your school uniform near an anghiti or heater can help to dry it quickly.

The heat from the anghiti or heater will help to evaporate the moisture in the fabric of the uniform and make it dry.

5. Take out a cooled bottle of water from refrigerator and keep it on a table. After some time you. notice a droplets of water around it. Why?

The droplets are formed due to the process called condensation. because of temperature difference between the cold bottle and the warmer surrounding, air around the bottle looses heat and changes into water molecules.

Therefore, the droplets of water around the bottle are simply water vapor in the air that has cooled down and condensed into liquid form due to the temperature difference between the bottle and the surrounding air.  

6. To clean their spectacles, people often breathe out on glasses to make them wet. Explain why the glasses become wet. 

Answer:

When people breathe out onto their spectacles, they release warm, moist air from their lungs onto the cool surface of the glasses.  

The moisture in the air then condenses on the glasses, causing them to become wet.  

7. How are clouds formed?

Answer:

The process by which cloud formation takes place is called "condensation." 

Clouds are formed when warm, moist air rises and cools, causing the water vapor in the air to condense into tiny water droplets or ice crystals.  

These droplets or crystals then come together to form visible clouds in the atmosphere. 

8. When does a drought occur?

Answer:

A drought occurs when there is a  below-average rainfall for some years or when the amount of available water falls below the normal range for a particular region, resulting in water shortages and dry conditions.  

 Q1. How does it rain? What is meant by rain water harvesting? 

Answer:

The process by which rain happens is called "precipitation." 

     Precipitation occurs when water droplets in clouds become large enough to fall to the ground due to the force of gravity.  The water vapor in the air condenses to form tiny droplets of water, which appear as clouds. Many tiny water droplets come together and fall down as rain, snow or hail. One way of increasing the availability of water is to collect rainwater and store it for later use.        Collecting rainwater in this way is called rainwater harvesting.  The basic idea behind rainwater harvesting is “Catch water where it falls”. There are two techniques of rainwater harvesting:1. Rooftop rainwater harvesting: In this system the rainwater is collected from  the rooftop to a storage tank, through pipes. This water may contain soil from the roof and need filtering before it is used. 

2. Permeable pavements: Another option is to allow water to go into the ground directly from the roadside drains that collect rainwater this water can recharge groundwater supplies.
 

Q2. What are various uses of water ?

Answer :

Water is essential for life, and it has numerous uses, some of which include:

1. Drinking and hydration for humans and animals.
2. Agricultural uses such as irrigation, livestock, and aquaculture.
3. Industrial uses such as cooling, manufacturing, and energy production.
4. Domestic uses such as cleaning, washing, and sanitation.
5. Recreational uses such as swimming, fishing, and boating.
6. Environmental uses such as maintaining aquatic ecosystems and wildlife habitats.
7. Transportation and navigation.
8. Firefighting and emergency response.
9. Tourism, hydrotherapy, and other leisure activities.

Q3. what is water cycle? Is it useful, Explain your answer. 

Answer:

The circulation of water between ocean and land is known as the water cycle  This circulation of water between ocean and land is a continuous process. This maintains the supply of water on land. The cycle begins with the evaporation of water from the Earth's surface, such as from lakes, rivers, and oceans, as well as from plants and trees through a process called transpiration.  The water vapor then rises into the atmosphere, where it cools and collects to form clouds This process is called condensation. These clouds when become heavy and large enough fall to the ground due to the force of gravity in the form of rain, snow, sleet, or hail. This process is called   precipitation, which falls back to the surface of the Earth.  Some of the rain water is absorbed by the soil and vegetation, while the rest runs off into rivers and streams, eventually making its way back to the oceans. Uses of water cycle or Importance: 

• The water cycle plays a vital role in maintaining the Earth's water balance and provides water for plants, animals, and human use. 
• It also helps to regulate the Earth's temperature and climate by redistributing heat from the equator to the poles. 

Q4. what is ground water, Explain your answer. 

Answer:

The rainwater fills up the lakes and ponds. A part of the rainwater gets absorbed by the ground and seems to disappear in the soil.   Some of the water is used by plants and animals. The rest seeps into the ground. Most of this water becomes available to us as ground water or the water that gets stored in the hollow spaces deep in the ground acts as a big reservoir of water. The level of this ground water is called water table. Uses of ground water:

• Open wells are fed by ground water. 
• Ground water is the source for many lakes as well. 
• It is also this ground water which is drawn by a handpump or a tubewell. 

1. What is the composition of air?

Answer:

Air is composed of a mixture of gases,  

• nitrogen (78%)  
• oxygen (21%),
• carbon dioxide (0.04%)
• argon and other gases (0.93%),
• neon, helium, methane, krypton, hydrogen, and xenon (all less than 1% combined).

Additionally, air also contains varying amounts of water vapor, depending on the humidity of the surrounding environment.  

2. Which gas in the atmosphere is essential for respiration?

Answer:  

The gas in the atmosphere that is essential for respiration is oxygen (O2). Oxygen is required for the process of cellular respiration, which is how cells generate energy.  

3. How will you prove that air supports burning?

Answer:

This can be proved with the help of an experiment:

• Fix two small candles of the same length on a  table.  
• Light both the candles.  
• Cover one of the candles with an inverted glass tumbler.
• The candle covered with glass tumbler extinguishes after some time, whereas the other candle continued burning. This shows that air supports burning.

4. How will you show that air is dissolved in water?

Answer:

Take some water in a glass or metal container.  

Heat it slowly on a tripod stand.  

Well before the water begins to boil, we can see tiny bubbles on the inner surface of the container.

These bubbles come from the air dissolved in water.  

When we heat the water, the air dissolved in it escapes in the form of bubbles.  

5. Why does a lump of cotton wool shrink in water?

Answer:

The lumps of cotton bolls have air gaps which are filled with air.

When cotton ball is immersed in water the air trapped in between fibers gets replaced with water molecules.

This removes the gap in-between fibers and makes them shrink.  

6. The layer of air around the earth is known as ___________.

Answer:

The layer of air around the earth is known as __atmosphere__.  

7. The component of air used by green plants to make their food, is ___________.

Answer:

The component of air used by green plants to make their food, is ___carbon_ _dioxide ( CO₂)___.  

8. List five activities that are possible due to the presence of air.

Answer:

The uses of air or the presence of air makes several activities possible. Here are five activities that are made possible due to the presence of air:

1. Breathing: Humans and other animals are able to breathe in oxygen-rich air, which is necessary for cellular respiration and survival.
2. Flying: Airplanes and other aircraft use the air's density and resistance to create lift, allowing them to fly through the air.
3. Sailing: Sailing boats use the force of the wind to move across bodies of water, thanks to the presence of air currents.
4. Drying: The movement of air helps to evaporate water from wet surfaces, allowing clothes and other items to dry more quickly.
5. Photosynthesis: Plants take carbon dioxide gas from the air to make their food.
6. Fun: Moving air is used to move Fikri by children.

9. How do plants and animals help each other in the exchange of gases in the atmosphere?

Answer:

 Plants and animals help each other in the exchange of gases in the atmosphere through the process of photosynthesis and respiration.  

During day, plants absorb carbon dioxide (CO2) from the atmosphere and use energy from the sun to convert it into oxygen (O2) and glucose (sugar). The oxygen produced during photosynthesis is then released into the atmosphere as a byproduct, which can be used by animals for respiration.

During respiration, animals absorb oxygen from the atmosphere and use it to break down glucose and other organic molecules to produce energy. This process releases carbon dioxide as a waste product, which can be absorbed by plants for photosynthesis.   

Q1. There are two colorless and order less gases in jars A and B. One is oxygen and other is carbon dioxide. How will do you detect which jar contain oxygen and which jar contain carbon dioxide?

Answer:

We will put candles in both jars and now we will try to burn the candles. The jar in which candle will burn contains oxygen gas and in which candle will not burn contains carbon dioxide gas.

Q2. Take an empty open bottle. Is it really empty or does it have something inside? Turn it,

upside down. Is something inside it, now? Explain your answer?

Answer:

Yes, there is air inside this bottle because air is present everywhere.

We can explain this buy dipping the open mouth of the bottle into the bucket filled with water. when we tilt the bottle slightly, we can see bubbles coming out of the mouth of bottle and can also hear the bubbly sound.  

The bottle was not empty at all.  

This experiment also shows that air occupies space.  

Q3. Why do you think mountaineer carry oxygen cylinders with them, while climbing high mountains?

Answer:

The mountaineers do so while climbing high mountains, because there is lack of oxygen on high altitudes.

Picture questions form the book:

Observe the picture on the book carefully and answer the following questions.

(a) What is covering the nose and the mouth of the policeman?

Answer:

 The policeman has covered his mouth and nose with a mask with charcoal lining because charcoal has activated carbon which absorbs most of the air pollutants, dust pollen etc.  

(b) Why is he putting a cover on his nose?

Answer:

He is doing so because there is so much pollution on the road created by exhaust of vehicles and also air carries dust particles.

(c) can you comment on the air quality of the place shown in the figure?

Answer:

The air quality of this place is very bad, there is so much pollution on the place that the police is also wearing mask.

There are vehicles that are emitting poisonous gases like carbon monoxide. Also, there are lots of sounds, hence noise pollution is also present.

(d) Why earthworm come out of the soil during rainy season.

Answer:

Animals live in burrows and holes which are formed in the deep soil, burrows also make spaces available for air to move on and out of soil. Moreover, when it rains heavily water. fills up all the spaces occupied by the air in the soil and to avoid dowsing.

In this situation animals living in the soil have to come out for respiration.

(e) Write the use of windmill?

Answer:

The uses of windmill are-

To draw the water from tube well.

To run flour mill.

To generate electricity.

(f) What are the properties of air?

Answer:

Some properties of air are as under:

• Air is tasteless.
• Air is colorless.
• Air has mass.
• Air occupies space.
• Air can be compressed.
• Air dissolves in water.

1. (a) Which kind of garbage is not converted into compost by the red worms?

Answer:

 The shiny or plastic-coated paper should is not converted into compost by the redworms.

(b) Have you seen any other organism besides red worms, in your pit? If yes, try to find out their names. Draw pictures of these.  

Answer:

Yes, other insects are maggots, flies, ants and cockroaches,

2. Discuss :

(a) Is garbage disposal the responsibility only of the government?

Answer:

Yes, garbage disposal the responsibility government however citizens can also contribute by reducing the waste content and avoiding littering.  

We should use separate bins for dry and wet garbage.

Some wastes are hazardous and need to be delt professionally only govt can handle it and dispose correctly.

(b) Is it possible to reduce the problems relating to disposal of garbage?

Answer:

yes, it is possible to reduce the problems relating to disposal of garbage if following measures are taken.

Garbage should not be littered and should be disposed in proper bin.

For wet garbage green bin and for dry garbage blue bin should be used.

We should try to reuse things in some other work eg and empty bottle can be used to store other things.

We should stop using use and throw things.

Reduce the use of non-bio-degradable waste like plastic.

3. (a) What do you do with the left over food at home?

Answer:

We make another dish out of it like we make kheer with left over rice.

And sometimes we also feed stray animals.  

(b) If you and your friends are given the choice of eating in a plastic plate or a banana leaf platter at a party, which one would you prefer and why?

Answer:

1. I will prefer banana leaf, because this will not harm environment.
    
2. Food will taste good in it.
    
3. It is nontoxic, so is safe for my health unlike plastic which is a chemical compound

 4. Collect pieces of different kinds of paper. Find out which of these can be recycled.

Different pieces of paper that we can get are from notebook, textbook, newspaper, magazine. Callander etc.

Answer:

All of the paper can be recycled with a little chemical treatment to make it white gain, as we know paper is made of cellulose that comes from bamboo and work etc.

(b) With the help of a lens look at the pieces of paper you collected for the above question. Do you see any difference in the material of recycled paper and a new sheet of paper?

Answer:

 We do not see any major difference in the material of recycled paper and a new sheet of paper, but the new paper is more shiny and strong.   

5. (a)Collect different kinds of packaging material.

(b) What was the purpose for which each one was used? Discuss in groups.

Answer:

Different kinds of packaging material collected are:  

• Thermacol: Used to pack Computer, Laptop and gift articles.
   
• Polythene sheets: Used to pack washing machine, refrigerator and lawn mover.
   
• Polythene bag: Used to pack dal, sugar, tea leaves and biscuit.
   
• Cardboard: Used to pack mobile phone, Lcd etc.
   
• Wood: Wood Pannels and strips are used to pack and transport, window glass safely.  
   

(b) Give an example in which packaging could have been reduced?

Answer:

Packing could have been reduced in Mobile phone and lawn mower.

(c) Write a story on how packaging increases the amount of garbage.

Answer:

Amandeep loved shopping, but she never thought about the impact of her purchases on the environment.  

One day, she decided to clean her room, and as she looked at the pile of trash bags, she realized something.  

Most of the waste was packaging - cardboard boxes of pizza, plastic wraps, and empty biscuit wafers, chocolate wafers and tin of soda cans.

She felt guilty and decided to change her habits she realized how packaging increase the amount of garbage.

She started buying items with minimal packaging, opting for bulk purchases and using reusable bags.  

Her actions reduced her garbage output, and she felt good about her decision.  

she spread the word to her friends and family that and was praised by everybody.  

6. Do you think it is better to use compost instead of chemical fertilizers? Why?

Answer:

Yes, I believe it is better to use compost instead of chemical fertilizers for several reasons.

• Compost is a natural fertilizer made from organic waste, Chemical fertilizers, on the other hand, are made from synthetic materials and can harm the environment.
   
• Compost improves soil health by adding beneficial microorganisms that help break down organic matter and release nutrients to plants. Chemical fertilizers, on the other hand, can cause a build-up of salts in the soil, which can harm plants in the long run.
   
• Compost use helps to reduce waste by diverting organic matter from landfills.
   
• Hence, compost is a more sustainable and environmentally friendly option compared to chemical fertilizers. It helps to improve soil health, reduce waste, and promote sustainable gardening practices.  

Q1. What can you do to minimize overuse of plastics and deal with garbage?

Answer:

To minimize overuse of plastics and deal with garbage following can be done:

1. We can make a minimum use of plastic bags. We re-use the bags whenever it is possible.

2. We can minimise over use of plastics and deal with garbage insist shopkeepers use paper bags. We can carry a cloth or a jute bag when we go out for shopping.  

3. We may not use plastic bags to store eatables.  

4. We do not throw plastic bags here and there, after use.  

5. We can avoid burning plastic bags and other plastic items.  

6. We can stop putting garbage in plastic bags and throw it away.  

7. We can use vermicomposting at home and deal with our kitchen waste usefully.  

8. We can recycle paper.  

9. We can use both sides of the paper to write. We can use a slate for rough work. We use blank sheets of paper left in our notebooks for rough work.  

10.We can make our family, friends and others to follow proper practices for disposing different kinds of wastes.

Q2. Why we should not throw polythene bags in landfills or garbage bins?

Answer:

Plastics give out harmful gases, upon heating or burning. These gases may cause many health problems, including cancer,  

• When stray animals look for food in these bags, they end up swallowing these. Sometimes, they die due to this.  
   
• The plastic bags thrown away carelessly on roads and other places get into drains and the sewer system as a result, drains get choked and the water spills on the roads.  
   

Q3. Define Vermicompost and land Landfill.

Answer:

This method of preparing compost with the help of redworms is called vermicomposting.

It is excellent natural fertilizer pots, gardens or fields. It is like getting the ‘best out of waste.'  

Landfill is an area where the garbage collected from a city or town is dumped. The area is later converted into a park.  

Q4. What is the difference between Vermicompost and Compost

Answer:

Compost is made from a variety of organic materials, such as food scraps, yard waste, and leaves. These materials are piled together and allowed to decompose over time, with the help of beneficial microorganisms that break down the material. The resulting product is a nutrient-rich soil amendment that can be used to improve soil health and plant growth.

Vermicompost, on the other hand, is made by adding organic matter to a vermicomposting system, which uses worms to break down the material. The worms consume the organic matter and digest it, producing a nutrient-rich compost that is high in beneficial microorganisms and plant growth hormones.  

Vermicompost is particularly rich in nitrogen, phosphorus, and potassium, making it an excellent fertilizer for plants.