Science Olympiad Model Test Paper - 3 | Science Olympiad Class 8 PDF Download

Ans: (c)

• To determine that S is the mother of Q, we need to find the correct symbols that represent this relationship.
• In option (c) T@U%S#R©Q, the symbol % indicates that S is the husband of R, and the # indicates that S is the mother of Q.
• Thus, this option correctly shows that S is the mother of Q.
• The other options do not correctly represent S as the mother of Q based on the given symbols.

Ans: (a)

The triangles are given below:

agh, bhi, ijc, jdk, elk, fgl, bgj, aec, egj and bdf. So, there are total 10 triangles.

Ans: (b)

• The Venn diagram shows different categories of children.
• The circle is for boys, the triangle is for girls, and the square is for twins.
• To find the twin girl children, we look for the number inside the triangle that is also in the square.
• The number that represents the twin girl children is 4, which is indicated in the triangle and square intersection.

Ans: (c)People = diamond

dirty = triangle

hall = square

Number that is common for these 3 shapes is 6 which is represented by the red line.

Ans: (b)

• To find the answer, we need to look for symbols that have a number before them and a letter after them.
• In the sequence, the symbols that meet this condition are: #, ?, and $.
• Counting these, we find there are 3 such symbols.
• Thus, the correct answer is 3.

Ans: (b)

S = Start point, and E = End point

The person is 40 metres far from the starting point.

Ans: (d)

Hence, D is in the southwest with respect to the starting point A.

Ans: (a)

Ans: (c)

• The code involves a pattern where each letter in the word is shifted by a certain number of positions in the alphabet.
• For example, in PHILOSOPHY, each letter is transformed to create SFLJRQRNKW.
• Applying the same shifting pattern to PSYCHOLOGY results in SQBAKMOMJW.
• Thus, the correct encoded form of PSYCHOLOGY is SQBAKMOMJW.

Ans: (b)

• A and B are siblings.
• E is the wife of F.
• D is the son of E.
• If B is the daughter of F, it means B is the daughter of E also.

So, B is the sister of D.

Ans: (c)

• When the flask is placed in melting ice, the temperature of the air inside the flask drops.
• As the temperature decreases, the molecules move slower, which means the speed decreases.
• According to the gas laws, if the volume of the flask remains constant and the temperature decreases, the pressure inside the flask also decreases.
• Thus, the correct answer is that the pressure decreases and the speed decreases.

Ans: (b)
Veins carry de-oxygenated blood from all the body parts back to the heart and phloem transport food and xylem transports water and minerals from the soil.

Ans: (d)

• The temperature of a liquid drops during evaporation because the higher energy molecules leave the liquid.
• This process results in a decrease in average energy, as the remaining molecules have lower energy.
• The escape of these high-energy molecules into the air as vapor is what primarily causes the cooling effect.
• Thus, the correct explanation is that the average energy drops due to the loss of these energetic molecules.

Ans: (b)

• The full moon occurs when the Earth is positioned between the Sun and the Moon, which is represented as SEM.
• The new moon happens when the Moon is between the Earth and the Sun, shown as SME.
• Thus, the correct representation for the full moon is SEM and for the new moon is SME.
• Therefore, option (b) is the correct answer.

Ans: (d)
Trachea is the respiratory organ in cockroach. Prawn and crab respire through gills. Sponges and Hydra respire through their body surface (skin). Lungs are the respiratory organs in humans.

Ans: (c)

• Transpiration is the process where plants release water vapor through tiny openings called stomata.
• This process helps in cooling the plant and maintaining nutrient flow from roots to leaves.
• While photosynthesis and respiration are vital for energy production, they do not primarily focus on water release.
• Evaporation refers to the change of water from liquid to vapor, but it is not a process specific to plants.

Ans: (b)

• The correct answer is (b) Phosphorus, Chlorine, Sulfur, as all these elements are classified as non-metals.
• In contrast, option (a) includes Magnesium, which is a metal.
• Option (c) contains Calcium and Sodium, both of which are metals.
• Option (d) has Aluminum and Boron, where Aluminum is also a metal.

Ans: (c)
Spore formation is a method of asexual reproduction. Plants like ferns, moss, fungi reproduce by this method.

Ans: (b)
The reproduction in which only vegetative parts of a plant take part is known as vegetative propagation. The vegetative parts are stem, leaves and roots. Flowers are not involved in vegetative propagation.

Ans: (d)

There are advantages to being multicellular rather than unicellular. These include allowing the organism to be larger, and cell differentiation (having different types of cells with different functions). Cellular differentiation is the process by which a less specialised cell becomes a more specialised cell type. Differentiation occurs many times during the development of a multicellular organism as the organism changes from a single zygote to a complex system of tissues and cell types.

Ans: (a)

• The speed of light is affected by the medium it travels through.
• When light moves from air (a less dense medium) into water (a denser medium), it slows down.
• This change in speed is due to the optical density of water being higher than that of air.
• Thus, the correct answer is that the speed of light decreases when it enters water.

Ans: (d)

• Iron is a magnetic material, which means it can be attracted to a magnet.
• Other materials like wood, paper, and plastic do not have magnetic properties and will not be attracted.
• This property of iron is due to its atomic structure, which allows it to respond to magnetic fields.
• In everyday life, you can see this when magnets stick to refrigerators, which are often made of iron.

Ans: (c)

• Chemical change involves a transformation that alters the substance's chemical structure.
• In this case, burning of paper results in ash and smoke, indicating a new substance is formed.
• On the other hand, melting ice and dissolving sugar are physical changes where the original substances remain unchanged.
• Thus, the correct answer is the burning of paper, as it exemplifies a true chemical change.

Ans: (c)

• Fertilizers and pesticides are essential in agriculture as they provide the necessary nutrients that crops need to grow effectively.
• While they can enhance crop yield, they do not necessarily improve water retention or maintain soil fertility over long periods.
• It's important to use them wisely to avoid negative impacts on the environment.
• Thus, the correct statement is that they help in providing the required nutrients to crops for better growth.

Ans: (a)

• To find the speed of the object, we use the formula: speed = distance / time.
• The object travels a distance of 40 meters in 5 seconds.
• So, speed = 40 meters / 5 seconds = 8 m/s.
• This means the object moves 8 meters every second.

Ans: (d)

• The main component of biogas is methane, which is a type of gas produced during the breakdown of organic matter.
• Biogas is generated through anaerobic digestion, where microorganisms decompose organic materials in the absence of oxygen.
• While other gases like carbon dioxide are present, methane is the most significant because it is a valuable energy source.
• Understanding the composition of biogas is important for its use in renewable energy applications.

Ans: (c)

Ans: (c)

• The chemical name for baking soda is sodium bicarbonate.
• This compound is commonly used in baking as a leavening agent.
• It helps dough rise by producing carbon dioxide gas when it reacts with acids.
• Other options like sodium hydroxide and potassium bicarbonate are different compounds and not used as baking soda.

Ans: (b)

• Carbon dioxide is a major greenhouse gas that traps heat in the atmosphere, leading to the phenomenon known as global warming.
• While other gases like methane also contribute to warming, carbon dioxide is the most significant due to its large volume in the atmosphere.
• Understanding the role of carbon dioxide is crucial for addressing climate change and implementing effective environmental policies.
• Reducing emissions of carbon dioxide can help mitigate the effects of global warming.

Ans: (b)

• Pellagra is caused by a deficiency of Vitamin B3, which is essential for energy metabolism and skin health.
• Scurvy is linked to a lack of Vitamin C, not B1.
• Rickets is due to insufficient Vitamin D, not C.
• Beriberi results from a deficiency of Vitamin B1, not D.

Ans: (b)

• The flow chart categorizes substances based on their taste and pH level.
• Option (b) indicates that the first item is Sour, which aligns with the Acidic nature of Calamine.
• Other options do not correctly match the characteristics of the substances represented in the flow chart.
• Thus, the correct representation of I, II, and III is Sour, Acidic, Calamine.

Ans: (c)

• X represents the material used for paving, which is bitumen.
• Y is coal tar, a byproduct of coal that is used in road construction.
• Z is coal, which is the source material.
• coal, coal tar, bitumen, making option (c) the right answer.

Ans: (b)

• The China rose indicator is expected to turn green in acidic solutions, not blue.
• In test tubes 2 and 4, the indicator should show a green color if the solution is acidic.
• Other statements about turmeric, methyl orange, and phenolphthalein are correct based on their expected reactions with acids and bases.
• Thus, option (b) is the incorrect statement regarding the experimental setup.

Ans: (a)

• Producers are organisms that create their own food, primarily through the process of photosynthesis.
• In this case, grass is a plant that uses sunlight to produce energy, making it a primary producer.
• Other options like lion, rabbit, and eagle are consumers, as they rely on other organisms for food.
• Thus, the correct answer is grass, as it is the only producer listed.

Ans: (c)

• Coal is a fossil fuel and is not renewable, meaning it cannot be replenished in a short time frame.
• In contrast, wind, solar, and hydropower are all renewable sources, as they are naturally replenished.
• Using coal contributes to environmental issues, while the other options are cleaner alternatives.
• Understanding the difference between renewable and non-renewable sources is crucial for sustainable energy practices.

Ans: (a)

• Copper is widely recognized as the best conductor of electricity due to its high electrical conductivity.
• It allows electric current to flow through it with minimal resistance, making it ideal for electrical wiring.
• In contrast, materials like rubber, plastic, and glass are insulators, meaning they do not conduct electricity well.
• This property of copper is why it is commonly used in electrical applications.

Ans: (c)

• The process that causes rusting of iron is oxidation. This occurs when iron reacts with oxygen in the presence of moisture.
• During oxidation, iron loses electrons and forms iron oxide, which is commonly known as rust.
• This reaction is a type of corrosion that weakens the metal over time.
• Preventing rust involves reducing exposure to moisture and oxygen, such as through painting or galvanizing the iron.

Ans: (b)

• Carbon dioxide is a major greenhouse gas that traps heat in the atmosphere.
• It is released through activities like burning fossil fuels and deforestation.
• While other gases like methane also contribute to warming, carbon dioxide is the most prevalent.
• Reducing carbon dioxide emissions is crucial for combating climate change.

Ans: (d)

• The main component of biogas is methane, which is a type of gas produced during the breakdown of organic matter.
• Biogas is generated through anaerobic digestion, where microorganisms decompose organic materials in the absence of oxygen.
• While carbon dioxide and other gases are present, methane is the most significant because it is the primary fuel source.
• Understanding the composition of biogas is important for its use in energy production and waste management.

Ans: (b)

• The digestive system is primarily responsible for breaking down food, absorbing nutrients, and eliminating waste.
• Absorption, digestion, and ingestion are all key functions of this system.
• Respiration, however, is related to the process of breathing and gas exchange, not digestion.
• Thus, the correct answer is (b) Respiration, as it does not pertain to the digestive system's functions.

Ans: (c)

• The energy stored in food is known as Chemical energy. This is the energy that is released when food is metabolized by our bodies.
• Chemical energy is essential for all bodily functions, as it powers everything from movement to growth.
• Unlike kinetic energy, which is the energy of motion, or potential energy, which is stored energy based on position, chemical energy is specifically related to the bonds between atoms in food molecules.
• When we eat, our bodies convert this chemical energy into usable energy to fuel our activities.

Ans: (a)

• Acids are substances that can donate protons (H+) in a solution.
• One of the key properties of acids is that they turn blue litmus paper red, indicating their acidic nature.
• Unlike bases, acids typically have a sour taste and do not feel slippery.
• Additionally, acids usually have a pH less than 7, not greater.

Ans: (d)

Sex chromosomes of the father determine the sex of an unborn baby. The belief that the mother is responsible for the sex of her baby is completely wrong and to blame her for this is totally unjustified.

Ans: (c)

• The human circulatory system is designed to circulate blood throughout the body.
• In one complete cycle, blood flows through the heart twice, which is essential for oxygenation.
• Arteries carry oxygenated blood away from the heart, while veins return deoxygenated blood.
• The pulmonary artery is responsible for sending blood to the lungs, not the pulmonary vein.

Ans: (a)

1. The sulphurous acid turns blue litmus paper red. This statement is true.

2. In general, metallic oxides are acidic in nature. This statement is false as they are basic in nature.

3. Generally, non-metals do not react with water, although they may be very reactive in air. Such non-metals are stored in water. For example, phosphorus is a very reactive non-metal. It catches fire if exposed to air. To prevent the contact of phosphorus with atmospheric oxygen, it is stored in water.

Ans: (c)

The correct identification of cells A, B and C is:

A - Red blood cells

B - Nerve cells

C - Smooth muscle cells

Nerve cells contain a nucleus present in the cyton of the nerve cell. RBCs lack a nucleus.

Ans: (b)
Switch off the flame of the burner. Put a lid on the frying pan to cut off contact between fuel and oxygen and the flame will go off.

Ans: (a)

Pictures A and B come under the category of bacteria.

Ans: (c)

• Q is photosynthetic, meaning it can produce its own food using sunlight, while S is parasitic, which means it relies on another organism for nourishment.
• This distinction is important in understanding the roles these organisms play in their ecosystems.
• Options (a), (b), and (d) do not accurately describe the relationships or characteristics of the organisms P, Q, R, and S.
• Thus, option (c) is the correct statement regarding these organisms.

Ans: (a)

• A luminous flame is a bright yellow flame that gives off light. It undergoes incomplete combustion as it does not get the oxygen that it requires.
• A non-luminous flame is colorless and is much hotter. It undergoes complete combustion as it draws much more oxygen and gets much hotter.