Science Olympiad Previous Year Paper - 3 | Science Olympiad Class 6 PDF Download

Ans: (c)

This is an alternating subtraction series in which 2 is subtracted twice, then 3 is subtracted once, then 2 is subtracted twice, and so on.

Ans: (b)

• In the sequence, we need to find the 5's that are immediately preceded by 4 and not followed by 9.
• The valid occurrences are: [4 5] 5, [4 5] 6, and [4 5] 2.
• Counting these, we find there are 3 such occurrences.
• Thus, the answer is 3.

Ans: (c)

If Wednesday is on 10^th, then Sunday is on 14^th. So, it means that the anniversary is on 14^th.  

Ans: (b)

Grandfather's son means either son or uncle.

Mother of uncle or son is grandmother.

Ans: (c)
Each time, we are multiplying by 2 and then adding 2. 43 x 2 = 86 + 2 = 88 88 x 2 = 176 = 176 + 2 = 178 (actual) 178 x 2 = 356 + 2 = 358 So, 179 is the odd one out..  

Ans: (b)

• The series starts with the numbers 8, 14, 26, and we need to find the missing number.
• The **difference** between the numbers is increasing: 14 - 8 = 6, 26 - 14 = 12.
• The next difference should be 18 (which is 6, 12, and then 18), so 26 + 18 = 44.
• The final differences confirm the pattern, leading to the missing number being **44**.

Ans: (b)

• The letters taken from EXPLORATION are **E**, **L**, **A**, and **N**.
• These letters can form meaningful words such as **LEAN** and **LANE**.
• Since multiple words can be created, the answer is **Y**.
• Thus, the correct response is **Y** indicating that more than one word can be formed.

Ans: (c)
The pattern followed is: + 4, + 4 + 4.

B + 4 = F, F + 4 = J = BFJ

C + 4 = G, G + 4 = K = CGK

D + 4 = H, H + 4 = L = DHL

Similarly,

E + 4 = I, I + 4 = M = EIM

Ans: (b)

• The letters of the word **BUILDER** are arranged in **alphabetical order**.
• When we sort the letters, we get **BDEILRU**.
• This means that the code for BUILDER in this language is **BDEILRU**.
• Thus, the correct answer is option (b).

Ans: (b)

The pattern followed is: + 3, + 3, + 3.

So, LIGHT = L + 3 = O, I + 3 = L, G + 3 = J, H + 3 = K, T + 3 = W

hence, OLJKW

So, SOUND = S + 3 = V, O + 3 = R, U + 3 = X, N + 3 = Q, D + 3 = G

Hence, VRXQG

Ans: (a)

If a magnet is left to itself over a long period of time, it gets demagnetised, i.e. it loses its magnetic property.  

Ans: (c)

Glass sheet is a transparent object, not an opaque object.

An opaque object is an object through which light cannot pass. The light is either reflected, scattered, or absorbed.

Ans: (b)

Deficiency of proteins in the diet for a long time results in swelling of the face, swollen neck, undergrowth of the body, etc. This is because proteins are the building blocks of the body and should be taken in sufficient amounts.  

Ans: (b)
Magnesium hydroxide reduces stomach acid and increases water in the intestines which may induce defecation. Magnesium hydroxide is used as a laxative to relieve occasional constipation (irregularity) and as an antacid to relieve indigestion, sour stomach, and heartburn.  

Ans: (a)

• A fixed pulley alters the direction of the force applied, which allows you to pull down instead of lifting up.
• This change in direction makes it feel easier to lift the object, as you can use your body weight to assist.
• While the amount of work done remains the same, the way you apply your force is more efficient.
• Thus, the correct explanation is that the direction of the force is changed, making the task seem easier.

Ans: (c)

• The object will appear black because the blue plastic only allows blue light to pass through.
• Since the object reflects green light under white light, the blue plastic blocks this green light.
• As a result, the object does not reflect any light, making it appear black.
• This demonstrates how color perception changes based on the light that is filtered through different materials.

Ans: (b)

• The process starts with **chemical energy** from the muscles when you lift the hammer.
• This **chemical energy** is converted into **kinetic energy** as you swing the hammer down.
• Upon impact, the kinetic energy is transformed into **sound energy** (the noise of the hammer hitting the nail) and **heat energy** (due to friction).
• Thus, the correct order of energy conversion is: **Chemical energy → kinetic energy → (sound energy + heat energy)**.

Ans: (c)

• Jupiter's seasons are very different from Earth's because it has a slight axial tilt.
• Statement 1 is true: Jupiter does not have short seasons like Earth.
• Statement 2 is false: Jupiter is not more tilted than Earth; it is actually less tilted.
• Thus, the correct answer is that statement 1 is true while statement 2 is false.

Ans: (b)

• The **hour hand** moves **30°** for each hour.
• From **noon** to **5:20 PM**, there are **5 hours and 20 minutes**.
• In **5 hours**, the hour hand turns **150°** (5 x 30°).
• In **20 minutes**, the hour hand moves an additional **10°** (1/3 of 30°).
• So, the total angle turned is **150° + 10° = 160°**.

Ans: (c)

• Magnetic force can actually do both: it can pull and push depending on the interaction of the poles.
• When two magnets are close, if opposite poles meet, they attract (pull), and if like poles meet, they repel (push).
• Thus, saying that magnetic force is only a pulling force is incorrect.
• The other statements about increasing strokes or coils and losing magnetism when heated are true.

Ans: (b)

• Sedimentation is a process that allows heavier and insoluble particles to settle at the bottom of a liquid, effectively separating them from lighter components.
• Filtration is used to separate solids from liquids, while distillation separates liquids based on boiling points.
• Chromatography separates substances based on their movement through a medium.
• Thus, sedimentation is specifically effective for separating based on weight and solubility.

Ans: (a)

An aqueous solution turns blue litmus solution red, it means the given solution is acidic in nature. Since sodium hydroxide is basic in nature, the excess addition of sodium hydroxide would change the nature of the solution to basic. Therefore, the basic solution turns red litmus solution to blue again.  

Ans: (b)

• Metals are known for being good conductors of electricity and heat.
• They also have a lustrous appearance, meaning they shine when polished.
• Most metals are solid at room temperature and are typically opaque, meaning you cannot see through them.
• Therefore, the correct combination of characteristics that metals exhibit is (i), (iii), (iv), and (v).

Ans: (b)

In plants, photosynthesis takes place in chloroplasts, which contain the chlorophyll. Chloroplasts are surrounded by a double membrane and contain a third inner membrane, called the thylakoid membrane, that forms long folds within the organelle.  

Ans: (c)

• At -5°C, substance X is in a liquid state. In this state, particles do not maintain a definite shape but do have a definite volume.
• At -20°C, the particles experience maximum interparticle forces, indicating they are more tightly packed.
• At 105°C, the particles are further apart, leading to maximum interparticle distance.
• At 120°C, the particles are in a gaseous state, lacking both definite shape and volume.

Ans: (c)

• The water droplets on the glass are due to the process of condensation.
• As the glass is cold, the water vapour present in the air cools down and turns into liquid.
• This happens because the air around the glass is warmer than the glass itself.
• Thus, the water droplets form on the outer surface of the glass from the moisture in the air.

Ans: (c)
Carbon dioxide passed into limewater gives a milky solution. This is due to the insoluble suspension of calcium carbonate formed. Ca(OH)₂(aq) + CO₂(g) → CaCO₃(s) + H₂O(l)  

Ans: (a)

Citric acid is responsible for the sour taste of orange juice.  

Ans: (c)

• Statement 1 is true because the cotton plant thrives in black soil and a warm climate.
• Statement 2 is false; cotton fibres are actually separated from the seeds through a process called ginning, not spinning.
• Thus, while the first statement is correct, the second one is incorrect.
• Therefore, the correct option is that Statement 1 is correct but Statement 2 is incorrect.

Ans: (a)
In olden days, shadows caused by objects placed in the sun were used to measure time. Such a device is called a sundial or Samrat Yantra.  

Ans: (d)
Chlorofluorocarbons (CFCs) and other halogenated ozone depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion.  

Ans: (c)

• The small white structures that Reena observed are called **radicles**.
• These **radicles** are the initial stage of root development in plants.
• As the seeds germinate, these structures will grow into **roots**, anchoring the plant and absorbing water and nutrients.
• Thus, the correct answer is **roots**.

Ans: (b)

• Hemp fibres are actually derived from the stem of the plant, not the leaves, making statement (i) incorrect.
• Statements (ii), (iii), and (iv) are accurate: bast fibres include jute, hemp, and sisal; silk cotton comes from the kapok tree; and burning wool does smell like burning hair.
• Thus, the correct combination of statements is (ii), (iii), and (iv).

Ans: (d)

• Stamens are known as the male reproductive parts of a plant, which play a crucial role in reproduction.
• In the context of plants, the petiole is the short stalk that connects the leaf to the stem, allowing for support and nutrient transport.
• The other options do not correctly match the statements provided, making option (d) the right choice.

Ans: (b)
The food chain follows the order as given below: Producer -> Primary consumer -> Secondary consumer -> Tertiary consumer
Hence, Grass -> Grasshopper -> Frog -> Snake
Frog = Secondary consumer

Ans: (d)

• Air is a mixture that includes dust particles and water vapour, making option (a) true.
• Air does not have a fixed shape or volume, which supports option (b) as correct.
• Air has mass and takes up space, confirming option (c) is accurate.
• However, option (d) is incorrect because air is compressible, meaning it can be squeezed into smaller volumes.

Ans: (a)

• Salmon actually migrate from the sea to freshwater to breed, not the other way around.
• The Arctic tern is known for having the longest migration route among animals.
• Migration refers to the seasonal mass movement of animals from one location to another.
• Chameleons are famous for their ability to change skin color to adapt to their surroundings.

Ans: (b)

• Dahlia is a plant that primarily reproduces through tuberous roots, not by stems.
• In contrast, ferns reproduce using spores, Bryophyllum uses leaves for propagation, and sweet potato is known for its root structure.
• Thus, the match for Dahlia is incorrect as it is associated with stems instead of roots.

Ans: (c)

Earthworm has bristles on the underside of the body to support movement. The bristles are connected with muscles. The bristles help to get a good grip on the ground. 

Ans: (d)

Higher speed is indicated by the following statements:

(i) Given distance has been covered in a shorter time.

(iii) Larger distance is covered in a given time.

Ans: (c)

 The cornea is responsible for focusing light, but it does not form an image. Instead, the retina is where the image of an object is actually formed. The other parts are correctly matched with their functions.

Ans: (b)

• Obsidian is a type of rock that is formed from volcanic activity.
• It is created when lava cools quickly, resulting in a glassy texture.
• This rapid cooling prevents the formation of crystals, giving it a smooth appearance.
• Because of its glass-like quality, it is often called natural glass.

Ans: (b)

• Rubber is the material formed from the letters.
• It is commonly used in making truck tyres, erasers, and hose pipes.
• However, incandescent light bulbs are not made from rubber.
• Thus, the correct answer is (b) because rubber is not suitable for light bulbs.

Ans: (a)
Proteins are called the body-building foods as they help muscles to grow. Carbohydrates are called energy-giving foods as they provide essential energy to the body to work. Vitamins do not provide any energy to the body, but help in keeping the body healthy. 

Ans: (a)

Steps involved in the process of recycling paper:

• Paper is torn into small pieces.
• Soak these pieces in water for a day.
• Make a thick paste and spread it on a net or sieve.
• Let water drain off completely.
• Use an old cloth or newspaper to remove the extra water from the paste and dry it.
• Use this paste to get beautiful patterns.

Ans: (a)

Sorting is the process of separating hair of different textures during the processing of wool.

It is done after scouring.

Ans: (d)
Sublimation is a reversible change. When a substance sublimes on heating, it changes directly from the solid to gaseous state without passing through the liquid state. Desublimation, or deposition, is the reverse of this process in which a gas is directly converted into solid state on cooling.

Therefore, sublimation is a reversible change that can be undone or reversed.

Ans: (b)

Reflection on a plane mirror is an example of a regular reflection.

Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves.