Unit 3, Module 1 Volcanoes

1. VOLCANO

2. •Have you seen a real volcano?
•In a picture or in a television?
•What can you say about a
volcano? (describe)
•Would you wish to live in a place
where there is a volcano?

3. Read the introduction in page 163.
Questions: oral
1. Does Philippines has many volcanoes? Why?
2. What is the most famous volcano in our country?
3. When did it last erupted?
4. How the terrible eruption of Pinatubo Volcano had
drawn to history?
5. What is PHIVOLCS?
6. Why do we need to study about volcano?
• Bring colored pens, and ruler next meeting for the 1st
activity.

5. VOLCANO
- is a natural opening or vent in
the surface of the Earth
usually in a mountainous form
with a magma chamber
attached to the mantle of the
planet.

6. External Parts of a Volcano
summit
slope
base

7. At the summit, there is an opening
which may either be a crater or a
caldera. A crater is a funnel-shaped
opening at the top of a volcano
while a caldera is formed when a
part of the wall collapses following
an explosive eruption.

9. Volcanoes come in different shapes
and sizes, and each structure has a
unique history of eruption. However
, volcanologists have been able to
classify them.

10. Volcanoes are classified according to:
A. Record of eruption
Active – are those that have record of eruption
within the last 600 years or those that
erupted 10,000 years ago
Inactive – those that have not erupted for the last
10,000 years and their physical form is
being changed by agents of weathering
and erosion through formation of deep
and long gullies

11. Perform Activity 2 in your
activity notebook as Activity
3.1 found in page 166 entitled
“Volcanoes in The Philippines”
.

12. WHAT CAUSES VOLCANOES TO
ERUPT?
Volcanoes Under Pressure (2).mp4

13. Magma inside the volcano has high temperature.
As the magma is continuously heated, it goes up.
As it rises, gas bubbles are developed. The gas
bubbles are trapped and expanded causing the
molten material to swell also, resulting into a
gradual increase in pressure within the volcano.
When the pressure exceeds the strength of the
overlying rock, fracturing occurs. The resulting
breaks lead to a further drop in confining pressure,
which in turn causes even more gas bubbles to

14. •Lava is a molten rock erupted at the
ground surface. When molten rock is
beneath the ground, it is called magma.
Magma is composed mainly of a mixture
of molten rocks, water, carbon dioxide
and other dissolved gases.

15. B. Shape of volcanic cone
Shield - are formed by accumulation of
lava that oozes out from the
volcano
cinder - are built from ejected lava
fragments.
composite / stratovolcano - has a nearly
perfect sloped structure formed
from alternate pyroclastic
deposits.

16. B. Shape of volcanic cone
Shield Cinder Composite

17. Volcanic cones are affected or influenced by the type
of its eruptive style.
Primary Factors affecting the Volcanoes’ Eruptive
Style
1. magma’s temperature
2. chemical composition of the magma
3. amount of dissolved gases

18. These factors can affect the magma’s viscosity in
different ways.
Viscosity – is the property of the materials resistance
to flow. It is described as the liquid’s
thickness and stickiness.
- The more viscous the material is, the
greater is its resistance to flow.
Ex. Honey is more viscous than water. How to test the Viscosity of a Liquid
(1).mp4

19. Primary Factors affecting the Volcanoes’ Eruptive Style
1. magma’s temperature - the higher the temperature of magma
is, the lower its viscosity is.
- As lava flows, it cools and begins to
harden, its ability to flow decreases
and eventually stops

20. 2. chemical composition of the magma
- magmas with high silica content are more
viscous than those with low silica content .
- The magma that contains less silica is
relatively fluid and travels far before solidifying
3. amount of dissolved gases
- gas (mainly water vapour) dissolved in magma
tends to increase its ability to flow. Therefore, in
near-surface environments, the loss of gases makes
magma more viscous, forming a dome or a columnar

23. ENERGY FROM THE VOLCANO
Geothermal Energy – the heat from the Earth’s interior
Since our country is a home to more than a hundred
volcanoes, energy has been tapped from them. Philippines
ranks second in the world’s production of geothermal energy.
According to the Department of Energy, 14.4 % of the
country’s total power generation is produced from
geothermal energy. The production of electricity from
geothermal energy is cheaper than the electricity production
using natural gas, coal, and hydropower.

24. How is geothermal energy generated?
Two ways on generating geothermal energy:
1. Geothermal power plants
2.Geothermal heat pumps
These two ways on generating geothermal energy differ in
the depth of heat source to produce energy.
In geothermal power plants, the heat from deep inside
the earth is used to produce steam to generate electricity
compared with geothermal heat pumps that use the heat
coming from close to the earth’s surface to heat water or
provide heat for buildings.

25. Power plants are built in an area where it is
particularly hot just below the surface such as near a
group of geysers, hot springs, or volcanic activity.
In the Philippines, geothermal power plants are
used to generate electricity in Tiwi (Albay), Kidapawan
(North Cotabato), Calaca (Laguna), Tongonan (Leyte),
Bago City (Negros Occidental), Valencia (Negros
Occidental), and Bacon (Sorsogon).

26. STEPS TO GENERATE ELECTRICITY IN A GEOTHERMAL
POWER PLANTS
1. Wells are drilled deep into the earth to pump steam or hot
water to the surface.
2. When the water reaches the surface, the drop in pressure
causes the water to turn into steam.
3. The steam spins a turbine which is connected to a generator
that produces electricity.
4. Cooling tower cools the steam which it condenses back to
water.
5. The cooled water is pump back into the earth to begin the
process again.

27. How do volcanic eruptions affects society?

29. REFERENCES:
• Science 9 Learner’s Module, Republic of the Philippines Department of Education, FEP
Printing Corporation, First Edition, 2014
Disclaimer:
• Pictures and videos come from different internet websites.

30. We breathe and live all
for GOD’s Glory!!!! 
THANK YOU! 