Exam Success Guide

To achieve top scores (98–99%), remember these presentation rules:

1-Mark Questions: Provide direct, precise keyword answers.
2-Mark Questions: Limit answers strictly to two clear bullet points or a concise definition with an example.
3-Mark Questions: Utilize comparison tables for differences or write 3 structured points with headings.
5-Mark Questions: Organize into an introduction, step-by-step breakdown or stages, and a conclusive summary or labeled application.

SCIENCE MODEL QUESTION PAPER

Covered Topics: Temperature, States of Water, Methods of Separation, and Living Creatures

Time Allowed: 3 Hours Maximum Marks: 100

SECTION A: Objective & Very Short Answer Questions (20 Marks)

Q1. Name the scale of temperature whose SI unit is named in honour of the scientist who developed it.

Ans: Kelvin scale (unit: kelvin)

Q2. What colour is alcohol generally dyed in a laboratory thermometer to make it easily visible?

Ans: Red

Q3. Name the specific type of thermometer used for measuring human body temperature.

Ans: Clinical thermometer

Q4. What is the usual temperature range marked on a standard laboratory thermometer?

Ans: -10°C to 110°C

Q5. What term is used to describe the amount of water vapour present in the air?

Ans: Humidity

Q6. What is the process of conversion of a liquid into its solid state called?

Ans: Freezing

Q7. State True or False: "Water vapour present in the air is visible to our naked eyes."

Ans: False (Water vapour is invisible; tiny droplets make steam visible)

Q8. What is the process of conversion of liquid water into its gaseous state called?

Ans: Evaporation

Q9. Name the traditional bamboo tray used in farming for winnowing.

Ans: Soop

Q10. Which method of separation is commonly used to separate tea leaves from brewed tea?

Ans: Filtration

Q11. Name a well-known natural water body in Rajasthan that contains common salt.

Ans: Sambhar Lake

Q12. State True or False: "A mixture of mustard oil and lemon water can be separated by decantation."

Ans: True

Q13. What are the substances that get attracted towards a magnet called?

Ans: Magnetic substances

Q14. Name the tiny pores on the surface of leaves that help plants take air in and out.

Ans: Stomata

Q15. What is the biological process of producing new individuals of one's own kind called?

Ans: Reproduction

Q16. Name the insectivorous plant featuring saucer-shaped leaves with sticky hair-like projections.

Ans: Drosera

Q17. State True or False: "Direct sunlight is essential for the germination of all types of seeds."

Ans: False

Q18. What are the two distinct worm-like developmental stages found in the life cycle of a mosquito called?

Ans: Larva and pupa

Q19. What is the jelly-like substance containing a cluster of frog eggs in a pond called?

Ans: Spawn

Q20. Who was the eminent Indian scientist famously known as the 'Weather Woman of India'?

Ans: Anna Mani

SECTION B: Short Answer Questions (20 Marks)

Q21. Why is mercury being replaced by digital thermometers in modern clinical usage?

1. Mercury is an extremely toxic substance and hazardous to dispose of if a thermometer breaks.
2. Digital thermometers pose no chemical risk and have easy-to-read numeric displays.

Q22. What happens to the temperature of water while it is boiling, or ice while it is melting?

1. The temperature remains constant during the entire process of melting or boiling.
2. The supplied heat is utilized for changing the state rather than raising the temperature.

Q23. Define condensation and give one natural example.

Definition: The process of conversion of water vapour into its liquid state.
Example: Formation of dew drops on plants during cold mornings.

Q24. Why does handpicking prove to be a convenient method of separation in daily life?

1. It is useful when unwanted impurities are present in small quantities.
2. It relies on visible differences in particle size, shape, and colour without needing special equipment.

Q25. How is a sieve useful in separating solid-solid mixtures?

1. Sieving separates components based on differences in their particle sizes using pores.
2. Smaller particles pass through the holes while larger impurities or bran remain on top.

Q26. State two reasons why living beings require food (nutrition).

1. Food provides essential energy required to perform vital life activities.
2. It supplies nutrients necessary for bodily growth and development.

Q27. Define stimulus with a suitable example.

Definition: Any change or event in the environment that prompts living beings to respond.
Example: Folding of leaves in a touch-me-not (chhui-mui) plant when touched.

Q28. Why do seeds require water during the germination process?

1. Water softens the tough outer seed coat.
2. It activates biochemical processes enabling the tiny embryo inside to develop into a seedling.

Q29. What is the functional importance of the tail in a tadpole stage of a frog?

1. The tail acts as a primary swimming and propulsion organ in water.
2. It helps the aquatic tadpole maneuver efficiently before transforming into a leg-bearing froglet.

Q30. Why is stagnant water discouraged around residential areas regarding mosquito control?

1. Female mosquitoes lay eggs directly in standing, stagnant water bodies.
2. It serves as an active breeding ground for mosquito larvae and pupae to complete their life cycle.

SECTION C: Medium Answer Questions (30 Marks)

Q31. Describe the correct procedure for measuring the temperature of warm water using a laboratory thermometer.

Immersion: Dip the thermometer into the water so the bulb is fully submerged without touching the beaker's base or sides.
Vertical Alignment: Hold the instrument strictly upright and vertical, avoiding any tilt.
Reading: Read the temperature directly while the bulb remains immersed, keeping your eyes level with the liquid column.

Q32. Outline the experiment that proves water droplets on an ice tumbler originate from condensation rather than seeping.

Observation: Water droplets accumulate on the outer surface of a glass tumbler filled with ice-cold water.
Weighing Evidence: Tracking total mass on a digital balance shows an increase, proving extra mass comes from outside.
Level Check: Marking the internal water level confirms the water level inside does not decrease, verifying it is condensation of atmospheric vapour.

Q33. Differentiate between sedimentation, decantation, and filtration with respective examples.

Process	Description	Example
Sedimentation	Heavier insoluble particles settle down at the bottom.	Mud particles settling in muddy water.
Decantation	Tilting vessel to pour clear liquid above sediment.	Separating clear water from settled mud.
Filtration	Passing mixture through a porous barrier or filter paper.	Separating tea leaves using a strainer.

Q34. Explain the principle of magnetic separation and give a modern application.

Principle: It separates magnetic substances (like iron) from non-magnetic substances using a magnet.
Process: When a magnet is moved through a mixed heap, magnetic particles get attracted and stick to it.
Industrial Application: Recyclers and cranes use large electromagnets to extract scrap iron from industrial waste heaps.

Q35. List the core characteristics that distinguish living beings from non-living things.

Movement & Growth: Living creatures show autonomous movement and grow permanently in size.
Respiration & Excretion: They take in air for respiration and excrete metabolic waste products.
Stimulus & Reproduction: They respond to environmental stimuli and reproduce offspring to sustain life.

Q36. Discuss the essential conditions for seed germination, focusing on air and water.

Role of Water: Softens the seed coat and hydrates internal cells, triggering metabolic growth.
Role of Air: Provides necessary oxygen residing in soil pore spaces for cellular respiration.
Light Requirement: Most seeds germinate without light, though sunlight becomes essential later for seedling growth.

Q37. Describe how plant roots and shoots respond to gravity and light based on experimental findings.

Shoot Growth: Shoots grow upwards against gravity and bend toward the direction of light (phototropism).
Root Growth: Roots consistently grow downwards into the soil regardless of plant orientation (geotropism).
Inverted Response: Even if a seedling is inverted, shoots curve upward and roots curve downward.

Q38. Outline the four stages of a mosquito's life cycle and explain how kerosene oil interrupts it.

Four Stages: Egg → Larva → Pupa → Adult mosquito.
Interruption Mechanism: Kerosene oil creates an airtight film over stagnant water surfaces.
Outcome: Larvae and pupae cannot access atmospheric air for breathing, causing them to suffocate and die.

Q39. Match the following separation techniques with their descriptions:

1. Threshing → Beating harvested stalks to separate grains
2. Winnowing → Using wind to blow away lighter husk from grains
3. Sieving → Separating solid components using a sieve based on particle size

Q40. Explain the major developmental stages in the life cycle of a frog.

Spawn (Eggs): Jelly-like clusters laid by female frogs in water bodies.
Tadpole Stage: Hatches with a tail and gills, swimming in water and developing hind legs.
Froglet Stage: Grows front legs, develops lungs, and starts absorbing its tail.
Adult Frog: Tail vanishes completely, enabling amphibious life on land and in water.

SECTION D: Long Answer Questions (30 Marks)

Q41. Explain how temperature scales are structured and how conversion to Kelvin is performed.

Celsius Scale: Uses degree Celsius (°C) where normal human body temperature averages around 37.0°C.
Fahrenheit Scale: Uses degree Fahrenheit (°F) where normal body temperature is equivalent to 98.6°F.
Kelvin Scale: Serves as the SI temperature unit denoted by K (no degree sign used).
Conversion Formula: Temperature in Kelvin = Temperature in Celsius + 273.15.

Q42. Discuss the factors affecting the rate of evaporation and explain how evaporation causes a cooling effect.

Exposed Surface Area: A larger exposed surface area (e.g., spreading water in a plate) increases evaporation speed.
Temperature & Wind: Higher ambient heat and increased air movement accelerate evaporation.
Humidity: Higher water vapour content in the air slows down evaporation rates.
Cooling Effect: Evaporation absorbs thermal heat energy from surfaces, creating a cooling sensation (e.g., sweating, earthen pots).

Q43. Outline a step-by-step scientific procedure to separate a mixture of iron nails, sand, common salt, and water.

Step 1 (Magnetic Separation): Pass a magnet through the mixture; the magnetic iron nails stick to it and are separated.
Step 2 (Filtration): Filter the remaining mixture using filter paper. Insoluble sand is retained as residue.
Step 3 (Evaporation): Take the clear salt solution filtrate in a dish and heat it until water evaporates completely.
Outcome: Pure common salt crystals are left behind as solid residue, completing the separation.

Q44. Detail the complete life cycle of a bean plant from seed sowing to the next generation.

Stage I (Seed): Begins with a dormant seed containing an embryo inside a protective seed coat.
Stage II & III (Germination & Leaves): Absorbing water and air leads to sprouting, root/shoot growth, and green leaf development.
Stage IV & V (Flowers & Fruit): Flowers appear, undergo pollination, and mature into pods containing seeds.
Continuity: The parent plant eventually dies, and the harvested seeds give rise to a new generation of plants.

Q45. Compare and contrast the life cycles of a mosquito and a frog, highlighting similarities and habitat transitions.

Similarities: Both undergo complete metamorphosis, begin life as eggs laid in aquatic environments, and feature active immature stages.
Developmental Differences: Mosquitoes progress through Egg → Larva → Pupa → Adult, whereas frogs develop through Spawn → Tadpole → Froglet → Adult.
Adult Habitat Shift: Adult mosquitoes transition into flying aerial insects, while adult frogs become amphibious vertebrates living both on land and in water.

Q46. Elaborate on the primary characteristics of living beings using examples from plants and animals.

Nutrition & Growth: Living beings require food and water to grow in size (e.g., child growth, seed sprouting).
Respiration & Excretion: They exchange gases via breathing or stomata and excrete waste products like sweat or droplets.
Response to Stimuli: They react to environmental triggers (e.g., touch-me-not plant folding leaves, animals running from danger).
Reproduction: They produce young ones to preserve species continuity, eventually ending in death.