Science Olympiad Previous Year Questions - 2 | Science Olympiad Class 4 PDF Download

Ans: (c)

• The letters O, K, H, E, C, Y can be rearranged to form the word "CHOKEY".
• By selecting the combination 3, 1, 5, 2, 4, 6, we get the order: C, H, O, K, E, Y.
• This arrangement results in a valid English word, which is the goal of the question.
• Other combinations do not yield a meaningful word.

Ans: (d)

• Sonali is the person who is positioned to the North-West of Sakshi.
• Understanding directions is key; North-West is a specific location relative to Sakshi.
• By visualizing a map, you can see where each person is located in relation to Sakshi.
• In this case, Sonali is the correct answer as she fits the criteria given in the question.

Ans: (c)

• The question involves a series of name changes among fruits.
• Here, Mango is called Apple, which means when we refer to Apple, we actually mean Mango.
• However, the term king of fruits traditionally refers to Mango.
• Since Mango is now called Apple, the answer to the question is Apple.

Ans: (b)
Arnav is facing towards, north i.e., Arnav is facing towards restaurant. After making 34turn to his right and.12 turn in clockwise direction he will face towards mountains. Now, if he want to face towards bookstore he will have to make 58 turn clockwise.

Ans: (b)

Ans: (c)

• Mangrove plants are unique because they thrive in coastal areas where the soil is often waterlogged.
• Their roots grow above the ground to access oxygen, which is limited in the saturated soil.
• When the soil is too wet, it lacks sufficient air for the roots, making it hard for the plants to breathe.
• By growing their roots above the soil, mangroves can take in the necessary air to survive and grow.

Ans: (d)

• The Venn diagram shows the characteristics of different plants.
• Hydrilla and Wolffia share certain features that are highlighted in the diagram.
• Water hyacinth does not fit the criteria for plant X.
• Thus, the correct identification for plant X is both Hydrilla and Wolffia.

Ans: (b)

• The naphthalene balls are in a solid state initially.
• Over time, they sublime, which means they change directly from a solid to a gas without becoming a liquid first.
• This process is called sublimation, and it is common for certain substances like naphthalene.
• Thus, the correct answer is Solid → Gas.

Ans: (C) 

• Potassium is commonly found in bananas, which corresponds to (iii).
• Vitamin A is typically found in fish oil, corresponding to (i).
• Iron is often associated with jaggery, which aligns with (iv).
• Vitamin C is abundant in oranges, matching with (ii).

Ans: (a)

• Freezing is the best method to keep raw meat fresh for an extended period. It slows down the growth of bacteria and prevents spoilage.
• Frying, boiling, and roasting are cooking methods that do not preserve meat; they actually cook it, which reduces its shelf life.
• By freezing meat, you can store it for months without losing its quality.
• This method is widely used in households and food industries to ensure meat remains safe to eat over time.

Ans: (a)

• The question asks to strike out every alternate letter starting from the first letter.
• If we apply this to option (a) FCKOUTATBOLN, we get the letters F, K, T, A, B, L, N, which can be rearranged to form the word "FIBER".
• This indicates that the correct answer is indeed option (a), as it leads to a name associated with a fiber made from chemicals.
• The other options do not yield a recognizable fiber name when applying the same method.

Ans: (b)

• Axis is the correct answer as it refers to the imaginary line that connects the North and South Poles.
• This line is tilted at approximately 23.5 degrees, which is significant for understanding the seasons on Earth.
• The Equator is a different concept, as it is the line that divides the Earth into the Northern and Southern Hemispheres.
• Understanding the Axis helps in grasping how the Earth rotates and how this affects climate and daylight.

Ans: (c)

• The correct method to separate a mixture of sand and water is through filtration. This process uses a filter to allow the liquid (water) to pass through while trapping the solid (sand).
• Magnet is used for separating magnetic materials, which is not applicable here.
• Winnowing is a technique used to separate grains from chaff, not suitable for sand and water.
• Threshing is related to separating grains from plants, which does not apply to this mixture.

Ans: (A)

• Statement (i): A Spruce tree indeed has needle-shaped leaves, which makes this statement true.
• Statement (ii): An Elm tree is not an evergreen plant; it is a deciduous tree, so this statement is false.
• Statement (iii): In a cactus, the stem stores water, which is true as cacti are adapted to dry environments.
• Thus, the correct identification is T F T, corresponding to option (a).

Ans: (b)
Condensation and Freezing release heat.

Ans: (c)

• The bottle cap functions as a screw because it has a spiral thread that allows it to be twisted onto the bottle.
• This design helps create a tight seal, preventing liquids from spilling.
• While it may seem like a simple object, the screw mechanism is essential for its functionality.
• Other options like inclined plane or wheel and axle do not accurately describe how a bottle cap operates.

Ans: (b)

• The oil gland, also known as the uropygial gland, is located at the base of a bird's tail.
• This gland produces oil that birds use to preen their feathers, keeping them waterproof and in good condition.
• Other options like spur, fur, and spiracle do not relate to the tail area of birds.
• Thus, the correct answer is the oil gland, which plays a crucial role in feather maintenance.

Ans: (c)

• Statement I indicates that X is a planet with a long orbital period, which is characteristic of Jupiter.
• Statement II describes Y, which is likely Uranus, known for its unique rotation and long orbital period.
• Statement III identifies Z as the brightest planet, which is Venus.
• Among the options, Y has 27 Moons is correct, as Uranus indeed has 27 known moons.

Ans: (a)

• Seasonal Differences: In December, it is summer in Australia, while it is winter in India. This means that Akshita is likely to be experiencing warm weather.
• Swimming: Given the warm climate, swimming in a cold water pool is a common activity during this time in Australia.
• Other Options: Sitting near a bonfire and wearing woollen gloves are activities associated with cold weather, which would not be applicable in Australia during December.
• Conclusion: Therefore, the most probable activity for Akshita is swimming in a cold water pool.

Ans: (d)

• The peepal leaf is heart-shaped with a pointed tip. It has a distinctive prominent central vein and symmetrical sides.
• Neem leaves are more elongated and have a different texture.
• Banana leaves are large and broad, unlike the Maple's shape.

• Mangoes are typically oval or kidney-shaped, with a slightly curved or rounded appearance.

Ans: (a)

• Saturn is famous for its stunning rings, which are made of ice and rock particles.
• Other planets like Mars and Venus do not have rings.
• While some other gas giants like Jupiter and Uranus also have rings, the question specifically asks about the options provided.
• Thus, the correct answer is Saturn, as it is the only planet listed that is well-known for its rings.

Ans: (c)

• Leaves are the primary sites for photosynthesis in plants. They contain tiny openings called stomata that allow carbon dioxide to enter from the air.
• The process of photosynthesis uses sunlight, water, and carbon dioxide to produce glucose and oxygen.
• While roots absorb water and nutrients, and stems support the plant, it is the leaves that are crucial for taking in carbon dioxide.
• Thus, the correct answer is the leaf, as it plays a vital role in the plant's ability to produce food.

Ans: (d)

• Plasmodium is a well-known parasite that causes malaria in humans.
• Unlike Amoeba, Leech, and Earthworm, which can be free-living or have different roles in the ecosystem, Plasmodium specifically relies on a host for survival.
• It lives and reproduces inside the host's body, making it a true parasite.
• Understanding the difference between parasites and other organisms is crucial in biology.

Ans: (b)

• To determine if items will sink in water, we need to consider their density compared to water.
• In option (b), both the coin and the paper clip are made of metal, which is denser than water, causing them to sink.
• In contrast, items like a feather or a balloon are less dense and will float.
• Thus, the correct answer is (b) Coin, Paper clip, as both will sink in water.

Ans: (d)

• Understanding the solar system: The solar system consists of the Sun and all celestial bodies that are bound to it by gravity, including planets, moons, asteroids, and comets.
• Identifying the options: An asteroid, a satellite (moon), and a meteor are all part of the solar system.
• Defining a galaxy: A galaxy is a massive system that contains billions of stars, along with gas and dust, and is not part of our solar system.
• Conclusion: Therefore, the correct answer is (d) A galaxy, as it is not a member of the solar system.

Ans: (d)

• Plague is caused by bacteria and is primarily transmitted through fleas that infest rodents, not mosquitoes.
• In contrast, Malaria, Chikungunya, and Dengue are all viral diseases that are indeed spread by mosquito bites.
• Understanding the transmission methods of these diseases is crucial for prevention and control.
• Thus, the correct answer is (d) Plague, as it is not transmitted by mosquitoes.

Ans: (c)

• The main role of white blood cells is to combat infection. They are a crucial part of the immune system.
• Unlike red blood cells, which carry oxygen, white blood cells are specifically designed to identify and destroy pathogens like bacteria and viruses.
• They also help in healing by removing dead cells and facilitating recovery from illness.
• In summary, their primary purpose is to ensure the body remains healthy by fighting off infections.

Ans: (a)

• Asteroids are primarily found in the asteroid belt, which is situated between the orbits of Mars and Jupiter.
• They are not classified as planets, but rather as small rocky bodies.
• The Earth's moon is not an asteroid; it is a natural satellite.
• Therefore, the only correct statement is that they are found between the orbits of Mars and Jupiter.

Ans: (c)

• Vitamin D is often called the sunshine vitamin because our bodies produce it when exposed to sunlight.
• This vitamin is essential for maintaining healthy bones and teeth, as it helps the body absorb calcium.
• While other vitamins like A, B12, and C are important, they do not have the same relationship with sunlight as Vitamin D does.
• Therefore, the correct answer is Vitamin D, which is crucial for overall health.

Ans: (c)

• The process of a candle burning involves both physical and chemical changes. When the candle is lit, the wax melts, which is a physical change.
• At the same time, the wax reacts with oxygen in the air to produce heat, light, carbon dioxide, and water vapor, which is a chemical change.
• Thus, the burning of a candle is a great example of how two types of changes can occur simultaneously.
• In summary, the correct answer is (c) because it encompasses both the melting of wax and the combustion process.

Ans: (a)
The categories are Jal, Agni, Vayu, Akash and Prithvi.

Ans: (b) 

• The question involves three types of soil samples: W, X, and Y, each weighing 100 g.
• After adding 100 mL of water, the samples were weighed again to see how much water they retained.
• The soil that retains the right amount of moisture without becoming too wet is often the best for making idols.
• In this case, soil sample W is determined to be the most suitable for idol making based on its properties after wetting.

Ans: (d)

• The order of distance between molecules indicates that P has the largest distance, followed by Q, and then R with the smallest distance.
• In solids, molecules are closely packed, so they have the least distance. In liquids, they are further apart, and in gases, they are much more spread out.
• Thus, P must be Gas, Q must be Liquid, and R must be Solid.
• Therefore, the correct order is Gas, Liquid, Solid, which corresponds to option (d).

Ans: (d)
Freezing converts liquids into solids.

Ans: (d)

• The curved surface of the Earth causes the ship to disappear from the bottom up as it moves further away.
• This phenomenon occurs because the Earth is not flat; it is round, so as the ship sails away, it goes beyond the horizon.
• The horizon is the line where the earth's surface and the sky appear to meet, and due to the curvature, objects can become hidden from view.
• Thus, the shape of the Earth is the reason we can no longer see the ship as it moves farther from the shore.