CBSE Class 6 Science All Chapters Worksheet Set 04

Assignment - I, II, III (Motion and Measurement of Distances)

Question Q.1. Name the following:
(i) Any ancient means of transport
(ii) S.I unit for measuring length
(iii) Motion in a straight line
(iv) S.I. unit of time is
(v) Full form of S.I. unit is
(vi) Motion that repeats itself at regular intervals of time is called
Answer: (i) Boat or Animal transport (like horse, camel)
(ii) Metre
(iii) Rectilinear motion
(iv) Second
(v) International System of Units
(vi) Periodic motion
In simple words: These are standard scientific terms and historical facts related to measurement and transport.

Exam Tip: Always remember that the standard International System of Units is abbreviated as SI units, and metre is the fundamental unit of length.

Question Q.2. State True or False-
(i) One metre is equal to 1000 centimetre.
(ii) Motion of a wheel is circular motion.
(iii) Metre scale is used to measure length and breadth.
(iv) ‘Foot’ is a unit of length.
(v) A curved line can be measured with the help of a scale only.
(vi) Both oscillatory and vibratory motions are examples of periodic motions.
(vii) A metre rod can be used to determine mass of a body.
(viii) For correct measurement of length, we should see the metre scale from one side.
Answer: (i) False (1 m = 100 cm)
(ii) False (Motion of a wheel is rotatory/circular, but more precisely it possesses both translatory and rotatory motion, though often treated as rotatory/circular depending on context; strictly speaking, wheel about a fixed axle is rotatory)
(iii) True
(iv) True (non-standard unit)
(v) False (A curved line is measured using a thread or divider, not a scale directly)
(vi) True
(vii) False (A metre rod measures length, not mass)
(viii) False (Eye must be exactly in front of the point where the measurement is to be taken to avoid parallax error)
In simple words: Correct measurement techniques and unit conversions are tested here.

Exam Tip: Watch out for false statements involving parallax error and direct measurement of curved paths.

Question Q.3. Fill in the blanks
(i) The wheel of a moving bicycle describes ___________ and __________ motion.
(ii) Kelvin is the unit of ___________.
(iii) The early people used to domesticate ____________ to help them move form one place to another.
(iv) The invention of the ___________ proved to be a revolution in our means of transportation.
(v) Lengths more than 1m are measured by ___________.
(vi) Every measurement consists of a ___________ and a __________.
(vii) Movement of pencil on paper while writing is an example of _______ motion.
(viii) 1m = ……………………cm
(ix) 1km = ……………………mm
(x) 5m = ……………………dm
(xi) 1000m = ……………………km
(xii) 15cm = ……………………mm
Answer: (i) Translatory, rotatory
(ii) Temperature
(iii) Animals (like horses/donkeys)
(iv) Wheel
(v) Metre rod or measuring tape
(vi) Number, unit
(vii) Rectilinear / Translatory
(viii) 100
(ix) 1000000 (1 km = 1000 m = 1000000 mm)
(x) 50 (1 m = 10 dm, so 5 m = 50 dm)
(xi) 1
(xii) 150
In simple words: Fill in the blanks test units of length conversion and types of motion.

Exam Tip: Practice metric conversions carefully: \(1\text{ km} = 1000\text{ m} = 100,000\text{ cm} = 1,000,000\text{ mm}\).

Question Q.4. Match the following-
(i) Temperature (a) Kilogram
(ii) Mass (b) Degree celsius
(iii) Length (c) Square metre
(iv) Time (d) Metre
(v) Area (e) Degree
(f) Second
Answer: (i) -> (b) Degree celsius
(ii) -> (a) Kilogram
(iii) -> (d) Metre
(iv) -> (f) Second
(v) -> (c) Square metre
In simple words: Matching physical quantities with their standard units.

Exam Tip: Learn physical quantities and their SI units thoroughly.

Question Q.5. Choose the correct answer-
(i) One day is equal to-
(a) 1600 minutes
(b) 85000 seconds
(c) 86400 seconds
(d) None of these
Answer: (c) 86400 seconds
1 day = 24 hours
1 hour = 60 minutes = 3600 seconds
Total seconds = \(24 \times 3600 = 86400\text{ seconds}\)
In simple words: Multiply hours, minutes, and seconds to find total seconds in a day.

Exam Tip: Memorize conversion factors for time: 1 hour = 3600 s.

Question (ii). A drill used by a carpenter executes
(a) Only translatory motion
(b) Only a rotatory motion
(c) Both translatory motion and rotatory motion
(d) Only circular motion
Answer: (c) Both translatory motion and rotatory motion
A carpenter's drill rotates around its axis (rotatory) and moves forward into the wood (translatory).
In simple words: The drill spins while moving inside the wood.

Exam Tip: Tools like drills and screws combine rotational and translational motions.

Question (iii). The motion executed by a swing is-
(a) An oscillatory motion
(b) A translatory motion as well as rotatory motion
(c) A rotatory motion
(d) A Translatory motion as well as oscillatory motion
Answer: (a) An oscillatory motion
A swing moves to and fro about its mean position, which defines oscillatory motion.
In simple words: A swing moves back and forth repeatedly.

Exam Tip: To-and-fro motion is always classified as oscillatory or vibratory.

Question (iv). The handle and needle of a sewing machine
(a) Both execute a rotatory motion
(b) Both execute a translatory and an oscillatory motion
(c) Execute different types of motions
(d) Both execute a circular motion.
Answer: (c) Execute different types of motions
The wheel/handle executes rotatory motion while the needle executes to-and-fro (oscillatory/periodic) motion.
In simple words: Different parts of a machine perform different types of motions.

Exam Tip: Complex machines consist of parts performing distinct types of motion.

Assignment - IV, V, VI (Fun with Magnets)

Question Q.1. Classify the following as Magnetic and Non-Magnetic materials:
a) A Compass
b) Iron rod
c) Cobalt
d) Plastic
e) Register
Answer: Magnetic materials: Iron rod, Cobalt, A Compass (contains a magnetic needle).
Non-Magnetic materials: Plastic, Register.
In simple words: Materials attracted by a magnet are magnetic, others are non-magnetic.

Exam Tip: Iron, cobalt, and nickel are magnetic metals.

Question Q.2. What is a Magnes Stick?
Answer: A Magnes stick is a wooden stick with a small piece of lodestone (natural magnet) attached at one end, traditionally used by shepherds in ancient Greece (Magnesia) to control their cattle and find iron nails in shoes.
In simple words: An ancient walking stick tipped with a magnet.

Exam Tip: Connect the origin of the word 'magnet' to Magnesia and Magnes sticks.

Question Q.3. Study the following diagram:
a) Why did the iron fillings stick to the magnet?
b) As shown in the diagram, most iron fillings stick towards the ends of the magnet. Why?
c) What will you observe if another magnet is brought near the ends of the magnet?
Answer: (a) Iron filings are magnetic substances, hence they get attracted to the magnet.
(b) The magnetic force of a bar magnet is strongest at its poles (ends).
(c) Attraction or repulsion will be observed depending on whether unlike or like poles are brought close to each other.
In simple words: Magnets attract iron most strongly at their poles.

Exam Tip: Poles always hold the maximum magnetic strength.

Question Q.4. State true or false for the following-
(i) The ‘N’ poles of two magnets attract each other.
(ii) Repulsion is the only sure test of magnetism.
(iii) Magnetism is strongest at the centre of a bar magnet.
(iv) Wood is attracted to magnet.
(v) Substances which get attracted to a magnet are called conductors.
Answer: (i) False (Like poles repel)
(ii) True
(iii) False (It is strongest at the poles/ends)
(iv) False
(v) False (They are called magnetic substances)
In simple words: Like poles repel, and magnetic attraction applies to magnetic materials, not conductors of electricity.

Exam Tip: Remember: Repulsion is the sure test because a magnet can attract an unmagnetized iron piece, but it only repels another magnet.

Question Q.5. Match the following-
(i) Lodestone (a) protect magnets not in use
(ii) Electromagnets (b) natural magnets
(iii) Single touch method (c) compass needle
(iv) Sailors and navigators (d) to magnetise a bar
(v) Hammering (e) demagnetize magnet
(vi) Keepers (f) electric bell
Answer: (i) -> (b) natural magnets
(ii) -> (f) electric bell
(iii) -> (d) to magnetise a bar
(iv) -> (c) compass needle
(v) -> (e) demagnetize magnet
(vi) -> (a) protect magnets not in use
In simple words: Matching magnetic terms with their correct definitions or applications.

Exam Tip: Keepers preserve magnets from losing their magnetic properties.

Question Q.6. Choose the correct answer-
(i) The attractive power of a rectangular bar magnet is maximum.
(a) Only at its left end
Answer: (b) At both its ends (poles) *(Note: Completed based on standard options)*
In simple words: Poles at both ends have maximum strength.

Exam Tip: Magnetic strength is concentrated at the two poles.

Question Q.1. Tick the correct option:
a) Water is essential because it is used
1) to generate electricity 2) to run steam engines
3) to sustain life 4) all of the above
b) The main sources of water are…..
1) Ponds 2) Rainfall or snowfall
3) Rivers 4) All of the above
Answer: a) 4) all of the above
Answer: b) 2) Rainfall or snowfall
In simple words: Water has multiple vital uses and originates primarily from rain and snow.

Exam Tip: Precipitation (rain/snow) is the ultimate source of all fresh water on Earth.

Question c) Drought may result due to…….
1) Deforestation 2) Soil conservation
3) Wet weather 4) All of the above
d) Impacts of drought include……
1) Forest fires 3) loss of wetland
2) poverty 4) all of the above
Answer: c) 1) Deforestation
Answer: d) 4) all of the above
In simple words: Deforestation causes less rainfall leading to drought, which causes severe environmental and economic losses.

Exam Tip: Understand how ecological balance prevents droughts and floods.

Question Q.2 Match the following columns:
(i) Drought (a) Results from heavy rain or melting snow
(ii) Deforestation (b) Level of ground water
(iii) Water table (c) Results from no rainfall for a year or more
(iv) Flood (d) Destruction of forest by cutting down trees on a large scale
Answer: (i) -> (c), (ii) -> (d), (iii) -> (b), (iv) -> (a)
In simple words: Matching water-related terms with their correct descriptions.

Exam Tip: Water table refers to the upper limit of groundwater level.

Question Q.3 Answer in one word-
(i) Loss of water by plant leaves.
(ii) Guiding rain water to reach underground.
(iii) Formation of clouds.
(iv) Water conservation strategy based on “catch water where it falls.”
Answer: (i) Transpiration
(ii) Rainwater harvesting (or Groundwater recharge)
(iii) Condensation
(iv) Rainwater harvesting
In simple words: Key hydrological terms in one word.

Question Q.1. Write ‘L’ for Luminous and ‘NL’ for Non-luminous:
(i) Sun
(ii) Radium
(iii) Shoe
(iv) Painting
(v) Lighted Torch
(vi) Electric light
Answer: (i) L
(ii) L (emits light due to radioactivity)
(iii) NL
(iv) NL
(v) L
(vi) L
In simple words: Objects that produce their own light are luminous, others are non-luminous.

Exam Tip: The moon is non-luminous as it reflects sunlight.

Question Q.2. State True or False:
(i) The image formed in pin hole camera is of same size as the object.
(ii) Shadow gives an accurate picture of the shape of the object.
(iii) Shadows can be obtained only on a screen.
(iv) A burning candle is a luminous object.
(v) Light travels along a straight line.
(vi) Mirrors show the reflection of your face.
(vii) We see the moon because it is a luminous body.
Answer: (i) False (Image is usually diminished or enlarged depending on distance)
(ii) False (Shadow only shows the outline, not details)
(iii) True
(iv) True
(v) True
(vi) True
(vii) False (Moon reflects sunlight)
In simple words: Test of basic properties of light, shadows, and reflections.

Exam Tip: Shadows only reveal silhouettes, not colors or internal details.

Question Q.3. Fill in the blanks-
(i) In a plane mirror __________ image is formed.
(ii) When light hits opaque objects ___________ are formed.
(iii) Image formed by pin hole is __________ & __________ in size.
(iv) The pin hole camera is based on the fact that light travels in __________.
(v) Image of an object as seen in a __________ cannot be obtained on a screen.
(vi) The _________ of an object can be longer or shorter in size as compared to the object.
Answer: (i) virtual (and erect)
(ii) shadows
(iii) real (or inverted), diminished
(iv) straight lines (rectilinear propagation)
(v) plane mirror
(vi) shadow
In simple words: Summary of mirror reflections and shadow characteristics.

Exam Tip: Pin-hole camera images are inverted and smaller than the actual object.

Question Q.4. Match the following-
(i) Moon (a) Opaque
(ii) Sun (b) Non- luminous
(iii) Brick (c) Transparent
(iv) Mirror (d) Luminous
(v) Tracing paper (e) Translucent
(vi) Clear glass
Answer: (i) -> (b)
(ii) -> (d)
(iii) -> (a)
(iv) -> (a) (or reflecting surface, but classified as opaque here)
(v) -> (e)
(vi) -> (c)
In simple words: Categorizing materials based on their interaction with light.

Exam Tip: Clear glass is transparent, tracing paper is translucent, brick is opaque.

Question Q.5. Give one word for the following-
(i) Dark patch behind an opaque object ___________
(ii) Instrument used to see around corners ___________
(iii) Sideways inversion in plane mirror ____________
(iv) An object which does not emit light ___________
(v) An object which allows part of light falling on it, to pass through ______
Answer: (i) Shadow
(ii) Periscope
(iii) Lateral inversion
(iv) Non-luminous object
(v) Translucent object
In simple words: Single-term definitions for optical phenomena.

Question Q.6. Tick the right answer-
(i) To get a shadow, we need
(a) Only a source of light & a screen
(b) Only an opaque object
(c) Both (i) and (ii)
(d) Neither (i) nor (ii)
Answer: (c) Both (i) and (ii)
Forming a shadow requires a light source, an opaque object, and a screen.
In simple words: All three elements (source, object, screen) are essential for a shadow.

Exam Tip: Never forget that a screen is required to view a shadow.

Question (ii). The image formed by a plane mirror
(a) Is an erect image
(b) Is of same size as that of object
(c) Shows an interchange of right and left
(d) Shows all above characteristics
Answer: (d) Shows all above characteristics
Plane mirror images are erect, same size, and laterally inverted.
In simple words: A plane mirror creates an upright, equal-sized, laterally inverted image.

Exam Tip: Plane mirror properties are frequently asked in exams.

Question (iii). A pin hole camera produces-
(a) An erect and enlarged image
(b) Inverted and diminished image
(c) Inverted and enlarged image
(d) Erect and diminished image
Answer: (b) Inverted and diminished image
Due to the rectilinear propagation of light, rays cross at the pinhole creating an upside-down (inverted) and smaller image.
In simple words: The image in a pinhole camera is upside down and smaller than the object.

Exam Tip: Pinhole camera images are always real and inverted.

Assignment (Fibre to Fabric)

Question Q.4. Study the chart given below:-
Which could be the processes 1 and 2 in the manufacture of cotton fabric?
(a) 1- spinning, 2- weaving
(b) 1- ginning, 2- spinning
(c) 1- deying, 2- weaving
(d) 1- knitting, 2- weaving
Answer: (a) 1- spinning, 2- weaving
Fibres are converted into yarn by spinning (1), and yarn is converted into fabric by weaving or knitting (2).
In simple words: Fibres spin into yarn, and yarn weaves into fabric.

Exam Tip: Sequence: Fibre -> Yarn -> Fabric.

Question Q.5. Identify the fabric in the following:
(i) shawl (ii) saree
(iii) muffler (iv) socks
(v) mosquito net (vi) curtains
Answer: (i) Wool / Pashmina
(ii) Silk / Cotton / Chiffon
(iii) Wool / Acrylic
(iv) Wool / Cotton / Synthetic blend
(v) Nylon / Cotton net
(vi) Cotton / Synthetic fabric
In simple words: Common materials used for various clothing and household items.

Exam Tip: Shawls are typically made of wool, whereas mosquito nets use fine synthetic netting like nylon.

Question Q.6. Name the following:-
(i) Two types of natural fibres.
(ii) Examples of unstitched fabrics used even today.
(iii) States where cotton is grown.
(iv) Conditions required for growing cotton.
(v) States where jute is grown.
(vi) Devices used for spinning.
(vii) Devices used for weaving.
(viii) Materials used by early people to cover their bodies.
(ix) Fibre cultivated in Egypt near river Nile.
(x) Items made from coir.
(xi) Person who popularized the use of charkha.
Answer: (i) Plant fibres and Animal fibres
(ii) Saree, dhoti, lungi, turban
(iii) Gujarat, Maharashtra, Punjab
(iv) Black soil and warm climate
(v) West Bengal, Bihar, Assam
(vi) Takli (hand spindle), Charkha, spinning machine
(vii) Handlooms, power looms
(viii) Animal skin, large leaves, bark of trees
(ix) Flax
(x) Ropes, mats, mattresses, floor coverings
(xi) Mahatma Gandhi
In simple words: Basic facts regarding fibres, historical clothing, and manufacturing tools.

Exam Tip: Cotton thrives best in black soil and warm weather.

Assignment (Sorting Materials into Groups)

Question Q.1. Fill in the blanks;
(i) Materials that are difficult to compress are called ___________.
(ii) Vinegar is ____________ in water.
(iii) Insoluble substances do not _____________ in water.
(iv) Metal key ___________ in water whereas _____________ floats on water.
(v) Butter is a ___________ object.
(vi) __________ is the hardest known substance found in nature.
(vii) We can feel the presence of ___________ but cannot touch it.
(viii) A silk saree is ___________ to touch whereas a jute bag is __________ to touch.
(ix) Oil and water are examples of ___________ liquids.
(x) ____________ is the hardest substance known in nature.
Answer: (i) hard materials
(ii) soluble (miscible)
(iii) dissolve
(iv) sinks, plastic ball (or wood)
(v) translucent/soft
(vi) Diamond
(vii) air
(viii) smooth, rough
(ix) immiscible
(x) Diamond
In simple words: Properties of materials including hardness, solubility, and transparency.

Exam Tip: Diamond is universally recognized as the hardest natural substance.

Question Q.2. State True or False for the following:-
(i) Light can pass through the palm of a human being.
(ii) Wood is an opaque object.
(iii) Soft substances can be compressed easily.
(iv) Ice sinks in water.
(v) Lemon juice mixes well with oil.
(vi) Gases do not have a definite shape.
(vii) Plastics are lustrous materials whereas metals are non lustrous materials.
Answer: (i) False
(ii) True
(iii) True
(iv) False (Ice floats on water because it is less dense than water)
(v) False (Lemon juice mixes with water, not oil)
(vi) True
(vii) False (Metals are lustrous, plastics are non-lustrous)
In simple words: Verification of physical properties of matter.

Exam Tip: Ice floats on water because solid water (ice) is less dense than liquid water.

Question Q.4. Write ‘S’ for soluble and ‘IS’ for insoluble:
(a) Coconut oil ……….
(b) Lemon ……….
(c) Lemon juice ……….
(d) Sand ……….
(e) Wood ……….
(f) Finger ring ……….
(g) Rasna ……….
(h) Milk ……….
Answer: (a) IS (immiscible/insoluble)
(b) IS (as whole fruit)
(c) S
(d) IS
(e) IS
(f) IS
(g) S
(h) S (miscible)
In simple words: Identifying whether substances dissolve in water.

Question (iv). Glass is an example of
(a) Transparent object
(b) Opaque object
(c) Translucent object
(d) Both (a) and (c)
Answer: (a) Transparent object
Clear glass allows light to pass through completely.
In simple words: Ordinary glass is transparent.

Exam Tip: Transparent materials permit clear vision through them.

Question (v). Which one is not matter
(a) Water
(b) Pen
(c) Petrol
(d) Feelings
Answer: (d) Feelings
Matter has mass and occupies space; feelings do not.
In simple words: Emotions and feelings are not physical matter.

Question (vi). A material that disappears in water
(a) Sand
(b) Salt
(c) Saw dust
(d) Stone
Answer: (b) Salt
Salt dissolves completely in water, forming a clear solution.
In simple words: Soluble substances like salt dissolve and disappear in water.

Exam Tip: Solutes dissolve to form homogeneous solutions.

Assignment (Air Around Us)

Question Q.1. Match the columns:
(i) Burning 1. carbon dioxide
(ii) Photosynthesis 2. oxygen
(iii) Wind mill 3. oxygen
(iv) Inhale 4. plant
(v) Exhale 5. wind
Answer: (i) -> 2 or 1 (Burning requires oxygen and releases carbon dioxide)
(ii) -> 4 (Photosynthesis is performed by plants)
(iii) -> 5 (Windmill runs on wind)
(iv) -> 2 (Inhaling takes in oxygen)
(v) -> 1 (Exhaling releases carbon dioxide)
In simple words: Matching life and atmospheric processes with their key components.

Exam Tip: Respiration and burning both consume oxygen.

Question Q.2. Fill in the blanks-
(i) Food is prepared by plants ___________ by the process of ___________.
(ii) Increased humidity means increased presence of __________ in the air.
(iii) The percentage of carbon dioxide in the air is ___________.
(iv) __________ and ___________ are noble gases.
(v) Dissolved oxygen in water is the life saver of __________ animals.
(vi) Solubility of gases ___________ on heating.
(vii) Air occupies __________ and has mass.
Answer: (i) glucose/food, photosynthesis
(ii) water vapour
(iii) 0.03 percent
(iv) Helium, Neon (or Argon, Krypton, Xenon, Radon)
(v) aquatic
(vi) decreases
(vii) space
In simple words: Facts about air composition, humidity, and gas solubility.

Question Q.3. State true or false for the following-
(i) As we go higher, the atmosphere gets thicker.
(ii) Like any other matter, air cannot be compressed easily.
(iii) Oxygen is the largest component of air.
(iv) The concentration of CO2 is more in polluted areas.
(v) Air is a compound.
Answer: (i) False (Air gets thinner with altitude)
(ii) False (Gases are easily compressible)
(iii) False (Nitrogen is the largest component at 78%)
(iv) True
(v) False (Air is a mixture, not a compound)
In simple words: Air is a mixture and gases are easily compressible.

Question Q.4. Answer in one word-
(i) Gas with maximum concentration in air.
(ii) Gas released by plants during respiration.
(iii) Device used by mountaineers for helping in breathing.
(iv) Process of burning of food by the body to release energy.
Answer: (i) Nitrogen
(ii) Carbon dioxide
(iii) Oxygen cylinder
(iv) Respiration
In simple words: Quick identification of gases and biological processes.

Question Q.1. Name the following:
(i) Process used to separate grains from stalk.
(ii) Process of separating tea leaves from tea.
(iii) The method of separating heavy and light components of a mixture by blowing air.
(iv) Method of separating large-sized impurities from rice.
(v) Method used by farmers to separate husk from grain.
(vi) Apparatus used to separate two immiscible liquids
(vii) Method used in dairies to separate cream from milk.
(viii) Process used to separate salt from sea water
(ix) Two materials that can be used as filters are
Answer: (i) Threshing
(ii) Filtration
(iii) Winnowing
(iv) Handpicking
(v) Winnowing
(vi) Separating funnel
(vii) Churning (Centrifugation)
(viii) Evaporation
(ix) Filter paper, strainer (or cotton cloth)
In simple words: Standard methods of separating various mixtures.

Question Q.2. Match the process with the mixture:
(i) Churning 1. stones / pulses
(ii) Evaporation 2. solid paneer / water
(iii) Filtration 3. water /salt
(iv) Handpicking 4. milk / butter
(v) Sieving 5. bran / flour
Answer: (i) -> 4
(ii) -> 3
(iii) -> 2
(iv) -> 1
(v) -> 5
In simple words: Matching separation techniques with appropriate mixtures.

Question Q.3. Fill in the blanks:
(i) Few drops of lemon juice added to milk gives …………………………..
(ii) A mixture of sawdust and water can be separated by ………………………
(iii) Filtration can be done by using ……………………….. paper.
(iv) Settling of heavier component in a mixture is called ……………………
(v) Evaporating salt solution leaves ………………… at the bottom of the beaker.
(vi) Common salt is obtained from …………………………
(vii) ………………. is used to remove impurities from flour before preparing the dough.
Answer: (i) paneer (curdling/solid cottage cheese)
(ii) filtration
(iii) filter
(iv) sedimentation
(v) salt crystals (residue)
(vi) sea water (or saline water/brine)
(vii) Sieve
In simple words: Filling in missing separation and chemical reaction terms.

Question Q.5. Tick (√) the only correct choice
(i) The property used in separating a mixture of two solids by winnowing is-
(a) Difference in weight
(b) Difference in colour
(c) Difference in size
(d) All of the above
Answer: (a) Difference in weight
Winnowing uses wind to blow away lighter husk particles from heavier grain seeds.
In simple words: Lighter and heavier components are separated by wind based on weight.

Question (ii). Changing a liquid into its vapour state on its surface is called-
(a) Boiling
(b) Sublimation
(c) Evaporation
(d) All of these
Answer: (c) Evaporation
Surface vaporization at any temperature is evaporation.
In simple words: Evaporation turns liquid into vapour at surfaces.

Question (iii). Method used to separate a mixture of two immiscible liquids-
(a) Separating funnel
(b) Decantation
(c) Sedimentation
(d) Evaporation
Answer: (a) Separating funnel
Immiscible liquids form distinct layers and are separated via a separating funnel.
In simple words: A separating funnel isolates liquids that do not mix.

Question (iv). Process used to separate pebbles
(a) Sedimentation
(b) Sieving
(c) Winnowing
(d) Any of the above
Answer: (b) Sieving *(or handpicking depending on context, but sieving separates different-sized solids)*
In simple words: Sieving filters out pebbles and large impurities.

Question (v). The process of separating a liquid from a solid sediment is called
(a) Threshing
(b) Decantation
(c) Winnowing
(d) Filtration
Answer: (b) Decantation
Pouring out liquid without disturbing sediment is decantation.
In simple words: Decantation pours clear liquid off the sediment.

Question (vi). Which of the following mixtures cannot be separated by evaporation
(a) Sea water
(b) Sugar solution
(c) Sand in water
(d) Sugar and salt
Answer: (c) Sand in water
Sand is insoluble and is separated by filtration/sedimentation, not evaporation.
In simple words: Insoluble sand is separated by filtration, not evaporation.

Question Q.1. Fill in the blanks:
(i) Boiling the water into its vapour is a …………………………… change.
(ii) Growing old is a ………………………………….change.
(iii) Earthquake is …………………………… change.
(iv) Breaking of glass is a ………………………………change.
(v) A bud turning into a flower cannot be a ………………............. change.
(vi) Change of state is a ……………………….. change.
(vii) Spoiling of food is a …………………………..change.
(viii) Revolution of earth is a ……………………………….change.
(ix) Formation of rust is a ……………………….change.
(x) Formation of curd from milk is a …………………………..change.
(xi) The appearance of Haley’s comet after every 76 yrs is an example of ………… change.
Answer: (i) reversible / physical
(ii) irreversible / slow / permanent
(iii) natural / undesirable / sudden
(iv) physical / irreversible
(v) reversible
(vi) reversible / physical
(vii) chemical / irreversible / undesirable
(viii) periodic / regular
(ix) chemical / irreversible
(x) chemical / irreversible
(xi) periodic
In simple words: Classifying everyday changes into physical/chemical and reversible/irreversible categories.

Question Q.2. State true or false for the following statements-
(i) Cooking of rice is a physical change.
(ii) Rubbing chalk on a black board is a chemical change.
(iii) Souring of milk is a reversible change.
(iv) Floods occur at regular time intervals.
Answer: (i) False (Cooking is a chemical/irreversible change)
(ii) False (Chalk dust remains chalk; it is a physical change)
(iii) False (Souring is irreversible)
(iv) False (Floods are non-periodic and unpredictable)
In simple words: Testing knowledge of physical vs chemical changes.

Question Q.3. Choose the correct answer-
(i) Which of the following involves a fast chemical change?
(a) The burning of a matchstick
(b) The rusting of iron
(c) The ripening of mango
(d) The growth of a plant.
Answer: (a) The burning of a matchstick
Burning happens instantly and creates new substances.
In simple words: Matchsticks burn rapidly, producing ash and gas.

Question (ii). Solubility of a solid in a liquid can be increased by
(a) Increase in temperature
(b) decrease in temperature
(c) both a and b
(d) none of these
Answer: (a) Increase in temperature
Heating a solvent allows more solute to dissolve.
In simple words: Hot water dissolves more sugar or salt than cold water.

Question (iii). Most of the time measuring devices are based on –
(a) Periodic change
(b) Reversible change
(c) Non- periodic change
(d) None of these
Answer: (a) Periodic change
Clocks and watches rely on repeating periodic motions.
In simple words: Clocks measure time using regular, repeating events.

Question (iv). An example of periodic change is-
(a) Appearance of spring
(b) Burning of paper
(c) Growth of a plant
(d) Burning of cracker
Answer: (a) Appearance of spring
Seasons recur regularly in a fixed cycle.
In simple words: Seasons repeat every year in a periodic cycle.

Question (v). Growth of a tree can be classified in many ways except as a:
(a) Slow change
(b) Irreversible change
(c) Chemical change
(d) Physical change
Answer: (d) Physical change
Tree growth involves permanent biological and chemical transformations.
In simple words: Growth is biological and irreversible, not a simple physical change.

Question Q.4. Can the following changes be reversed? Write Yes or No.
(i) Salt dissolving in water ………….
(ii) Blooming of bud into flower ………….
(iii) Stretched rubber band coming back to its normal size ………….
(iv) Melting of ice cream. ………….
Answer: (i) Yes (by evaporation)
(ii) No
(iii) Yes
(iv) Yes (by freezing)
In simple words: Checking whether everyday changes can be undone.

Question Q.3. Choose the correct answer:
a) Study of microbes is termed as-
(i) Zoology (iii) Genetics
(ii) Botany (iv) Microbiology
b) Study of life is termed as-
(i) Physics (iii) Biology
(ii) Chemistry (iv) Physiology
Answer: a) (iv) Microbiology
Answer: b) (iii) Biology
In simple words: Microbiology is the study of microbes, and biology is the study of all life.

Question Q.1. Fill in the blanks:
a) Lion eats only flesh and so, is called _____________.
b) Carbohydrates remain stored in plants as _____________________.
c) Body building food are called _____________.
d) __________ of mustard plant give us oil and leaves are used as ________.
(e) Bees collect ___________ from flowers.
(f) Flesh eating animals are called _______________.
(g) Humans belong to this category of plant and flesh eating animals ___________.
Answer: a) carnivore
b) starch
c) proteins
d) Seeds, sarson ka saag (or leaves for greens)
e) nectar
f) carnivores
g) omnivores
In simple words: Classification of animals based on feeding habits and plant food sources.

Question Q.2. Which is the edible part of the following plant?
a) Rice _____________ b) Sugarcane ____________
c) Strawberry _____________ d) Pea ____________
Answer: a) Seed
b) Stem
c) Fruit
d) Seed
In simple words: Identifying edible parts of various crops.

Question Q.4. Choose the correct answer.
(a) Which of the following is not obtained from plants?
i Butter ii Tea iii Coffee iv Cocoa
(b) Which of the following is not obtained from animals?
i Milk ii Cereals iii Cheese iv Eggs
(c) Cows, Goats and Horses are all
i Omnivores ii Herbivores iii Carnivores iv Scavengers
(d) An ingredient which is neither obtained from plant or animal is
i. Salt ii. Honey iii. Sugar iv. Spices
Answer: (a) i Butter (obtained from milk)
Answer: (b) ii Cereals (obtained from plants)
Answer: (c) ii Herbivores
Answer: (d) i. Salt (mined from earth/sea water)
In simple words: Identifying sources of food items.

Question Q1. Give one word:
a) Protective foods are _____________ and _____________.
b) Meals that provide us all the nutrients in the proper quantities ____________.
c) Food rich in fibres is called _______________.
d) A balanced diet has all the five ____________ present in it.
e) Iodine turns a food sample blue black showing presence of ___________.
f) Fats and carbohydrates are called __________ giving foods.
g) Proteins are called ____________________ foods.
h) Ghee and butter are sources of ___________.
Answer: a) Vitamins, minerals
b) Balanced diet
c) Roughage (dietary fibre)
d) nutrients
e) Starch
f) energy
g) body-building
h) Fats
In simple words: Key nutritional terms and food functions.

Question Q.5. Observe the following activity done with egg white. Label the diagram. The food sample contains
(a) Fat
(b) Protein
(c) Vitamin
(d) None of the above
Answer: (b) Protein
Egg white is rich in protein, which gives a purple color with copper sulphate and caustic soda (Biuret test).
In simple words: Egg white contains protein, turning purple in chemical tests.

Question Q.2. Fill in the blanks :
a) __________ system is found above soil in a plant.
b) Absorption of water in plants take place by _______________
c) Leaves of Opuntia / Cactus gets modified into ________________
d) Weak stems climb up to the support by with the help of ________________
e) Fibrous roots do not have ______________
f) In pitcher plant, _____________are modified for trapping insects.
g) Leaves are green as they contain _______________
h) Tiny pores present on the leaf surface are called ____________
Answer: a) Shoot
b) roots (root hairs)
c) spines
d) tendrils
e) a main taproot (all roots are similar in size)
f) leaves
g) chlorophyll
h) stomata
In simple words: Plant anatomy terms including shoot system, roots, modified leaves, and stomata.

Question Q.4. Tick the correct option:
a) Which plant has a tap root system?
1. Paddy 2. Mustard
3. Maize 4. Wheat
Answer: 2. Mustard
Mustard is a dicot plant possessing a taproot system.
In simple words: Mustard has a prominent taproot.

Question b) Which plant has a fibrous root system?
1. Pea 2. Beans
3. Wheat 4. Neem
Answer: 3. Wheat
Wheat is a monocot with a fibrous root system.
In simple words: Wheat has fibrous roots.

Question c) Which part of potato plant is eaten?
1. Root 2. Leaf
3. Stem 4. None of these
Answer: 3. Stem
Potato is an underground modified stem (tuber).
In simple words: Potato is an underground stem.

Question d) Which of the following function is performed by the root?
1) absorbs water and mineral from the soil
2) anchors the plant
3) checks soil erosion
4) All of the above
Answer: 4) All of the above
Roots perform all these essential functions.
In simple words: Roots anchor plants, absorb water, and bind soil.

Question e) Which of the following function is performed by the stem?
1) It neither bear branches nor leaves
2) It does not transport food made by leaves
3) It keeps plants straight and gives support to the plant
4) All of the above.
Answer: 3) It keeps plants straight and gives support to the plant
Stems provide structural support and transport water and food.
In simple words: The stem supports the plant and conducts water.

Question Q.2. Fill in the blanks:-
a) __________ wastes include materials of plant and animal origin.
b) Pollution causes contamination of natural elements such as _________, _________ and ___________.
c) The waste which is inorganic in nature and cannot be broken down through the action of micro organisms is called ____________.
d) On burning plastic gives out………….. gases.
e) The pulp of paper with rice husk is called …………
f) Red earthworm grind the food in its …………
g) ……………. is a key to happy future. (conservation/preservation)
Answer: a) Biodegradable
b) air, water, soil
c) non-biodegradable waste
d) toxic / harmful
e) handmade paper
f) gizzard
g) conservation
In simple words: Environmental terms regarding waste management and vermicomposting.

Question Q.2. Name the joints used when,
a) A student climbs the stairs
b) A bowler throws a ball to batsman
c) A teacher turns her head
Answer: a) Hinge joint (knee/ankle)
b) Ball and socket joint (shoulder)
c) Pivotal joint (neck)
In simple words: Different joints permit specific body movements.

Question Q.5. Tick the correct option
1. Which of the following is made up of vertebrae?
a) Sternum b) Cartilage
c) Backbone d) None of these
2. Which of the following is formed by the shoulder blades and the collar bones?
a) Backbone b) Shoulder Girdle
c) Sternum d) Humerus
3. Which of the following animal has its body covered with a hard shell?
a) Earthworms b) Fish
c) Snail d) All of these
4. The lungs and heart are protected by…
a) Rib Cage b) Pelvic Girdle
c) Elbow d) Femur
Answer: 1. c) Backbone
Answer: 2. b) Shoulder Girdle
Answer: 3. c) Snail
Answer: 4. a) Rib Cage
In simple words: Skeletal structure and protection of vital organs.

Question Q.1. Fill in the blanks
a) Temperature is the ___________ component of a habitat.
b) ____________ is a water plant.
c) ____________ and ____________ are the main components of any habitat.
Answer: a) abiotic
b) Hydrilla (or Lotus)
c) Biotic, abiotic
In simple words: Habitats comprise living (biotic) and non-living (abiotic) components.

Question Q.4. Answer the following questions:
a) A motor car moves, takes in oxygen and gives out carbon dioxide, consumes fuel but nonetheless is not a living creature. In what ways does it not qualify as a living organism?
b) A student was asked to write seven life processes. He wrote the following six processes. Which life process has he forgotten to write?
Nutrition, Movement, Sensitivity, Growth, Respiration, Reproduction
Answer: a) A car cannot reproduce, grow on its own, respond to stimuli, or possess cellular organization.
b) Excretion
In simple words: Cars lack vital life processes such as reproduction and excretion.