Question

4. Give reasons.
(i) We cannot go to the centre of the earth.
(ii) Sedimentary rocks are formed from sediments.
(iii) Limestone is changed into marble.
5. For fun.
(i) What are the minerals most commonly used in the following objects?
(ii) Identify some more objects made up of different minerals.​

Answer 1

Answer:

(i) To reach the centre of the earth one will have to dig a hole 6000 6000km deep on the ocean floor. This is quite impossible and therefore we cannot go to the centre of the earth.

(ii) Rocks break down into small fragments known as sediments. These sediments are transported and deposited by wind, water, etc. These loose sediments are compressed and hardened to form layers of rocks known as sedimentary rocks.

(iii) Limestone is changed into marble as a result of metamorphism under great heat and pressure.

5) 2 nd

ii) Pencil lead is made of graphite. Telephones have copper wiring. Carpets in our homes contain sulphur and chromite. Clocks are made of Quartz and Pentlandite. Toothpaste is made white with titanium oxide which comes from minerals called rutile, ilmenite, and anatase.

Answer 2

Explanation:

4.

(i) Since the temperature and pressure increase enormously as we go deeper and deeper inside the earth, we cannot go to the centre of the earth.

(ii) Because of extreme compression and hardening of the particles of sediment which are deposited by wind, water etc.

(iii) Because of extreme heat and pressure, limestone undergoes a change in its form and turns into marble.

5.

(i) iron, copper,silver,gold,brass,etc.,

(ii) ) Pencil lead is made of graphite. Telephones have copper wiring. Carpets in our homes contain sulphur and chromite. Clocks are made of Quartz and Pentlandite. Toothpaste is made white with titanium oxide which comes from minerals called rutile, ilmenite, and anatase.

i hope it is useful..