SCIENCE 9 Q3

Lesson 1: Volcanic Eruption

Volcanoes

• is a vent or fissure in the planet's crust through which lava, ash, rock and gases erupt.

• This is also a mountain formed by the accumulation of eruptive products that extends down to a pool of magma between the crust and mantle.

How are Volcanoes formed?

1. Volcanoes are formed when magma from within the Earth's upper mantle works its way to the surface.

• At the surface, it erupts to form lava flows and ash deposits. Over time as the volcano continues to erupt, it will get bigger and bigger.

2. Volcanoes are formed from a subduction zone where two plates, one oceanic plate and one continental plate, collide.

• At a subduction zone, an oceanic plate submerges under a continental plate. The friction creates magma. When magma reaches the surface, then, a volcano is formed.

3. Volcanoes are formed when two plates move away from each other.

• Hot mantle rock rises into the space where the plates are moving apart. As the hot mantle rock convects upward, it rises higher in the mantle.

• Lava erupts through long cracks in the ground, or fissures.

Parts of a Volcano:

Magma Chamber

•  Lies inside the earth. Stores hot, melted rock called magma.

Central Vent

• Opening at the top of the volcano in which lava, pieces of rock and other materials pour out of.

Conduit

• Vertical channel or pipe in which magma moves up before it reaches the surface of the earth.

Crater

• Bowl-shaped hole which forms at the top of the volcano.

Lava Flow

• Lava is very hot when it erupts out of a volcano. The lava flows down the sides of the volcano. As it

moves, the lava cools and hardens. 

Magma VS  Lava

Magma

• Magma is composed of molten rock and is stored in the Earth’s crust.

• natural material from which all  igneous rocks are formed.

Lava

• is magma that reaches the surface of our planet through a volcano vent.

The Three Major Types of Volcanoes

According to Shape

Volcanoes are classified by:

• Their shape

• The way they erupt

• The materials from which they are formed

There are three main types of volcanoes that we need to learn about. They are:

• Cinder Cone Volcanoes

• Shield Volcanoes

• Composite Volcanoes

Cinder Cone Volcanoes

• Cone shaped with very steep sides

• Relatively small- usually less than 300m (984ft)

• Built from lava fragments called cinders

• Very little lava

Ex: Paricutin in Mexico and

Stromboli in Italy

Shield Volcanoes

• Looks like a shield

• Large mountains with  gentle slopes

• Formed from lava that flows slowly from a crack in the Earth’s crust

Ex: Mauna Loa located in Hawaii is the largest volcano on Earth

Composite Volcanoes

• Looks like and upside- down V and has steep sides

• Formed from the most explosive volcanoes

• Eruptions usually occur without warning and can be very destructive

• Layers of rock andlava

Ex: Mount Fuji which is located in

Types of Volcanoes According to Activity

1. Active

2. Dormant

3. Extinct

Active Volcanoes

• The volcano is still erupting quite regularly.

• erupted recently, and may erupt again soon.

• Volcanoes are classified as Active if it has

erupted recently and is likely to do so again. e.g. Mt Etna.

Dormant Volcanoes

• The volcano has not erupted for a long time but may erupt in the future.

• Volcanoes are classified as Dormant if it has not erupted for years, or even centuries, but still seeps gas sometimes. For example, Mt Pinatubo erupted in 1991 after 500 years of dormancy.

Extinct Volcanoes

• The volcano has not erupted in historic times and will not erupt again.

• Volcanoes are classified as Extinct if it has not erupted for thousands of years and its shape has been worn away by the wind and rain. e.g. Edinburgh.

The Pacific Ring of Fire

• Many of the world’s major earthquakes and many of the world’s active volcanoes occur in a zone that encircles the Pacific Ocean.

• This is because many of the world’s major plates meet here. Therefore, at this place the plates are pulling apart, pushing together and sliding past one another.

• This causes earthquakes and volcanoes to occur.

Our Changing Earth

Litospheric Plates - are the plates that comprise the fractured surface of the earth.

Lithospheric plates are of two types:

1. Continental Plates

2. Oceanic Plates 

• Earthquake and volcanic activity is common along the boundaries of Lithospheric plates.

Earth Movements - are divided on the basis of forces.

• Endogenic forces

• Exogenic forces

Endogenic Process

• the energy generating from within the earth is the main force behind the endogenic geomorphic processes.

Diastrophism 

Diastrophism: All process that move elevate or build up portions of the earth‟s crust

Volcanicity - The process through which gases and molten rock/ magma are either extruded on the earth's surface or intruded into the earth's crust.

Intrusive - magma cools, crystallizes, and solidifies into igneous rocks below the earth's surface. Slow cooling results in larger crystals e.g granite and dolerite.

Extrusive - magma surfaces as lava and cools, crystallises and solidifies through contact with air (fast) or the sea (rapid) into igneous rocks above the earths surface. Quicker cooling results in finer crystals e.g basalt.

Intrusive Volcanic Features

• Intrusive features form below the Earth’s surface, thus they only become part of the landscape once erosional processes have removed the overlying rocks. 

• Remember - these only surface once the rock layers above have been eroded! Over many years they solidify slowly within the Earth’s surface.

Dykes

• These are vertical intrusions formed where magma solidifies in a vertical crack/ fissure. 

• Dyke material tends to be more resistant than the surrounding rock leaving prominent wall-like features on an eroded landscape.

Sills

• These are horizontal intrusions formed where magma solidifies as sheets in between layers of existing rock. 

• When these are exposed at the surface through erosion, they form steep-sided cliffs along the landscape.

Laccoliths

• These are formed when thick viscous magma which is resistant to flow bulges and forces the overlying rock strata to arch into a dome.

Batholiths

• These are on a much larger scale than Laccoliths.

• Usually, dykes, sills and laccoliths will feed off the domed granite batholith before it solidifies.

Major Extrusive Volcanic Features

• Remember - these features which are eventually formed are dependent upon the material ejected during eruption. This may be gaseous, solid or liquid.

Gaseous Emissions

• Dominated by steam

• Often superheated

• Includes carbon monoxide, hydrogen sulphide, sulphur dioxide and chlorine.

Solids

•  Ash, dust, glassy cinders

• Shattered blocks of material which previously plugged the vent of the volcano

Liquids

• Lava bombs (tephra or pyroclasts) which solidify mid-air as pumice • Surface lavas which are acid or basic

Types of Lava

Basic or Basaltic Lava 

•  dominated by iron manganese and is low in silica. 

• Gas bubbles have freedom to expand as the magma rises to the surface. 

• Eruptions are fluid and free-flowing.

Andesitic Lava

• Medium in silica content. 

• Acid lava is medium in terms of viscosity.

• Temperature of eruption 750-950°C.

Acid or Rhyolitic Lava 

•  rich in silica. 

• Acid lava is so thick and viscous the gas bubbles struggle to expand. 

• This builds up pressure to create violent eruptions.

Aa 

• Forms when lava flows rapidly. 

Rapid heat loss - increase in viscosity.

Pahoehoe 

• forms when lava flows more slowly. 

• A well-developed skin can form - inhibits heat loss.

Fissures and Vents

Fissure Eruptions - Basic lava creates extensive lava plateaus.

Vent Eruptions - Create cone shaped landforms

Classification of Volcanoes

• Volcanoes are classified according to the violence of their eruption which is determined by the pressure and quantity of gas in the magma.

• Fissure

• Basic Shield Volcano

• Acid Dome Volcano

• Caldera

• Ash/Cinder Cone Volcano

• Composite Cone Volcano

Lesson 2.1 Earth's Geosphere

Geosphere - refers to the solid part of the Earth, including the rocks, minerals, landforms, and the processes that shape them. In this lesson, we will explore the earth's layers and how the plates of the earth move.

The Layers of the Earth

• The earth is divided into three main layers namely the crust, the mantle and them core. Understanding the different layers of the Earth helps us learn about whatmthe Earth is made of, how it is structured, and how it behaves.

Crust

• The crust is the outermost layer of the Earth. 

• It is the thinnest layer, ranging from about 5 to 70 kilometers in thickness. 

• The crust can be further divided into two types: continental crust and oceanic crust.

Continental Crust

• The continental crust is the thicker layer of the Earth's crust that is found under the continents. 

• It is about 35 kilometers thick on average.

Oceanic Crust

• The oceanic crust is the thinner layer of the Earth's crust that is found under the ocean basins.

• It is about 7 kilometers thick on average.

Mantle

• The mantle is the layer beneath the Earth's crust. 

• It is the thickest layer, extending from the base of the crust to a depth of approximately 2,900 kilometers. 

• The mantle can be divided into an upper and lower layer.

Upper Mantle

• The upper mantle is relatively rigid and contains the asthenosphere, a semi-fluid layer that allows the movement of tectonic plates.

Lower Mantle

• The solid lower mantle contributes to the overall convection and heat transfer within the Earth's interior.

Core

• The core is the innermost layer of the Earth, situated beneath the mantle. 

• It is divided into two distinct regions: the outer core and the inner core.

Outer Core

• The outer core is a liquid layer composed mainly of molten iron and nickel.

• It has a thickness of about 2,300 kilometers.

Inner Core

• The inner core is the solid, central part of the earth. 

• It has a radius of about 1,220 kilometers and is composed of solid iron and nickel.

Types of plate Boundaries

• Convergent Plate

• Transform Plate

• Divergent Boundaries

• At divergent boundaries, plates move away from each other. This movement results in the creation of new crust as magma rises from the mantle, solidifies, and forms new oceanic crust.

Divergent Boundaries

• Are responsible for the continuous reshaping and formation of Earth's crust.

• On land, divergent plate boundaries create rift valleys. 

• The crust in these areas stretches and thins, causing the land to sink and create a valley.  

Magma from the mantle can rise to the surface, leading to volcanic activity.

Convergent Boundaries

• Convergent boundaries are places where

tectonic plates collide or come together. 

• When two plates meet, their interactions

can result in various geological phenomena.

• Convergent boundaries contribute to the formation of mountains, volcanic activity, and earthquakes.

• When two continental plates collide, neither plate is subducted due to their low density. Instead, the two plates compress and crumple, creating highly folded and uplifted mountain ranges.

Transform Boundaries

• Transform boundaries occur when two plates slide past each other horizontally.

• The movement along these boundaries can cause earthquakes, as the plates grind against each other.

• Transform boundaries redistribute stress and accommodates the movement between neighboring plates.

Nine Useful Earthquake Preparedness Tips

01) Drop, Cover, and Hold On

• When you feel the shaking of an earthquake, drop down to your hands and knees. This position helps you stay balanced and prevent being knocked over.

• Take cover under a sturdy piece of furniture, such as a table or desk, to protect yourself from falling objects and debris.

• Hold on to your sheltered position and hold onto the furniture or other protective structure until the shaking stops.

02) Follow Evacuation Procedures

• If there is a specific reason to evacuate the building, such as a fire or a structural issue, follow the established evacuation procedures of the building or the guidance of emergency personnel. Move calmly and quickly to designated safe areas or assembly points.

03) Focus on Safety

• Panicking can cloud your judgment and impair your ability to think clearly. It may lead to irrational actions or decision- making that can increase the risk of harm to yourself and others.

• In an emergency, it is crucial to prioritize your safety and the safety of those around you. Panicking can distract you from taking necessary precautions and following proper safety procedures.

04) Follow Emergency Protocols

• During an earthquake, it is generally not advisable to use elevators or fire exits unless specifically instructed to do so by emergency personnel or building management.

• It's important to familiarize yourself with the emergency protocols and evacuationM procedures specific to your building or location and follow the guidance provided by authorities during an earthquake.

05) Glass Hazards

• During an earthquake, the shaking can cause windows to shatter or crack, leading to flying shards of glass. These broken glass pieces can cause severe injuries or lacerations if you are near the windows.

06) Watch for Overhead Hazards

• During an earthquake, buildings may experience structural damage, and there is a risk of falling debris, such as bricks, glass, or other materials. Being close to buildings increases the chance of being hit by falling objects, which can cause severe injuries.

• Posts, columns, or other vertical structures may also be vulnerable during an earthquake. They can topple or collapse, posing a danger to anyone nearby.

07) Participate in Earthquake Drills

• Participating in earthquake drills helps familiarize individuals with the proper actions and procedures to follow during an earthquake. It allows you to practice the "Drop, Cover, and Hold On" technique, evacuation routes, and other safety protocols specific to your location.

08) Immediate Access to Essentials

• Having emergency supplies in one place ensures that you can quickly access them during an emergency, even if regular services or supplies are disrupted.

• Having an emergency kit ready and easily accessible is essential for earthquake preparedness. It ensures that you have essential supplies readily available, empowering you to meet your basic needs and respond effectively during and after an earthquake or other emergency situations.

09) Be Updated

• Being updated on the latest information about potential hazards, such as earthquakes or other disasters, allows you to understand the risks associated with your location. This knowledge helps you make informed decisions regarding preparedness measures, evacuation plans, and safety precautions.

Lesson 2.2 Earthquakes

Lithosphere

• The lithosphere is broken into segments

called Tectonic Plates. These plates are moved by the hot plastic mantle beneath the lithosphere.

Tectonic Plates

• are large solid pieces o lithosphere

• Tectonic plates are constantly shifting as they drift around on the viscous, or slowly flowing, mantle layer below.

Earthquakes

• Sudden movement or vibration of Earth caused by the release of energy in rocks.

• Happens when two plates of the earth suddenly slip past one another

• Associated with faulting or breaking of rocks

What causes Earthquakes?

• When two plates meet and slides past or push against each other, pressure can build below the surface.

• Plates shift suddenly, pressure and energy are released, sending out waves that causes earthquakes.

Fault

• A planar fracture between two rocks facing each other.

• Caused by forces which may be vertical, horizontal, or inclined at an angle

Stress On Rocks

Tension - rocks move away from each other.

Compression - rocks move together.

Shearing - rocks slide past each other.

The Three Basic Types of Faults

Fault

• Fault Plane - a flat surface where slipping occurs

• Footwall - block located below a fault plane

• Fault Line - the trace of a fault boundaries on the surface of the Earth

• Fault Scarp - it looks like a step on the Earth's surface

• Hanging Wall – a side that moves downward

1. Normal Fault - 

• Moves vertically and is associated with diverging plates.

• Tension - weakens and fractures the Earth's crust causing the other block of rock to move downward relative to the other.

2. Reverse Fault

• Thrust fault

• Occurs when a plate below the ocean is moving under another plate, thrusting its edge upward

• Caused by compression which forces a fault block upward.

3. Strike-Slip Fault

• It occurs when two faults move past each other horizontally.

• Caused by “shearing”

How does movement of fault generate earthquake?

Stresses → Rock Slips → Release Energy → Shaking → Earthquake 

Magnitude - 

Focus or Hypocenter

• The point of origin of an earthquake.

• It is within the Earth's crust

Epicenter

• The point on the Earth's surface directly above the hypocenter.

Seismic Waves

• They are energy waves that travel either through the Earth's interior or along or near the Earth's surface.

      Body Waves 

        • Travel through the Earth's interior.

        • Example: P-wave and S-wave

Surface Waves

       • Travel across the Earth's surface

       • Example: L-wave

Seismograph

• An instrument that can record seismic waves.

• A less powerful earthquake is shown by short, wiggly lines.

• A powerful earthquake is shown by long wiggly lines.

Active Faults

• A fault is considered active if it has moved

repeatedly in the past and is likely to move again.

Inactive Faults

• A fault that has moved in the distant past and is unlikely to move again.

Lesson 3: Meteorology/Weather & Climate

Weather - refers to the short-term atmospheric conditions of a specific area, such as temperature, humidity, and precipitation.

Climate - describes the long-term

average of weather patterns over

decades or centuries in a region.

Two Major Factors that Affect Climate

1. Temperature

• Temperature determines how warm or cold an area is and is influenced by latitude, altitude, and proximity to water. It affects the type of flora, fauna, and human activities in a region.

2. Precipitation

• Precipitation, including rain, snow, and hail, determines water availability and shapes ecosystems. It is affected by factors such as wind patterns, ocean currents, and topography.

Latitude and Altitude in Temperature

Latitude - affects temperature as regions closer to the equator receive more direct sunlight. Areas near the poles experience cooler temperatures due to slanted sunlight.

Altitude - Altitude impacts temperature, with higher altitudes experiencing cooler temperatures. This occurs because the atmosphere becomes thinner with elevation.

Basic Elements of Weather and Climate

Temperature - A measure of how hot or cold the atmosphere is, influenced by solar energy and Earth's surface conditions. It affects daily life, agriculture, and energy consumption.

Rainfall - Is the water released from clouds due to condensation, critical for sustaining life. It varies widely across regions based

 on climatic factors.

Wind - Is the movement of air caused by differences in air pressure. It influences weather patterns and temperature distribution.

Wind and Its Factors

Air Pressure - How heavy the air is over a unit of area. Differences in air pressure create wind as air moves from high to low-pressure areas. It drives weather systems globally.

Air Mass and Air Temperature

• Air masses carry the temperature and moisture characteristics of their source regions. Interactions between warm and cold air masses cause weather changes.

Orographic Effect -  

• Occurs when moist air is forced to rise over mountains, cooling and condensing to form precipitation.

• The windward side receives

more rainfall, while the leeward

side becomes dry.

Greenhouse Effect - The greenhouse effect is the trapping of heat in Earth's atmosphere by gases like carbon dioxide and methane. It keeps Earth warm but excessive greenhouse gases lead to climate change.

How Greenhouse Effect Affects Us

• A stronger greenhouse effect results in global warming, leading to 

• rising sea levels and

• extreme weather.

• It disrupts ecosystems and threatens food security.

Global Warming - Refers to the long-term rise in Earth's average temperature due to human activities like burning fossil fuels. It causes melting ice caps, habitat loss, and severe climate changes.

How to Reduce Global Warming?

• Reducing emissions by adopting renewable energy, conserving energy, and planting trees helps combat global warming. International agreements and local actions play a vital role.

Renewable Energies

• Renewable energies like solar, wind, and hydropower generate electricity without depleting resources or emitting greenhouse gases. They are sustainable and essential for a clean future.

Lesson 4: Astronomy

Stars 

• A star is a luminous ball of gas, mostly hydrogen and helium, held together by its own gravity.

• Any massive self-luminous celestial body of gas that shines by radiation derived from its internal energy sources.

Characteristics of Stars:

• Brightness

• Color

• Surface Temperature

• Size

• Composition

1. Brightness

• Two characteristics define brightness:

luminosity and magnitude.

• Luminosity - is the amount of light that a star radiates. The size of the star and its surface temperature determine its luminosity.

• Apparent Magnitude of a star is its perceived brightness, factoring in size and distance, while  Absolute Magnitude is its true brightness irrespective of its distance from earth.

2. Color

A star's color depends on its surface

temperature.

Cooler stars tend to be redder in

color, while hotter stars have a bluer

appearance.

Stars in the mid ranges are white or

yellow, such as our sun. Stars can

also blend colors, such as

red-orange stars or blue-white stars.

Color and Temperature of Stars

3. Size

• As the mass of the star increases, its size will also increase.

• Stars are classified as dwarf, giant or super giant

Dwarf – are very small, about 75-80 percent the size of the sun.

Giant – twice to 10 times larger than the sun.

Super Giant – more than 10 times the size of the sun.

4. Composition

• Astronomers study the spectral lines detected by spectroscopes to determine the composition of stars.

• It is learned that all stars are composed of Hydrogen (60-80%), Helium (16-36%), and traces (4%) of oxygen, neon, carbon, and nitrogen.

Constellations - A constellation is a grouping of stars that represents one of the 88 divisions of the celestial sphere as defined by the International Astronomical Congress of 1928. Many constellations are derived from old traditional asterisms, which are star patterns within a constellation. 

Constellations in the Northern Hemisphere

• Constellations that can be seen all yearround are called circumpolar. In the northern Hemisphere, circumpolar  constellations are seen near the North Star

• Ursa Major, Ursa Minor, Cassiopeia, Cygnus

Constellations in the Souther Hemisphere

• There is no polar star as a reference point.

• Crux or Southern Cross, Carina, and Centaurus