Earth Science
Quarter 2 – Module 2:
Earth’s Internal Heat Sources
What I Know
Directions. Choose the letter of the best answer. Write the letter
of your answer on a separate sheet of paper.
1. The heat __________ from the crust down to the inner core due to several reasons.
Which of the following words will best complete the thought of the given
statement?
A. decreases
B. equals
C. increases
D. proportional
2. All the layers of the earth has its own properties and characteristics. Which
among the layers of the earth has the highest temperature?
A. Core
B. Crust
C. Lithosphere
D. Mantle
3. Different elements comprises the layers of the earth. Which layer of the earth has
the highest amount of molten state iron?
A. Core
B. Crust
C. Lithosphere
D. Mantle
4. Why is Earth considered as a thermal engine?
A. The main source of internal energy is the sun.
B. The moon gives energy to earth and convert it to thermal energy.
C. The pressure of the materials in the crust causes materials to be molten.
D. The main source of heat comes from the produced decay of some naturally
occurring isotopes from its interior.
5. What happened to the amount of heat from crust down to the core?
A. It is equal.
B. It becomes lower.
C. It becomes higher.
D. It is indirectly proportional.
6. Earth was formed about 4. 6 billion years ago. Which of the following pertains to
the process by which gasses and dust of cloud were attracted by gravitational
energy?
A. Accretion
B. Solidification
C. Gravitational pull
D. Planetesimal
7. It is not possible to know about the earth’s interior by direct observations
because of its huge size and the changing nature of its internal composition.
Which of the following will best describe the given sentence?
A. It is correct.
B. It is incorrect.
C. It depends upon the outer or inner core.
D. It cannot be determined due to the nature of Earth.
8. Which among the layers of the earth has the greatest pressure which causes
tremendous internal heat of the earth?
A. Crust
B. Mantle
C. Outer core
D. Inner core
9. There are several sources that contribute to the internal heat of the earth. Which
of the following is NOT a major process that contributed to Earth’s internal heat?
A. heat from radioactivity of radioactive isotopes within the Earth’s core
B. heat released by colliding particles during the formation of the planet
C. heat released as iron crystallized to form the inner core
D. heat from the sun since the beginning of Earth history
10. How did the Earth generate heat on its early stage of formation?
A. by radioactive decay
B. by gravitational pressure
C. by absorption of solar energy
D. by collision of the masses of gas and dust
11. Heat can be transferred from one plate of the earth to the other. What type of
heat transfer exists between the plate boundaries?
A. Radiation
B. Convection
C. Conduction
D. Thermal transfer
12. How do radioactive isotopes emit heat energy and contribute to Earth’s internal
heat?
A. by pressure freezing
B. by gravitational pressure
C. by preserving the primordial heat
D. by spontaneous radioactive decay
13. Why do some isotopes play a minor role in the production of heat in the interior
of the earth?
A. due to its abundance in the core
B. due to the heat it releases
C. due to chemical stability
D. due to its high energy capacity
14. What happened to the pressure inside the Earth as you go deeper?
A. The pressure is the same.
B. The pressure increases.
C. The pressure decreases
D. The pressure is unstable.
15. Why does Earth’s internal heat builds up due to gravitational pressure?
