CBSE Class 6 Science — NCERT Solutions

Given: Two types of seeds — Wheat and Kidney beans.

Concept used: The type of seed (monocot/dicot) determines the type of root system and leaf venation.

Analysis:

Wheat is a monocot seed (single cotyledon).

• Root type: Fibrous roots — a bunch of similar-sized thin roots arising from the base of the stem.
• Leaf venation: Parallel venation — veins run parallel to each other.

Kidney beans is a dicot seed (two cotyledons).

• Root type: Taproot system — one main root (taproot) with small side roots arising from it.
• Leaf venation: Reticulate venation — a net-like pattern of veins on both sides of a thick middle vein.

Summary Table:

Conclusion: Wheat (monocot) has fibrous roots and parallel venation, whereas Kidney beans (dicot) has taproot system and reticulate venation.

Given: Animals — Horse, Dolphin, Frog, Sheep, Crocodile, Squirrel, Whale, Earthworm, Pigeon, Tortoise.

Concept used: Animals are grouped as aquatic (live in water), terrestrial (live on land), or amphibious (live in both water and land) based on their habitat.

Grouping:

A — Aquatic animals (live primarily in water):

• Dolphin
• Whale

B — Terrestrial animals (live primarily on land):

• Horse
• Sheep
• Squirrel
• Earthworm
• Pigeon

C — Animals living in both habitats (water and land):

• Frog
• Crocodile
• Tortoise

Note: Frog, Crocodile, and Tortoise can live both in water and on land, so they are placed in section C.

Given: Jowar, Bajra, Ragi, Chana

Concept: Millets are a group of small-seeded cereal crops (nutri-cereals), while legumes/pulses are a different category of food crops.

Answer: The odd one out is Chana (Chickpea).

Reason: Jowar, Bajra, and Ragi are all millets (nutri-cereals/cereal crops). Chana is a legume (pulse), not a millet. It belongs to a completely different category of food crops.

Given: Kidney beans, Green gram, Soya bean, Rice

Concept: Legumes/pulses are protein-rich crops belonging to the family Fabaceae, while rice is a cereal crop.

Answer: The odd one out is Rice.

Reason: Kidney beans, Green gram, and Soya bean are all legumes (pulses) and are rich sources of protein. Rice is a cereal crop and is primarily a source of carbohydrates, not a legume.

(i) Given/Concept: When two magnets are brought close, unlike poles attract and like poles repel.
Answer: Unlike poles of two magnets attract each other, whereas like poles repel each other.

(ii) Given/Concept: Materials classified on the basis of their behaviour near a magnet.
Answer: The materials that are attracted towards a magnet are called magnetic materials.

(iii) Given/Concept: A freely suspended magnet always aligns along a fixed geographical direction.
Answer: The needle of a magnetic compass rests along the north-south direction.

(iv) Given/Concept: Poles of a magnet always exist in pairs; a single pole cannot exist.
Answer: A magnet always has two (North and South) poles.

(i) Statement: A magnet can be broken into pieces to obtain a single pole.
Answer: False (F)
Reason: When a magnet is broken into pieces, each piece has both a North pole and a South pole. A single pole (monopole) cannot be obtained.

(ii) Statement: Similar poles of a magnet repel each other.
Answer: True (T)
Reason: Like poles (N–N or S–S) always repel each other.

(iii) Statement: Iron filings mostly stick in the middle of a bar magnet when it is brought near them.
Answer: False (F)
Reason: Iron filings mostly stick near the ends (poles) of a bar magnet, where the magnetic force is strongest. Very few filings stick in the middle.

(iv) Statement: A freely suspended bar magnet always aligns with the north-south direction.
Answer: True (T)
Reason: Due to the Earth's magnetic field, a freely suspended bar magnet always comes to rest along the geographic north-south direction.

Given/Context: Some measuring devices (like measuring tapes) are made of flexible materials such as cloth or plastic.

Explanation:
Flexible measuring devices are used because not all objects have straight or flat surfaces. For example:

• The curved surface of a bottle or a ball cannot be measured with a rigid ruler.
• The length of a curved road or a body part (like the waist or chest) requires a flexible tape.

Conclusion: Some length measuring devices are made of flexible materials so that they can bend and conform to curved or irregular surfaces, allowing accurate measurement of lengths that cannot be measured with a rigid scale.

Given: Observation of kitchen organisation of edibles.

Sample Answer (students may write their own observations):

In my kitchen, edibles are usually kept together without a fixed system — spices, grains, pulses, and snacks may all be on the same shelf.

A better sorting method could be:

• Group 1 – Grains and Pulses: Rice, wheat, dal, etc. (stored in large airtight containers)
• Group 2 – Spices and Condiments: Salt, turmeric, chilli powder, etc. (stored in small labelled jars)
• Group 3 – Liquids: Oil, vinegar, sauces (stored in bottles on a separate shelf)
• Group 4 – Snacks and Ready-to-eat items: Biscuits, namkeen, etc. (stored in sealed packets or boxes)
• Group 5 – Perishables: Vegetables, fruits, dairy (stored in the refrigerator)

This classification is based on the type of material, size, and storage requirement, making it easier to find items quickly and keep the kitchen organised.

Correct option: (ii) 37.0 °C

The normal body temperature of a healthy human adult is taken to be 37.0 °C (which is equal to 98.6 °F on the Fahrenheit scale). 98.6 °C would be dangerously high, and 32.0 °C or 27.0 °C are far below normal body temperature.

Given: An ice cube is left in a cup at room temperature.

Observation: The ice cube gradually melts and turns into water (liquid).

Conclusion: Ice and water are the same substance. Ice is the solid state of water, and when heat from the surroundings is absorbed by the ice, it melts and becomes liquid water. Both ice and water are made of the same substance — they are simply two different states of water.

• Water flows but ice does not.
• Water splashes but ice does not.

These differences in behaviour are due to the different states (solid and liquid) of the same substance.

Correct Option: (ii) Sorting

Handpicking is used to manually sort and pick out unwanted or desired components from a mixture based on differences in size, colour, and shape. For example, removing small stones from pulses by hand is a form of sorting. It does not involve any liquid separation (filtration/decantation) or heating (evaporation).

Given: A figure (Fig. 11.9) showing various natural resources with jumbled names.

Note: Since the actual figure and jumbled names cannot be seen from the OCR, the common natural resources shown in such exercises are listed below with their classification.

Concept used: Resources that are replenished by natural processes within a reasonable time are renewable. Resources present in limited quantities that cannot be replenished within a reasonable time are non-renewable.

We match each item in Column I with the correct item in Column II using our knowledge of the Solar System:

• (i) Satellite of Earth → (d) Moon

The Moon is the natural satellite that revolves around the Earth.

• (ii) Red planet → (c) Mars

Mars appears reddish due to iron oxide (rust) on its surface, so it is called the Red Planet.

• (iii) Constellation → (a) Orion

Orion is a well-known constellation — a group of stars forming a recognisable pattern in the sky.

• (iv) Planet which is commonly called an evening star → (b) Venus

Venus is very bright and is often visible near the western horizon after sunset, so it is called the Evening Star (it is also called the Morning Star when visible before sunrise).

Final Matching:
(i) → (d), (ii) → (c), (iii) → (a), (iv) → (b)