Science for Class 8 ( Science Curiosity ) Worksheet

Multiple Choice Questions (MCQs)

Instruction: Select the correct option for each question.

1. If Earth had never known life, which change in its atmosphere would most likely be true?
   a) High oxygen from photosynthesis
   b) Thick ozone layer formed naturally without oxygen
   c) Very low oxygen and no biologically produced ozone
   d) Same composition as today
2. Which surface feature would most likely be less abundant without life-driven soil formation?
   a) Thick, organic-rich soils
   b) Basaltic rocks
   c) Impact craters
   d) Volcanoes
3. In a lifeless Earth, which gas would most likely be higher due to unbalanced volcanic emissions?
   a) Oxygen (O₂)
   b) Carbon dioxide (CO₂)
   c) Ozone (O₃)
   d) Methane (CH₄) from microbes
4. Without plants and microbes, the long-term carbon cycle would be mainly controlled by:
   a) Photosynthesis and respiration
   b) Weathering, volcanism, and ocean chemistry
   c) Pollination and seed dispersal
   d) Decomposition by fungi
5. Which color would Earth most likely appear from space without life?
   a) Deep blue with green land patches
   b) Mostly brown/grey rocks with blue oceans and white clouds
   c) Entirely green
   d) Mostly white
6. On a lifeless Earth, the nitrogen cycle would be missing its main conversion by:
   a) Lightning only
   b) Microbes (nitrogen fixation/denitrification)
   c) Volcanoes
   d) Wind erosion
7. Which landform signal would likely be more preserved without life?
   a) Rapid soil-covered slopes
   b) Stable, sharp rock outcrops and more exposed craters
   c) Dense root-bound riverbanks
   d) Organic peat bogs
8. Absent life, which ocean characteristic would most likely differ?
   a) Abundant dissolved oxygen from phytoplankton
   b) Strong biological pump transporting carbon to deep ocean
   c) No plankton blooms; chemistry set by abiotic processes
   d) High biodiversity reefs
9. Which protective system would be weaker or absent without life?
   a) Planetary magnetic field
   b) Ozone layer sustained by O₂ from photosynthesis
   c) Plate tectonics
   d) Ocean tides
10. On a lifeless Earth, seasonal changes would mainly be due to:
    a) Migration and leaf fall
    b) Tilt-driven insolation patterns only
    c) Flowering cycles
    d) Plankton blooms

Fill in the Blanks

Instruction: Fill in the blanks with the correct word based on the chapter.

1. Without photosynthesis, atmospheric __________ would remain very low and ozone would be weak.
2. In a lifeless world, carbon would build up as __________ from volcanic emissions.
3. Soils would be thin and largely mineral because there is no input of __________ matter.
4. Ocean chemistry would lack a biological __________ that moves carbon to the deep sea.
5. Lightning would be one of the few natural sources converting atmospheric nitrogen, in the absence of __________ fixation by microbes.
6. Land surfaces would show more visible impact __________ without rapid biological weathering and soil cover.
7. Without forests and phytoplankton, Earth’s surface would lack the green __________ of life.
8. Climate would be set mainly by orbital position, volcanism, oceans, and the greenhouse effect, not by __________ feedbacks.
9. The atmosphere, hydrosphere, geosphere, and magnetosphere would still interact, but the __________ would be missing.
10. Satellite images would show bare rock, deserts, ice, clouds, and oceans, but no __________ patterns from crops or forests.

Very Short Answer Questions

Instruction: Answer the following questions in one line.

1. What key atmospheric layer would be weaker without life?
2. How would continents look from space without life?
3. Which major biogeochemical cycles would be missing their main drivers?
4. Would Earth still have plate tectonics without life?
5. What would replace forests in shaping land surfaces?

Short Answer Questions

Instruction: Answer the following questions in 2–3 lines.

1. Explain why oxygen would be scarce on a lifeless Earth.
2. How would oceans differ without marine life?
3. What visual signatures used by satellites to track ecosystems would disappear?
4. Would weather and climate still vary in a lifeless world?
5. How would the carbon cycle be balanced without photosynthesis and respiration?

Match the Following

Instruction: Match Column A with the correct option in Column B.

1. Column A:
   1) Ozone layer
   2) Biological pump
   3) Nitrogen fixation
   4) Humus-rich soil
   5) Green vegetation signal
2. Column B:
   a) Satellite NDVI/green cover from plants
   b) Deep-ocean carbon transport by plankton
   c) Thicker, organic topsoil maintained by decomposers
   d) UV shield formed from atmospheric O₂
   e) Conversion of N₂ to usable forms by microbes

Multiple Choice Questions (MCQs)

Instruction: Select the correct option for each question.

1. What is a habitat?
   a) Only the place where animals hunt
   b) The place and conditions where an organism lives and survives
   c) A community of only plants
   d) Only the climate of an area
2. Which pair correctly shows biotic and abiotic components?
   a) Soil (biotic), fish (abiotic)
   b) Sunlight (biotic), bacteria (abiotic)
   c) Tree (biotic), sunlight (abiotic)
   d) Frog (abiotic), air (biotic)
3. A population is best defined as:
   a) All living and non-living things in an area
   b) Different species living together
   c) Members of the same species in a given area and time
   d) All plants in all habitats
4. Pollination is the transfer of:
   a) Seeds from fruit to soil
   b) Pollen from stamen to carpel
   c) Roots to shoots
   d) Water to leaves
5. Which sequence correctly shows a food chain?
   a) Snake → Eagle → Grasshopper
   b) Grass → Hare → Tiger
   c) Eagle → Snake → Frog → Grasshopper
   d) Frog → Grass → Grasshopper
6. Decomposers like mushrooms and bacteria are important because they:
   a) Produce seeds
   b) Make sunlight
   c) Break down dead matter and recycle nutrients
   d) Stop plant growth
7. In the pond example, removing fish can lead to less plant pollination because:
   a) Fish pollinate flowers directly
   b) Fish eat pollinators
   c) Dragonflies increase and reduce pollinators, lowering pollination
   d) Plants stop growing without fish
8. Producers in an ecosystem are:
   a) Animals that hunt
   b) Plants that make food by photosynthesis
   c) Fungi that decompose
   d) Humans only
9. Which interaction benefits both partners?
   a) Parasitism
   b) Competition
   c) Mutualism
   d) Predation
10. Why are mangroves like the Sundarbans valuable?
    a) Only for tourism
    b) They reduce floods, store carbon, and support biodiversity
    c) They increase storms
    d) They have no role in fisheries

Fill in the Blanks

Instruction: Fill in the blanks with the correct word based on the chapter.

1. The living parts of a habitat are called __________ components.
2. The non-living parts like air, water, soil, and light are __________ components.
3. A group of different populations living and interacting in one area is called a __________.
4. Plants are called __________ because they make their own food.
5. Organisms that eat both plants and animals are called __________.
6. Interconnected feeding relationships form a __________.
7. Organisms like fungi and bacteria that break down dead matter are called __________.
8. The position of an organism in a food chain is its __________ level.
9. Cutting too many trees and pollution can disturb __________ balance.
10. Areas like national parks and sanctuaries are set aside as __________ areas.

Very Short Answer Questions

Instruction: Answer the following questions in one line.

1. Define habitat.
2. What is pollination?
3. Name the three main consumer types.
4. Who are decomposers? Give one example.
5. What is one role of migratory birds?

Short Answer Questions

Instruction: Answer the following questions in 2–3 lines.

1. How are biotic and abiotic components linked in an ecosystem?
2. Why does diversity in a habitat help maintain balance?
3. Explain the pond cascade when fish are removed.
4. How do mangroves protect coasts and climate?
5. Why can overuse of pesticides harm farms long-term?

Match the Following

Instruction: Match Column A with the correct option in Column B.

1. Column A:
   1) Producer
   2) Decomposer
   3) Mutualism
   4) Trophic level
   5) Protected area
2. Column B:
   a) Relationship where both partners benefit (e.g., bees–flowers)
   b) Position of an organism in a food chain
   c) National park/sanctuary conserving habitats
   d) Plant making food via photosynthesis
   e) Mushroom/bacteria recycling nutrients

Multiple Choice Questions (MCQs)

Instruction: Select the correct option for each question.

1. Why can we sometimes see the Moon in the daytime?
   a) The Moon produces its own light
   b) The Moon is closer than the Sun
   c) Moonrise can occur in the afternoon and the Moon reflects sunlight
   d) The Sun is off during the day
2. What causes the phases of the Moon?
   a) Earth’s shadow falling on the Moon every night
   b) Changing relative positions of the Sun, Earth, and Moon
   c) Clouds covering the Moon
   d) Changes in Moon’s shape
3. Which day corresponds to no visible Moon in the sky?
   a) Full Moon (Purnima)
   b) Half Moon
   c) New Moon (Amavasya)
   d) Gibbous Moon
4. In India, the waxing period of the Moon is called:
   a) Krishna Paksha
   b) Shukla Paksha
   c) Dakshinayana
   d) Uttarayana
5. Which statement about eclipses is correct?
   a) Lunar eclipses happen every full Moon
   b) Phases are caused by eclipses
   c) Lunar eclipses can occur only on full Moon day
   d) Solar eclipses can occur only on full Moon day

Fill in the Blanks

Instruction: Fill in the blanks with the correct word based on the chapter.

1. The Indian National (Saka) Calendar begins on __________ March in a normal year.
2. Years divisible by 4 are leap years, with exceptions for century years not divisible by __________.
3. Artificial satellites are human-made objects placed into __________ around Earth.
4. Space junk from old satellites and rockets is called space __________.
5. Vikram Sarabhai is known as the Father of the Indian __________ programme.

Vikram Sarabhai

Very Short Answer Questions

Instruction: Answer the following questions in one line.

1. Why don’t eclipses happen every month?
2. Which phase shows more than half illuminated but not full?
3. How much later does the Moon rise each successive day on average?
4. Name one festival linked to the new Moon.
5. Give one use of artificial satellites.

Artificial Satellites

Short Answer Questions

Instruction: Answer the following questions in 2–3 lines.

1. Explain why the Moon appears to change shape.
2. Differentiate waxing and waning phases.
3. How do lunar, solar, and luni-solar calendars differ?
4. What is the Indian National (Saka) Calendar and when does it start?
5. List two ISRO missions and their focus.

Match the Following

Instruction: Match Column A with the correct option in Column B.

Multiple Choice Questions (MCQs)

Instruction: Select the correct option for each question.

1. Which mirror makes objects appear smaller but gives a wider field of view?
   a) Plane mirror
   b) Concave mirror
   c) Convex mirror
   d) Two-way mirror
2. Looking at the inner (curved inward) side of a shiny spoon, your face appears:
   a) Erect and diminished
   b) Inverted (upside down)
   c) Erect and same size
   d) Erect and magnified at all distances
3. The warning “Objects in mirror are closer than they appear” is written because a convex mirror:
   a) Inverts images
   b) Forms enlarged images
   c) Forms diminished images
   d) Does not follow reflection laws
4. Which statement about a concave mirror is correct?
   a) Always forms erect images
   b) Always forms diminished images
   c) Can form enlarged erect images when object is close
   d) Never focuses light
5. First law of reflection states:
   a) i + r = 90°
   b) i = r
   c) i > r
   d) i < r

Fill in the Blanks

Instruction: Fill in the blanks with the correct word based on the chapter.

1. A concave mirror can form an __________ image when the object is very close.
2. A convex mirror always forms an __________ and __________ image.
3. A convex lens is thicker at the __________ than at the edges.
4. A concave lens is a __________ lens because it spreads light rays apart.
5. The human eye contains a __________ lens that changes shape to focus.

Very Short Answer Questions

Instruction: Answer the following questions in one line.

1. Why do vehicle side-view mirrors use convex mirrors?
2. What is lateral inversion?
3. State the two laws of reflection in words.
4. Which mirror can focus sunlight onto paper?
5. Which lens always gives an erect and diminished image?

Lateral Inversion

Short Answer Questions

Instruction: Answer the following questions in 2–3 lines.

1. How does a concave mirror’s image change as the object moves away?
2. Why do convex mirrors make objects seem farther away?
3. Explain why a convex lens can burn paper but a concave lens cannot.
4. How do we know the laws of reflection apply to spherical mirrors?
5. What images do concave and convex lenses form at various distances?

Match the Following

Instruction: Match Column A with the correct option in Column B.

Multiple Choice Questions (MCQs)

Instruction: Select the correct option for each question.

1. Which of the following forms a true (clear) solution with water?
   a) Sand
   b) Sawdust
   c) Sugar
   d) Chalk powder
2. In a salt-water solution, which is the solvent?
   a) Salt
   b) Water
   c) Both are solvents
   d) Neither is solvent
3. Air is a gaseous solution in which the major component (solvent) is:
   a) Oxygen
   b) Nitrogen
   c) Carbon dioxide
   d) Argon
4. As more salt is added to a fixed amount of water, undissolved salt starts settling. The solution has become:
   a) Dilute
   b) Unsaturated
   c) Saturated
   d) Concentrated but unsaturated
5. Which statement about dilute vs. concentrated is correct?
   a) They are absolute, fixed terms
   b) They are comparative terms for amount of solute
   c) They depend only on solvent type
   d) They only apply to gases
6. For most solid solutes in water, increasing temperature generally:
   a) Decreases solubility 
   b) Increases solubility
   c) Has no effect
   d) Makes solution non-uniform
7. The solubility of gases in water generally:
   a) Increases with temperature
   b) Is highest at boiling point
   c) Is unaffected by temperature
   d) Decreases with temperature
8. If in a syrup (chashni) sugar amount is more than water, the solvent is still:
   a) Sugar, because it is more
   b) Water, because it is liquid and determines state
   c) Both are solvents
   d) Neither is solvent
9. Density is defined as:
   a) Volume per unit mass
   b) Mass per unit volume
   c) Weight per unit mass
   d) Weight per unit volume
10. Which statement explains why ice floats on water?
    a) Ice has more mass
    b) Ice has higher density
    c) Ice has lower density than liquid water
    d) Ice has no mass

Fill in the Blanks

Instruction: Fill in the blanks with the correct word based on the chapter.

1. A solution is a __________ mixture in which components are evenly distributed.
2. In a solid–liquid solution, the solid is the __________ and the liquid is the __________.
3. When no more solute can dissolve at a given temperature, the solution is __________.
4. The maximum amount of solute that can dissolve in a fixed quantity of solvent at a given temperature is called __________.
5. Oxygen dissolves only in __________ quantities in water, yet it is vital for aquatic life.
6. For gases, solubility generally __________ with increase in temperature.
7. Density = __________ / __________.
8. The SI unit of density is __________.
9. When temperature increases, volume tends to increase and density tends to __________ (if mass stays same).
10. Reading liquids in a measuring cylinder is done at the bottom of the __________ for water and colorless liquids.

Very Short Answer Questions

Instruction: Answer the following questions in one line.

1. Define solute and solvent with an example.
2. What happens when a saturated salt solution is heated?
3. Name the major component of air that acts as the solvent.
4. State the formula for density.
5. Which has higher dissolved oxygen: cold water or warm water?

Short Answer Questions

Instruction: Answer the following questions in 2–3 lines.

1. Why does sugar dissolve in water but sand does not form a solution?
2. Explain dilute vs. concentrated solutions with an example.
3. How does temperature affect solubility of solids vs. gases in water?
4. How do you measure the volume of an irregular solid using a measuring cylinder?
5. Why does ice float on water and why is this important for aquatic life?

Match the Following

Instruction: Match Column A with the correct option in Column B.

Multiple Choice Questions

Q.1. Kerosene and Petrol are miscible liquids. The difference between their boiling points is more than 25°C. The two liquids can be separated from each other by _____. 
(a) Simple distillation
(b) Steam distillation
(c) Fractional distillation
(d) Any of these

Q.2. How can a saturated solution be made unsaturated?
(a) By heating the solution
(b) By cooling the solution
(c) By increasing the amount of solute
(d) By centrifugation of the solution

Q.3. The cause of Brownian movement is:
(a) Heat changes in liquid state
(b) Convection currents
(c) Impact of molecules of dispersion medium on on dispersed phase
(d) Attractive forces between the particles of dispersed phase and dispersion medium.

Q.4. In which of the following, dispersed phase is a liquid and dispersion medium is a gas? 
(a) Cloud
(b) Smoke
(c) Gel
(d) Soap bubble

Q.5. At room temperature, a non-metal which is a liquid is: 
(a) Sulphur
(a) Bromine
(a) Chlorine
(a) Nitrogen

Fill in the Blanks1. Common salt is _________.

2. A mixture contains more than ______ substance mixed in ______ proportion.
3. Properties of a __________ are different from its constituent elements, whereas a _______ shows the properties of its constituting elements.
4. A solution is defined as a mixture that is_________
5. We can remove salts from a solution by using the process of _________
6. A pure substance has a fixed__________ or ______ at constant temperature.
7. An element is made up of only one kind of _________.
8. Miscible liquids are separated by ________ .
9. Immiscible liquids are separated by using a _______.
10. Filtered tea is a _________ mixture.
11. Alloy is a _______.
12. Sublimation of camphor is a _________ change.
13. Most common chemical change we observe in our routine life is rusting of______.

Very Short Answer Question 

Q.1. Classify the substances given in below figure into elements and compounds

Q.2. Give one example each of homogeneous and heterogeneous mixture.
Q.3. Name the apparatus by which mixture of oil and water can be separated.
Q.4. Is brass a mixture or a compound?
Q.5. What type of solution is an alloy? Liquid solution or solid solution
Q.6. A mixture consisting of two miscible liquids ‘A’ and ‘B’ whose boiling points differ by 50 C can be separated by which process?
Q.7. Give one example of solid- liquid homogeneous mixture.
Q.8. What is a Aqua regia?
Q.9. Which method is used to separate two immiscible liquids?
Q.10. Name two elements which are in liquid state at room temperature? 

Short Answer Types Questions

Q.1. Try segregating the things around you as pure substances or mixtures. 

Q.2. What is meant by a substance? 

Q.3. What type of mixtures are separated by the technique of crystallisation? 

Q.4. What is tyndall effect? Which kinds of solution show it?

Q.5. What is centrifugation? Where it is used?

Q.6. What is crystallization? Where is it used? Why is this better than simple evaporation technique?

Q.7. What is a colloid? What are its various properties?

Q.8. Write a method to separate different gases from air.

Q.9. Explain the following giving examples. 
(a) saturated solution 
(b) pure substance 
(c) colloid 
(d) suspension

Q.10. Write the steps you would use for making tea. Use the words solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.

Crossword Puzzle

Across
1. hydrogen ______ is a color gas with a smell of rotten eggs
5. The major components in solution
6. Melting point and boiling point are _______ properties
7. Two elements are liquid at room temperature are mercury and _______
Down
2. In colloids ,The particles are called the ______ phase and the medium in which they are distributed is called the dispersion medium.
3. amount of solute present per unit volume or mass of the solution or solvent
4. denser particles are forced to the bottom and the lighter particles stay at the top when spun rapid

You can find Worksheets Solutions here: Worksheet Solutions: Is Matter Around Us Pure

Multiple Choice Questions

Q.1. According to ancient philosophers, matter consists of:
(a) Three constituents
(b) Four constituents
(c) Five constituents
(d) Six constituents

Q.2. Dry ice is:
(a) Solid ammonia
(b) Solid carbon dioxide
(c) Solid sulphur dioxide
(d) Normal ice. 

Q.3. Which of the following statements is not correct for liquid state?
(a) Particles are loosly packed in the liquid state
(b) Fluidity is the maximum in the liquid state
(c) Liquids can be compressed
(d) Liquids take up the shape of any container in which these are placed

Q.4. Which of the following will sublime? 
(a) Common salt
(b) Sugar
(c) Camphor
(d) Potassium nitrate

Q.5. When the liquid starts boiling, the further heat energy which is supplied: 
(a) Is lost to the surrounding as such
(b) Increases the temperature of the liquid
(c) Increases the kinetic energy of the particles in the liquid 
(d) Is absorbed as latent heat of vaporisation by the liquid

Fill in the blanks:-1. Matter is made up of small_________.
2. The forces of attraction between the particles are _______ in solids, ______ in liquids and _________ in gases.
3. __________ is the change of gaseous state directly to solid state without going through liquid state, and vice versa.
4. Evaporation causes __________.
5. Latent heat of fusion is the amount of heat energy required to change 1 kg of solid into liquid at its ________.
6. Solid, liquid and gas are called the three _______ of matter.
7. The smell of perfume gradually spreads across a room due to ______.
8. Rapid evaporation depends on the ______ area exposed to the atmosphere.
9. As the temperature of a system increases, the pressure of the gases ______.
10. As the volume of a specific amount of gas decreases, it’s pressure _______.
11. As the temperature of a gas decreases, I’s volume ______.
12. Gas molecules at higher temperatures have more _______ than at cooler temperatures.
13. A sponge has minute ________, in which ________ is trapped.
14. The pressure inside of a sealed tube if you raise the temperature go ______
15. Forces of attraction in liquids are _______ than in solid.
16. Latent heat of ________ is the amount of heat energy required to change 1 kg of solid into liquid at its melting point.

Very Short Answer Questions

Q.1. Name one property which is shown by naphthalene and not by sodium chloride.

Q.2. A rubber band changes its shape when stretched. Can it be regarded as solid?

Q.3. Gases can be compressed but solids cannot. Explain.

Q.4. Kelvin scale of temperature is regarded better than the Celsius scale. Assign reason.

Q.5. What happens to the heat energy which is supplied to the solid once it has started melting?

Q.6. The freezing point of water is 0°C. What is the corresponding temperature on the Kelvin scale?

Q.7. Are the melting point temperature of the solid state and the freezing point temperature of the liquid state of a substance different?

Q.8. A substance is in liquid state at room temperature and changes into gas upon heating. What will you call its gaseous state?

Q.9. When a crystal of copper sulphate is placed at the bottom of a beaker containing water?

Q.10. The boiling point of ethyl alcohol is 78°C. What is the corresponding temperature on kelvin scale?

Crossword Puzzle

Across
1. BEC stands for Bose-Einstein-______

3. The state consists of super energetic and super excited particles

8. Conversion of solid to vapour is called ______
Down
2. This is the phenomenon of change of a liquid into vapours at any temperature below its boiling point
4. SI unit of Temperature
5. CNG stands ____ natural gas
6. It is the amount of water vapour present in air.
7. LPG stands for ______petroleum gas. 

You can find Worksheet Solutions here: Worksheet Solutions: Particulate Nature of Matter

Multiple Choice Questions (MCQs)

Instruction: Select the correct option for each question.

1. Pressure is defined as:
   a) Force × area
   b) Force / area
   c) Area / force
   d) Mass × acceleration
2. Why do broader bag straps feel more comfortable than narrow ones for the same load?
   a) They reduce the force
   b) They increase pressure
   c) They decrease pressure by increasing area
   d) They change the weight
3. SI unit of pressure is:
   a) Newton (N)
   b) Joule (J)
   c) Pascal (Pa)
   d) Watt (W)
4. Liquid pressure at a point depends mainly on:
   a) Shape of container
   b) Color of liquid
   c) Height (depth) of the liquid column
   d) Total volume of liquid
5. Which activity shows that liquids exert pressure on the walls?
   a) Balloon inflating
   b) Water jetting sideways from holes in a bottle
   c) Magnet attracting iron
   d) Ice melting
6. Atmospheric pressure is the pressure exerted by:
   a) Water only
   b) Rocks of Earth
   c) Air around us in all directions
   d) Only wind
   Atmospheric Pressure
7. Air moves from a region of:
   a) Low pressure to high pressure
   b) High pressure to low pressure
   c) High temperature to low temperature only
   d) Low density to high density only
8. During the day at the coast, a sea breeze blows because:
   a) Sea heats faster than land
   b) Land heats faster; air rises over land creating low pressure
   c) Air pressure over sea is always low
   d) Earth stops rotating
9. High-speed winds between two hanging balloons make them move closer because:
   a) Gravity increases
   b) Pressure between them increases
   c) Pressure between them decreases due to fast air
   d) They gain electric charge
10. Lightning is produced when:
    a) Sun heats clouds
    b) Charges in clouds and ground discharge suddenly
    c) Wind speed becomes zero
    d) Air becomes very cold

Fill in the Blanks

Instruction: Fill in the blanks with the correct word based on the chapter.

1. Pressure = __________ / area.
2. Overhead water tanks are placed high to increase water __________ in the pipes.
3. 1 pascal (Pa) equals 1 __________ per square metre.
4. Liquids exert pressure at the bottom and also on the __________ of a container.
5. At sea level, typical atmospheric pressure is about 1,013 __________ or 1,013 __________.
6. Air flows from regions of high pressure to regions of __________ pressure.
7. Daytime coastal wind from sea to land is called a __________ breeze.
8. Lightning conductors safely carry electric charge into the __________.
9. The calm, low-pressure center of a cyclone is called the __________.
10. A sudden rise of sea water pushed by cyclone winds onto land is called a storm __________.

Cyclone

Very Short Answer Questions

Instruction: Answer the following questions in one line.

1. Why are dam walls broader at the base?
2. Why aren’t we crushed by atmospheric pressure?
3. What causes a sea breeze?
4. What simple safety rule helps prevent roofs from blowing off in storms?
5. What is a thunderstorm?

Dams are build borader at Base

Short Answer Questions

Instruction: Answer the following questions in 2–3 lines.

1. Explain, with an example, how area affects pressure in daily life.
2. How does height of a liquid column affect pressure? Mention one application.
3. Describe briefly how winds are formed.
4. How does lightning form inside storm clouds?
5. Why are cyclones dangerous? Give two reasons.

Match the Following

Instruction: Match Column A with the correct option in Column B.

Force

Q1. Multiple Choice Questions (MCQs)

Instruction: Select the correct option for each question.

1. In science, a force is defined as:
   a) Only a push
   b) Only a pull
   c) A push or a pull
   d) Energy of motion
2. Which of these is NOT an effect of force?
   a) Change of shape
   b) Change of direction
   c) Production of light
   d) Start/stop motion
3. Forces always involve:
   a) Only one object
   b) Interaction between two objects
   c) Only moving objects
   d) Only heavy objects
4. The SI unit of force is:
   a) Joule (J)
   b) Watt (W)
   c) Newton (N)
   d) Pascal (Pa)
5. Friction is a force that:
   a) Aids motion
   b) Always increases speed
   c) Opposes motion between surfaces in contact
   d) Acts only in liquids
6. Which is a non-contact force?
   a) Muscular force
   b) Friction
   c) Magnetic force
   d) Push with a stick
7. Gravity is:
   a) Sometimes attractive, sometimes repulsive
   b) Always repulsive
   c) Always attractive
   d) Only acts on Earth
8. Weight is measured in:
   a) Kilogram (kg)
   b) Newton (N)
   c) Meter (m)
   d) Joule (J)
9. An object floats in a liquid when:
   a) Weight > buoyant force
   b) Weight = buoyant force
   c) Weight < buoyant force
   d) There is no gravity

Q2. Fill in the Blanks

Instruction: Fill in the blanks with the correct word based on the chapter.

1. A force is a __________ or a __________.
2. If an object’s speed or direction changes, a __________ has acted.
3. The SI unit of force is the __________ (symbol: N).
4. Friction always acts in a direction __________ to motion.
5. Forces that act without contact are called __________ forces.
6. The force with which Earth pulls objects is called __________.
7. Weight is a __________ and is measured in newtons.
8. The device used to measure weight (force) in newtons is a __________ balance.
9. The upward force exerted by a liquid on an immersed object is called __________ force.
10. An object sinks when its __________ is greater than the buoyant force.

Q3. Short Answer QuestionsInstruction: Answer the following questions in 2–3 lines.

1. How does friction depend on the nature of surfaces?
2. Explain why cycling uphill feels harder than cycling downhill.
3. What does “forces work in pairs” mean?
4. How do we find the least count of a spring balance?
5. Why do streamlined shapes help in air or water?

Q4. Match the Following

Instruction: Match Column A with the correct option in Column B.

Q5. Application/Reasoning (Short Problems)

Instruction: Answer the following briefly in 2–3 lines.

1. A wooden block is pushed on a rough table and stops after some distance. Why?
2. A 1 kg object has a weight of about 10 N on Earth. What will be its weight on the Moon (g ≈ 1.6 m/s²)?
3. A spring balance has marks 0 to 5 N with 10 equal divisions between each newton. What is its least count?
4. Two balloons rubbed with wool repel each other. Which force is acting and why?
5. A stone sinks in water but a sealed empty plastic bottle floats. Why?

Check the solutions of worksheet here.

Q1. Multiple Choice Questions (MCQs)

Instruction: Select the correct option for each question.

1. What did Oersted discover in 1820?
   a) Heating effect of current
   b) Electric charge of Earth
   c) Magnetic effect of electric current
   d) Structure of dry cell
2. Which instrument can detect the magnetic field around a current-carrying wire?
   a) Vernier caliper
   b) Magnetic compass
   c) Thermometer
   d) Barometer
3. An electromagnet is:
   a) A permanent magnet made of steel
   b) A coil with an iron core that becomes a magnet when current flows
   c) A bar magnet with fixed poles
   d) A coil without any core
4. Which change will increase the strength of an electromagnet?
   a) Using fewer turns of wire
   b) Reducing current
   c) Inserting a soft iron core
   d) Removing the battery
5. Lifting electromagnets are used mainly to:
   a) Measure current
   b) Lift and move heavy steel in scrap yards
   c) Store electrical energy
   d) Heat metals
6. When current passes through a nichrome wire, it becomes hot due to:
   a) Absence of resistance
   b) Magnetic shielding
   c) Cooling effect of current
   d) Heating effect of electric current
7. Which factor increases heat in a wire for the same time?
   a) Thicker wire and less current
   b) Shorter wire and less current
   c) Longer, thinner wire with more current
   d) No resistance in wire
8. In a simple voltaic (galvanic) cell, electricity is produced by:
   a) Chemical reactions between metals and electrolyte
   b) Friction 
   c) Magnetic induction
   d) Solar energy
   
   Dry Cell
9. In a dry cell, the negative terminal is the:
   a) Zinc container
   b) Carbon rod 
   c) Electrolyte paste
   d) Air gap
10. Lithium-ion batteries are:
    a) Single-use only
    b) Not suitable for recharging
    c) Only for torches and clocks
    d) Rechargeable and used in phones/laptops

Q2. Fill in the Blanks

Instruction: Fill in the blanks with the correct word based on the chapter.

1. A current-carrying conductor produces a __________ field around it.
2. The deflection of a __________ needle shows the presence of current nearby.
3. An iron nail wrapped with a current-carrying coil becomes an __________.
4. Reversing the direction of current reverses the __________ of an electromagnet.
5. The heating of a wire due to current is called the __________ effect of electric current.
6. __________ wire is used as a heating element because it has high resistance.
7. A device that produces electricity by a chemical reaction is called an electric __________.
8. In a dry cell, the electrolyte is a moist __________.
9. In the lemon battery, the lemon juice acts as an __________.
10. Multiple cells connected together form a __________.

Q3. Very Short Answer Questions (1 line)

Instruction: Answer the following questions in one line.

1. What simple observation shows the magnetic effect of current?
2. Name any one factor that increases the strength of an electromagnet.
3. What happens to an electromagnet when the current is switched off?
4. What is resistance?
5. Which terminal is at the center of a dry cell?

Q4. Short Answer Questions

Instruction: Answer the following questions in 2–3 lines.

1. State Oersted’s finding and its importance.
2. How can you make a simple electromagnet at home?
3. Mention two ways to increase the heat produced in a wire.
4. What is the basic structure of a dry cell?
5. How can you light an LED with lemons?

Q5. Match the Following 

Instruction: Match Column A with the correct option in Column B.

Ans: 

1. Oersted — c) Current creates magnetic field
   He discovered the magnetic effect of electric current.
2. Electromagnet — e) Coil with iron core works only when current flows
   It becomes magnetic only when powered.
3. Nichrome — a) Heating element material
   Nichrome’s high resistance makes it ideal for heaters.
4. Lifting crane magnet — d) Switchable industrial magnet
   Used to lift/drop heavy steel by switching current ON/OFF.
5. Zinc can (dry cell) — b) Negative terminal
   In a dry cell, the zinc container acts as the negative electrode.