Lesson.5 Interior of the Earth
Lesson.5 Interior of the Earth
I. Choose the correct answer
1. Nife is made up of _________.
- Nickel and ferrous
- Silica and aluminum
- Silica and magnesium
- Iron and magnesium
Ans : Nickel and ferrous
2. Earthquake and volcanic eruption occur near the edges of ___________.
- Mountain
- Plains
- Plates
- Plateaus
Ans : Mountain
3. The magnitude of an earthquake is measured by ___________.
- Seismograph
- Richter scale
- Ammeter
- Rotameter
Ans : Richter scale
4. The narrow pipe through which magma flow out is called a ___________.
- Vent
- Crater
- Focus
- Caldera
Ans : Vent
5. ___________ Volcano is known as light house of Mediterranean Sea.
- Stromboli
- Krakota
- mid – Arctic
- Kilimanaro
Ans : Stromboli
6. ___________ belt is known as the “Ring of Fire”.
- Circum – Pacific
- Mid – Atlantic
- Mid – Arctic
- Antarctic
Ans : Circum – Pacific
II. Fill in the Blanks.
1. The core is separated from the mantle by a boundary called _________.
Ans : Welchart- Gutenbery discontinuity
2. The earthquake waves are recorded by an instrument known as _________.
Ans : seismograph
3. Magma rises to the surface and spreads over a vast area is known as _________.
Ans : fissure eruption
4. An example for active volcano is _________.
Ans : St.Helens USA
5. Seismology is the study of _________.
Ans : earthquakes
III. Circle the odd one
1) crust, magma, core, mantle
Ans : magma
2) focus, epicenter, vent, seismic waves
Ans : vent
3) Uttar Kashi, Chamoli, Koyna, Krakatoa
Ans : Krakatoa
4) lava, caldera, silica, crater
Ans : silica
5) Stromboli, Helens, Hawaii, Fujiyama
Ans : Fujiyama
IV. Match the following
| 1. Earth quake | Japanese term |
| 2. Sima | Africa |
| 3. Pacific Ring of Fire | Sudden movement |
| 4. Tsunami | Silica and magnesium |
| 5. Mt. Kenya | World volcanoes |
| Ans : 1 – C, 2 – D, 3 – E, 4 – A, 5 – B | |
V. Consider the following statement and tick ( √ ) the appropriate answer.
1. Assertion (A) : There structure of the earth may be compared to that of an Apple.
Reason (R) : The interior of the earth consists of crust, mantle and core.
- A and R are correct and A explains R.
- A and R are correct but A does not explain R.
- A is incorrect but R is correct.
- Both A and R are incorrect.
Ans : A and R are correct and A explains R.
2. Assertion (A) : ThePacific Oceanincludes two thirds of the world’s volcanoes.
Reason (R) : The boundary along the Eastern and Western coast areas of the Pacific Ocean is known as the Pacific Ring of Fire.
- A and R are correct and A explains R.
- A and R are correct but A does not explain R.
- A is incorrect but R is correct.
- Both A and R are incorrect.
Ans : A and R are correct and A explains R.
VI. Answer in a word.
1. Name the outer most layer of the earth.
Crust.
2. What is SIAL?
Silica and Alumina.
3. Name the movement of the Earth’s lithospheric plates?
Tectonic movements.
4. Give an example of extinct volcano.
Mt. Kilimanjaro and Mt. Kenya of Africa.
VII. Answer the following briefly.
1. What is mantle?
The next layer beneath the crust is called the mantle.
2. Write note on the core of the earth.
The innermost layer of the earth is called the core. It is also known as barysphere.
3. Define Earthquake.
A sudden movement of a portion of the earth’s crust which produces a shacking or trembling is known as an earthquake.
4. What is a Seismograph?
The earthquake waves are recorded by an instrument known as seismograph.
5. What is a volcano?
A Volcano is a vent or an opening in the earth’s crust through which hot magma erupts from deep below the surface.
6. Name the three types of volcanoes based on shape.
- Shield Volcano
- Cinder-cone Volcano
- Composite Volcano
VIII. Give reason.
1. No one has been able to take samples from the interior of the earth.
It has very high temperature and pressure.
2. The Continent crust is less dense than the oceanic crust.
- The continental crust is composed mostly of granite. The oceanic crust is composed mostly of basalt.
- The basalt rock is heavier than the granite.
IX. Distinguish between.
1. SIAL and SIMA.
| SIAL | SIMA |
| 1. It has the main mineral constituents are Silica and alumina. | It has the main mineral constituents are Silica and magnesium. |
| 2. So it is collectively called SIAL. | It is therefore called SIMA. |
2. Shield volcano and composite volcano.
| Shield Volcano | Composite Volcano |
| 1. It is formed by quiet eruption of lava with a low silica content. | It is made of alternate layers of lava, cinder and ash. |
| 2. This Volcano has a wide base and a cone with gentle slopes. | They are also called Strato Volcano. |
| Eg: Hawaii islands. | Eg: St. Helens. |
3. Active volcano and dormant volcano.
| Active volcano | Dormant volcano |
| 1. They erupt frequently. | They have shown no sign of activity for many years but they may become active at any time. |
| 2. There are 600 active volcanoes in the world. Most of the active volcanoes lie in the Pacific Ring of Fire belt which lies along the Pacific coast. | It is also called sleeping volcano. |
| Eg: Mauna Loa in Hawaii is the world’s biggest active volcano. | Eg: Mt. Fujiyama in Japan. |
X. Answer the following questions in detail.
1. Write about the effects of an earthquake.
- Earthquake may cause changes in the earth’s surface.
- Vibration after set land slides in mountain regions.
- Most of the houses which collapsed were of mud and bricks are proved to be death traps.
- Fire is another great danger underground water system is disturbed.
- The floods and waves (Tsunami) caused great loss of life.
2. Describe the classification of volcanoes based on the eruptions.
- Active volcanoes
- Dorm ant volcanoes
- Extinct volcanoes
Active volcanoes:
They erupt frequently. Most of them lie in the Pacific Ring of Fire belt which lies along the Pacific coast.
Eg: Mauna Loa in Hawii.
Dormant volcanoes:
They have shown no sign of activity for many years but they may become active at any time.
Eg: Fujiyama in Japan.
Extinct volcanoes:
The top of extinct volcanic mountains have been eroded.
Eg: Mt. Kilimanjara in Africa.
3. Name the major zones of volcanic activity and explain any one.
- The Circum – Pacific belt.
- The Mid continental belt.
- The Mid Atlantic belt.
The Circum Pacific belt:
- This is the volcanic zone of the convergent oceanic plate boundary.
- It includes the volcanoes of the eastern and western coasted areas of Pacific Ocean.
- This zone is popularly termed as the Pacific Ring of fire.
- It includes two thirds of the world’s volcanoes.
XI. HOTs.
1. The earth’s interior is very hot. Why?
- Radio activity with in the core due to nuclear fusion results in generation of heat.
- The weight of the over lying materials exerts great pressure on the core resulting in to high temperature.
2. Are Volcones Destructive (or) Constructive?
Volcanoes are both destructive and constructive. They are constructive because cooled Lava is good for the soil. Volcanoes are destructive because the Lava can start fires and burn things like houses, trees and people.
3. How does volcaone make on Island?
- Volcanoes can also form in the middle of a plate, where magma rises upward until it erupts on the sea floor, that is called “hot spot”.
- The Hawaiian islands were formed by such a hot spot occurring in the middle of the Pacific Plate.
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