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WorksheetsTHIRD Quarter Science 8 Exam
Total questions: 51
Worksheet time: 26mins
What is the approximate proportion of the Earth's surface covered by water?
About 25%
About 50%
About 70%
About 90%
If approximately 70% of the Earth's surface is covered by water, what major component covers the remaining proportion?
Ice sheets and glaciers
Land (continents and islands)
Atmospheric gases
Deserts
What is the outermost and thinnest layer of the Earth, which is composed of solid rock?
Mantle
Core
Crust
Hydrosphere
Which upper crustal layer is best described as the dense, iron and nickel-rich center of the Earth?
Crust
Mantle
Outer Core
Inner Core
A secondary source describes a layer of the Earth that is mostly solid but behaves like a very viscous fluid over geologic timescales. Which layer is being described?
Outer Core
Inner Core
Mantle
Crust
Based on the gathered information from secondary sources, why is the Outer Core a source of the Earth's magnetic field?
Because it is solid iron.
Because it is mostly silica.
Because it is composed of molten iron and nickel, creating convection currents.
Because it is the hottest layer.
Which type of volcano is known for its broad, gently sloping cone built from layers of fluid, low-viscosity lava flows?
Composite Volcano
Cinder Cone Volcano
Shield Volcano
Stratovolcano
What is the term for a small, steep-sided volcano built primarily from pyroclastic materials (fragments of lava) ejected from a single vent?
Shield Volcano
Cinder Cone Volcano
Composite Volcano
Submarine Volcano
Why are Composite Volcanoes considered the most dangerous type?
They erupt constantly, causing pollution.
They are always found near populated areas.
They are associated with highly viscous magma that can cause violent, explosive eruptions.
They are made mostly of loose ash.
Mount Mayon in the Philippines is an example of a Composite Volcano. What does its symmetrical, steep-sided cone indicate about its formation?
It was formed solely by fluid lava flows.
It was formed by a single massive eruption.
It was formed by alternating layers of lava flows and pyroclastic materials.
It was formed underwater.
An archaeologist discovers a volcano with a small, circular shape and very steep slopes made of loose, gravel-sized rocks. What action can the archaeologist immediately suggest based on its type?
It is a source of abundant geothermal energy.
It has an active lava lake.
It is a Cinder Cone and will likely not have large, widespread lava flows.
It is highly likely to produce pyroclastic flows.
The eruption of a volcano resulted in a massive, flat, and widespread flow of lava that covered a large area. Which type of volcano most likely produced this event?
Cinder Cone, because it is the smallest type.
Composite Volcano, because they are the largest.
Shield Volcano, because its magma has low viscosity and flows easily.
Caldera, because it is the biggest structure.
The viscosity of magma, which determines how easily it flows, is primarily influenced by its content of what compound?
Iron
Water
Magnesium
Silica
What type of magma is characteristic of a Shield Volcano?
High-silica, high-viscosity
Low-silica, low-viscosity
Medium-silica, medium-viscosity
Andesitic magma
Why does high-viscosity magma lead to the formation of steep-sided volcanic cones?
It flows very quickly and spreads out.
It contains less gas, which makes it stable.
It flows slowly and solidifies quickly, piling up near the vent.
It contains more iron and nickel.
Which cone shape is associated with a volcano composed mainly of alternating layers of andesitic lava and ash?
Broad and gently sloping
Small and very steep
Tall, symmetrical, and steep-sided
Flat and dome-like
A team of geologists studying a new volcano finds that its magma is rich in dissolved gases and has a high silica content. Based on this observation, what prediction can they make about the volcano's future shape?
It will become a Shield Volcano due to fluid lava.
It will become a Cinder Cone due to quiet eruptions.
It will likely become a Composite Volcano with a steep, tall cone.
It will collapse into a caldera.
A volcano is characterized by its broad base and gentle slopes. This shape most likely suggests that the volcano is primarily composed of what material?
Basaltic lava flows with low viscosity.
Pyroclastic materials and volcanic ash.
Granite and other intrusive rocks.
Water vapor and volcanic gas.
What general type of atmospheric disturbance is a typhoon?
Cold front
Tropical cyclone
Blizzard
Tsunami
Why does the Philippines experience a large number of typhoons each year?
Because it is located near the North Pole.
Because it faces the Pacific Ocean, where most tropical cyclones form.
Because it has many volcanoes.
Because it is close to the equator.
A weather report states that the sea surface temperature in the Western Pacific is significantly higher than normal. What is the most likely consequence?
A decrease in typhoon formation.
Typhoons will immediately dissipate upon reaching land.
An increased likelihood of tropical cyclone formation and intensification.
Typhoons will only form over land.
Why is warm, moist air an essential factor in the development of a typhoon?
It slows down the storm's rotation.
It increases the storm's central pressure.
It provides the heat and latent energy needed for the storm to continuously intensify.
It causes the typhoon to change its direction.
What is the calm, relatively clear central area of a strong typhoon called?
Rain band
Storm surge
Eye
Spiral Arm
Which part of the typhoon experiences the strongest winds and heaviest rainfall?
The outer rainbands
The central eye
The eyewall
The periphery
A weather station reports a typhoon with sustained winds of 120 kph. Based on this characteristic, what classification would PAGASA typically assign to this tropical cyclone?
Tropical Depression
Tropical Storm
Typhoon (The classification is generally 118-220 kph)
Super Typhoon
Why do the winds in a typhoon rotate inward and upward in the Northern Hemisphere?
Due to the centrifugal force.
Due to the effect of the landmasses.
Due to the Coriolis effect, which deflects the
How do the winds in a typhoon rotate inward and upward in the Northern Hemisphere?
Due to the centrifugal force.
Due to the effect of the landmasses.
Due to the Coriolis effect, which deflects the winds to the right (inward) and the low-pressure center.
Due to the high-pressure system at the center.
When a typhoon moves over a large landmass, what usually happens to its intensity?
It remains the same.
It intensifies rapidly.
It weakens rapidly.
It changes its direction suddenly.
How do warm bodies of water, like the Philippine Sea, influence the intensity of a typhoon?
They slow down the rotation of the storm.
They cause the typhoon to dissipate.
Prepare for an increase in the storm surge.
Expect the typhoon to stall over the mountain range.
A typhoon is predicted to cross a large, mountainous island before reaching the mainland. What is the most appropriate action to anticipate based on the impact of the landmass?
Prepare for immediate intensification of the storm.
Anticipate a weakening of the storm due to friction and reduced moisture supply.
Prepare for an increase in the storm surge.
Expect the typhoon to stall over the mountain range.
Which precautionary measure should be done BEFORE a typhoon strikes?
Secure or bring inside all outdoor objects.
Turn off the main power switch immediately.
Start boiling water for drinking.
Evacuate to higher ground.
Why is it important to stay away from the coastal areas DURING a typhoon?
To avoid being hit by falling debris.
To avoid lightning strikes.
To avoid the danger of a storm surge and massive waves.
To avoid heavy rainfall.
If a local government unit issues an evacuation order, what is the most appropriate action a resident should take?
Wait for the typhoon to pass before deciding.
Proceed immediately to the designated evacuation center.
Stay at home and secure all windows.
Only evacuate if the house is damaged.
Why is it a good practice to prepare a battery-operated radio and flashlight BEFORE the storm?
To communicate with family members far away.
To serve as a toy for children during the blackout.
To monitor important weather updates and have light in case of a power outage.
To help in cooking food during the storm.
Which government agency in the Philippines is primarily responsible for issuing weather advisories and storm signals?
DOST
DENR
NDDRMC
PAGASA
What does the raising of a Tropical Cyclone Wind Signal (TCWS) mean?
The typhoon has already passed the area.
The area is expected to experience strong winds and heavy rainfall within a specified time.
The weather is improving and safe to go outside.
All flights have been cancelled globally.
An area is under TCWS #3. Based on the signal, what is the most appropriate response regarding school classes?
Classes for all levels are suspended in private schools only.
Classes for all levels are automatically suspended in the affected area.
Classes for elementary and high school are suspended, but college classes continue.
Only preschool classes are suspended.
What is the term for the periodic rise and fall of sea level caused by the gravitational forces of the Moon and Sun?
Waves
Currents
Tides
Storm Surge
Which celestial body has the GREATEST influence on Earth's tides?
The Sun
The Moon
Mars
Jupiter
Why does the Moon have a greater gravitational effect on Earth's tides than the Sun?
The Moon is heavier than the Sun.
The Sun's gravitational pull is cancelled out by Earth's.
The Moon is much closer to the Earth than the Sun.
The Moon is larger than the Sun.
What is a Spring Tide?
A tide that occurs only during the Spring season.
A tide with the least difference between high and low water.
A tide with the greatest difference between high and low water.
A tide that occurs only when the Sun is at its highest point.
During a full moon, the Earth, Moon, and Sun are aligned. What type of tide will occur?
Neap Tide
Spring Tide
High Tide
Low Tide
If the Moon is at its first-quarter phase, why are the tides observed to be weaker (Neap Tides)?
The Moon is too far away from the Earth.
The gravitational forces of the Moon and Sun are acting at right angles, partially canceling each other out.
The Sun is directly overhead, reducing the Moon's effect.
The Earth is spinning too fast at this time.
A fisherman plans to harvest shellfish which are easiest to find during the lowest water level. Which lunar phase is the best time for him to go out?
First-quarter moon
Last-quarter moon
New Moon
Crescent moon
Approximately what percentage of the Earth's total water volume is saltwater, found mainly in the oceans?
50%
75%
97%
3%
Where is the majority of Earth's freshwater stored?
Rivers and Lakes
Underground aquifers
Ice caps and glaciers
The atmosphere
Why is the large proportion of the Earth's surface covered by saltwater not readily usable for human consumption?
Because saltwater is too cold to drink.
Because it is highly polluted by human activities.
Because the high salt content makes it unsuitable for drinking and most agricultural uses.
Because most of it is inaccessible.
Only about 3% of the Earth's water is freshwater. Why is a significant portion of this freshwater still inaccessible to humans?
It is all contained in the clouds.
It is too far below the Earth's surface.
It is locked up in ice caps and glaciers.
It evaporates too quickly.
A local government plans to tap into underground water sources for a new water supply system. What type of water source are they planning to utilize?
Oceanic water
Glacial water
Groundwater (Aquifers)
Atmospheric water
Despite the vastness of the oceans, why is the overall health of these bodies of water critical to global climate stability?
Because the oceans control the Earth's magnetic field.
Because the oceans produce all the oxygen we breathe.
Because the oceans absorb a vast amount of carbon dioxide and regulate global heat distribution.
Because the oceans are the only source of wind.
Based on the understanding of the Earth's water distribution, what is the best strategy to ensure a sustainable supply of potable water for future generations?
Invest heavily in water conservation, desalination technology, and protecting freshwater ecosystems.
Use all available groundwater as quickly as possible.
Rely only on rainfall.
Stop all forms of agriculture.
