Sorting Materials And Groups

Among the given options, soft drink contains carbonic acid.

i. The acid reacts with an iron nail and as a result, it loses its shine and appears dull.

ii. On the other hand, iron does not react with mustard oil, coconut oil, and kerosene. Hence, it does not lose its shine when kept in such liquids.

Completely soluble means when we pour some substances into the water, they completely disappear in water. We cannot see their particles.

In the given options, glucose is completely soluble in water.

i. The particles of glucose are so small; hence it becomes soluble in water.

ii. On the other hand, chalk powder, tea leaves and saw dust are insoluble in water.

iii. We can see their particles in water which settles down at the bottom.

Transparent: Those substances or materials, through which things can be seen, are called transparent.

Among the given options, magnifying glass and glass tumbler are the materials through which things can be seen.

Hence, they both are transparent.

Opaque: Those substances or materials, through which things cannot be seen, are called opaque.

Among the given options, mirror and magnet are the materials through which things cannot be seen. Hence, they both are opaque materials.

Translucent: The materials through which objects can be seen, but not clearly, are known as translucent.

i. Among the given options, muslin cloth is the material through which things can be seen but not clearly.

ii. Hence, it is a translucent material.

iii. On the other hand, glass tumbler is transparent.

iv. Mirror and aluminum foil are opaque.

The substances which are lighter than water float on water. Among the given options, feather and plastic ball are much lighter than water. Hence, they both float on water.

Wood, glass, leather are not used to make a safety pin. Steel and plastic are commonly used for making a safety pin.

Lustrous means shiny appearance. Wood is not lustrous. It has a dull appearance. On the other hand, gold, diamond, and silver are lustrous and shiny.

Materials are not grouped for fun. It is an incorrect statement. Materials are grouped for convenience, to study their properties and uses.

Among the given options, tawa, spade and pressure cook are hard materials. They cannot be squeezed, compressed, cut or bent.

On the other hand, the eraser is the odd one out which is a soft substance, can be squeezed, compressed, cut or bent easily.

For a front glass of a car, we need such a material through which things can be seen properly.

i. Transparent is the only material through which things can be seen.

ii. Opaque is the material through which things cannot be seen.

iii. Translucent is the material through which things can be seen, but not clearly.

iv. Thus, transparent materials should be used for making the front glass of a car.

Raveena

i. Red chili powder, butter (oil), petrol are lighter than water. Hence, they start to flow on the surface of the water.

ii. On the other hand, honey dissolves completely in the water. Hence, the mixture of honey and water were given to Raveena is in solution form.

yes

Shikha’s brother will be able to locate her because:

i. The glass material is a transparent material.

ii. Transparent is material through which all the light passes easily.

iii. Thus, things can be seen properly through glass material.

iv. As a result, the person standing behind it can be seen clearly.

i. The cotton ball is lighter than water.

ii. First, when it is placed in water, it starts to float on the surface.

iii. But after 10 mins, it absorbs water. As a result, it becomes heavier than water.

iv. Thus, it will sink in water after 10 mins.

Rubber band, leaf, eraser, cooked rice, and fresh chappati are soft materials.

Soft materials: Materials which can be compressed, bent, cut or scratched easily are called soft.

Rubber band, leaf, eraser, cooked rice, and fresh chappati can be compressed, cut, bent or scratched easily. Hence they are soft.

On the other hand, pencil, pearl, wooden board and pulses all are hard materials. They cannot be compressed or scratched easily.

Note:

Soluble – Some substances completely disappear in water. These substances are soluble in water.

Insoluble – Some substances do not mix with water do not disappear even after we stir for a long time. These substances are insoluble in water.

a) Aluminium

Uses of aluminium:

i. Aluminium is used to make foil paper.

ii. It is used for making electrical wires.

b) Plastic

Uses of plastic:

i. Plastic is used in making bottles.

ii. It is used in making buckets, mugs etc.

c) Kerosene

Uses of kerosene:

i. It used as lamp fuel when electricity is unavailable.

ii. It is used as a solvent.

d) Vinegar

Uses of vinegar:

i. It used as a food preservative.

ii. It is used in food ingredient.

i. The coin is heavier than water and things cannot be seen through it. Hence, it is opaque and would sink in water.

ii. Stone is heavier than water and things cannot be seen through it. Hence, it is opaque and would sink in water.

iii. The pencil is heavier than water and things cannot be seen through it. Hence, it is opaque and would sink in water.

iv. Eraser is also heavier than water and things cannot be seen through it. Hence, it is opaque and would sink in water.

v. Coal is heavier than water and things cannot be seen through it. Hence, it is opaque and sinks in water.

Chalk:

i. Chalk cannot be bent and compressed.

ii. It is rough on the surface.

iii. It is not lustrous and appears dull.

Iron:

i. Iron is a hard material.

ii. It cannot be bent, compressed and scratched.

iii. Its appearance is shiny.

Wood:

i. Wood is a hard material.

ii. It cannot be bent and compressed.

iii. Its appearance is dull

Aluminium:

i. Aluminium is a hard material.

ii. It cannot be bent and compressed.

iii. Its appearance is shiny.

Candle:

i. Candle is a soft material.

ii. It can be bent, compressed and scratched easily.

iii. Its appearance is dull.

Cotton:

i. Candle is a very soft material.

ii. It can be bent, compressed and scratched easily.

iii. Its appearance is dull.

Oxygen dissolved in water is important for the survival of aquatic animals and plants because:

i. Oxygen gas is completely soluble in water.

ii. Plants and animals need oxygen for respiration and for breath.

iii. Therefore, oxygen gas is very important for them for their survival.