Solutions-NCERT-Class-6-Science-Curiosity-Chapter-6-Materials Around Us-CBSE

• A tumbler must be made of a material that is capable of holding water.
• Since cloth has pores and is not waterproof, it cannot hold water; the liquid would simply leak through it.

No, it would not be a good idea.

• We choose materials based on their properties and the purpose for which the object is used.
• Cooking utensils must withstand high heat, whereas paper-like materials would catch fire and burn.

No.

• While lustrous (shiny) materials are usually metals—such as iron, copper, zinc, aluminium, and gold—not all things that shine are metals.
• The surfaces of some non-metallic materials can be made to look shiny by polishing or coating them with thin layers of plastic or wax.

Yes, water is a transparent material because objects can be seen clearly through it.

• It can be made opaque (or translucent) by mixing in insoluble materials, such as mud or chalk powder, which prevent light from passing through clearly.

No.

• Only materials that are soluble in water, like sugar or salt, will disappear.
• Materials that are insoluble, such as sand, sawdust, or chalk powder, will not disappear even after being stirred for a long time.

• It varies. Some liquids mix completely with water, while others do not.
• Generally, vinegar and honey are soluble and will mix with water, but oil is insoluble and will form a separate layer when left undisturbed.

• Some gases are soluble in water, while others are not.
• For example, oxygen gas dissolves in water, which is critical for the survival of plants and animals living in aquatic environments.

Yes. Every material possesses the properties of mass and volume.

Yes, air is matter. This is because it occupies space (volume) and has mass, which are the two defining characteristics of matter.

Students should do it by self as a fun and learn activity.

• The primary reason for using transparent containers is that they allow people to see through them clearly.
• Shopkeepers and homeowners can easily identify the contents of the container without having to open it.

• It saves time when looking for a specific item, as the objects inside are clearly visible through the material.
• It allows one to easily see how much of a material is left so they know when it needs to be refilled or restocked.

(i) Wood is translucent while glass is opaque. [False]

Correction: Wood is opaque because you cannot see through it at all, while glass is transparent because objects can be seen clearly through it.

(ii) Aluminium foil has lustre while an eraser does not. [True]

(iii) Sugar dissolves in water whereas sawdust does not. [True]

(iv) An apple is a matter because it occupies no space and has mass. [False]

Correction: An apple is matter because it occupies space (has volume) and has mass. The defining characteristics of matter are that it must possess both mass and volume.

(i) Iron, cement, and stones.

(ii) Plastic and bamboo.

(iii) Wood, bamboo, and plastic.

(iv) Plastic and iron.

Choice of Materials for Waste Containers :

(i) Food Waste: Use plastic or coated metal because they do not absorb water and are easy to clean

• Properties to Consider : Water Resistance

(ii) Broken Glass: Use thick plastic or iron because they are strong and do not break easily (Hardness).

• Properties to Consider : Hardness

(iii) Wastepaper: Use plastic, bamboo, or cardboard because they are light and suitable for dry waste.

• Properties to Consider : Light Weight:

Other Properties to Consider :

• Easy to Clean: Food waste containers should be washable to maintain hygiene.
• Opacity: Opaque containers hide the waste inside and look neat.

(i) transparent, opaque

(i) Analysis of Material X :

• Material X is hard and soluble.
• Possible Examples: Common salt, sugar, or glucose.

Justification:

• Because it is rigid and does not change its shape easily when pressed, it fits the definition of a hard material.
• Since it disappears completely when mixed with water, it is classified as soluble.

(ii) Analysis of Material Y

• Material Y is soft and insoluble.
• Possible Examples: An eraser, a sponge, or wax.

Justification:

• Because it easily changes its shape when pressed, it fits the definition of a soft material.
• Since it remains unchanged and does not disappear when mixed with water, it is classified as insoluble.

(a) I have lustre. : Metal, like iron, copper, aluminium, and gold.

(b) I can be easily compressed : A soft material, such as an eraser or sponge.

(c) I am hard and soluble in water : Sugar or Salt.

(d) You cannot see clearly through me : A translucent material, such as butter paper or frosted glass.

(e) I have mass and volume but you cannot see me : Air. Air is classified as matter because it occupies space (volume) and has mass, even though it is transparent and typically invisible.

• "I am opaque and you cannot see through me at all. I am used to make doors and furniture. Who am I?" (Answer: Wood).
• "I am transparent and essential for all living things. Many materials like sugar and salt disappear when they are put into me. Who am I?" (Answer: Water).
• "I am hard and opaque, but if I am left in the rain, I might lose my lustre and look dull. Who am I?" (Answer: Iron or Metal).

Soluble pairs :

• Vinegar and water
• Glucose and water

Insoluble pairs :

• Mustard oil and water
• Wheat flour and water