EARTH SCIENCE
LAYERS OF EARTH
Four Main Layers of Earth
1. Crust
2. Mantle
3. Outer Core
4. Inner Core
1. Crust thin outermost layer
- includes land, mountains, oceans and soil.
- sites of human activity and geological processes (earthquakes and volcanic eruption)
- Cool and brittle
Two types:
a. Continental crust
b. Oceanic crust
a. Continental crust under land (thicker)
-composed of granite
b. Oceanic crust under ocean (thinner)
-composed of basalt
2. Mantle the thickest layer
-located below the crust
- extending about 2900 km (1800 miles) deep
-makes up about 84% of Earth's volume
-made of hot, semi-solid rock (magma)
- divided into upper mantle (solid)and lower mantle (denser and semi-fluid)
- composed of silicate rocks rich in iron and magnesium
Important Concept:
-mantle slowly moves in a process called convection currents.
These movements cause:
•Earthquake
• Volcanoes
• Movement of Continents
› The egg white
3. Outer Core - the liquid layer
- surrounds solid inner core
- composed of liquid iron and nickel.
about 2.300 km (1400 miles)
- Very hot (4.000-5000°C)
why it matters:
- convection currents here generates
Earth's magnetic field through the geodynam
> The runny yolk
4. Inner Core (Solid center)
- composed of iron and nichel
-radius about 1,220 km (760 miles)
- it is solid bc cause of extreme pressure
- the hottest layer (5,700°C) as hot as sun's surface
* celcius to fahrenheit (Nx9/5)+32
> The hard boiled egg
SUN
Solar System - the sun and everything
that or bits around it due to gravity.
•The sun
Sun
- huge, glowing ball of hot gas at the center of our Solar System
-Provides light and heat
-a star
-mastly made of hydrogen and helium
- 4.6 billion years old
- contains 99.8% of the Solar System's mass
• What makes the sun shine?
- because of a process called nuclear fusion in its core
Nuclear fusion - nydrogen atoms combine to form nelium, radewing a huge amount of energy
-> The energy travels outwards and becomes:
Sunlight (light energy)
Heat (thermal energy)
• Layers of the Sun
1. Core
- the center
- 15 million °C
- where nuclear fusion happens
2. Radiative Zone
- energy slowly moves award as radiation
3. Convective zone
- hot gas rises, cool gas sinks (like boiling water)
4. Photosphere
- the surface we see
- 5,500 °C
5. Chromosphere
- thin reddish layer above the surface
6. Corona
- outer most layer
- very hot and visible during solar eclipse
• Why is the sun important?
- powers photosynthesis
- drives weather and dimate
- keeps water in liquid form
- provide energy for humans and animals
• Fun Facts!
- light from sun takes 8 mins to reach Earth
- sun is about 109 times wider than Earth
- You could fit about 1 million earths inside the sun
*Looking directly at the sun can damage your eyes.
PLANETS
1. Mercury
- closest to the sun
- hot at day, freezing at night
- no atmosphere
- smallest planet
- has no moon
- travels around the sun in 88 days
2. Venus
- hottest planet
- thick, toxic atmosphere (carbon dioxide)
- spins backwards
- twin sister of earth (close size) earth is larger
- has more than 1,600 volcanoes
- atmosphere contains methane and sulfur
- greenhouse is bad from earth
3. Earth
- only planet to support life
- has liquid water
- has one moon
*There should be five terrestrial planet, Theia is fifth
-Theia has same orbital path from earth so they collide
4. Mars
- the red planet
- largest volcano: Olympus Mons
- evidence of past water
- second smallest planet
- has two moons (Deimos, Phobos)
- has deepest canyon (Valles Marineris)
- located to goldilock zones
* Goldilock zone - right temperature.
Jovian
- outer planets
- no solid surface
- gas and ice giants
- can hold large amount of moons.
- supports ring system
5. Jupiter
- largest planet
- gas giant made mortly of hydrogen and helium
- famous for Giant Red Spot (a giant storm)
- 79 moons
- 4 largest moon discovered by Galileo (Ganymede, Callisto, Io, and Europa)
- Brown dwarf (failed star)
- can fit 8 planet earth in red spot
6. Saturn
- known for its beautiful rings
- another gas giant
- less dense than water
- 62 known moon
- Second largest
7. Uranus
- ice giant
- rotates on its side (extreme filt)
- blue and green due to methane.
- only planet with tilted akis
- 27 moons satellites
- smallest Jovian
8. Neptune
- farthest planet
- strongest wind in the Solar System
- deep blue color
- 14 known moons
- great dark spot (same size as earth)
CELESTIAL OBJECTS AND CELESTIAL MOVEMENT
° Celestial Objects
• Stars
- massive, luminous spheres of plasma held together by gravity.
• Planets
- celestial bodies orbiting a star, massive enough to be rounded by their own gravity
• Moons (Satellites)
- objects orbiting the planet
• Asteroids
- rocky bodies orbiting the sun
- found in asteroid belt
• Comets
- icy bodies that release gas or dust
- has a nucleus, coma, and sometimes a tail
- develop glowing tails when near the sun
• Meteoroids
- small particles from comes or asteroids
• Galaxies
- massive systern of stars, stellar remnants, interstellar gas, dust, and dark matter, bound together by gravity
• Nebulae
- clouds of gas and dust in space, often regions where new states are born
° Celestial movement
Rotation
- spinning of celestial body on its axis
Revolution
- orbit of celestial body around another
Orbital Eccentricity
- describes how ellipticals (oval) an orbit is
MOON PHASES
Moon phases
- different shapes of the moon we see from Earth
-> The moon doesn't produce its own light - it reflects light from the Sun
- > As the moon moves, we see different portions of its lit side, creating phases.
• Why do Phases happen?
- because of the changing positions of:
the Earth, Moon, and Sun
As the moon orbits Earth (about 29. 5 days), the angle of sunlight changes—so Moon appears to change shape.
• The 8 Main Phases of the Moon
1. New Moon
- moon is between Earth and Sun
- we can't see it (dark side faces us)
2. Waxing crescent
- a small curved eliver appears
- "waxing" = growing
3. First Quarter
- half of the moon is visible
- looks half-circle
4. Waxing Gibbous
- more than half is lit
- growing toward full
5. Full Moon
- earth is between sun and moon
-entire face is bright
6. Waning Gibbous
- shrink after full
- "waning" = shrinking
7. Last (Third) Quarter
- half is visible but opposite side from first quarter.
8. Waning crescent
- thin sliver before disappearing
- > The phases repeat in a cycle called the Lunar Cycle
* Waxing = growing (right side bright in Northern Hemisphere like PH)
* Waning =shrinking (left side bright)
• Why it maters
- Moon Phases affect:
• tides (strongest during new and full)
• cultural calendars
• night brightness
PLATE TECTONICS EARTHQUAKES, VOLCANOES, AND THEIR THEORIES
• Plate Tectonics
- theory that Earth's outer layer (lithosphere) is broken into large picces called tectonic plates that move slowly.
- like a cracked eggshell—the pieces (plates) float on a softer layer underneath called the asthenosphere
•Key idea
- these plates are constantly moving
(a few cm per year), and their movement causes:
□ Earthquakes
□ Mountain Formation
□ Volcanoes
• Theories Behind Plate Tectonics
1. Continental Drift Theory
- proposed by Alfred Wegener
- suggested that continents were once joined into a supercontinent called Pangaea.
- Over million of years, they drifted apart
Evidence:
- puzzle-like fit of continents (e.g. South america and africa)
- similar fossils found on different continents
- matching rock formations
Problem: He couldn't explain how continent moved.
2. Seafloor Spreading theory
- proposed by Harry Hess
- new crust forms at mid-ocean ridges
- magma nises cools, and pushes older crust away.
Key result: oceans get wider over time.
3. Plate Tectonic Theory (Modern Theory)
- combines earlier ideas
- plates move due to mantle convection currents (heat from Earth's interior causes movement)
- explains earthquakes, volcanoes, and mountain building.
• Types of Plate Boundaries
1. Divergent Boundary (Pulling apart)
- plates move away from each other.
- magma rises
- forms new crust
Example: Mid Atlantic Ridge
- Causes volcanoes
2. Convergent Boundary (Colliding)
- plates move toward each other
Three outcomes:
a. Oceanic + Continental - volcanoes
b. Oceanic Oceanic island ares
c. Continental + Continental -> Mountains
Example: Himalayas
3. Transform Boundary (sliding)
- plates slide past each other
Example: San Andreas Fault
- causes earthquakes
° Earthquake
• What is an Earthquake?
- sudden shaking of the ground caused by movement along faults
Key terms:
• Focus (Hypocenter)
- where earthquake starts underground
• Epicenter
- point on the surface above focus.
• Fault
- crack in Earth's crust
Causes:
- Plate movement (most common)
- Volcanic activity
- Human activities (rare)
•Measuring Earthquake
Magnitude
- strength (measured using Richter scale)
Intensity
- how strong it feels
° Volcanoes
• What is a volcano ?
- opening in Earth's crust where magma, gas, and ash escape.
• Types of Volcanoes
1. Shield Volcano
- wide, gentle slopes
- quiet eruptions
Example: Mauna Loa
2. Composite Volcano (stratovolcano)
- tall, steep
- explosive eruptions
Example: Mount Fuji
3. Cinder cone
- small, steep
- built from ash and rocks
• Why volcanoes Form
- mostly at plate boundaries
- especially at convergent and divergent boundaries
- also at hotspots (e.g., Hawaii)
•How Everything Connects
-> Plate movement = earthquakes + volcanoes
Plate collide -> earthquakes + volcanoes
Plates separate -> volcanoes
Plates slide -> earthquakes
* That's why areas like the Pacific Ring of Fire have many earthquakes and volcanoes
STARS AND CONSTELLATIONS
• Stars
a massive, glowing ball of hot gas (mostly hydrogen and helium) that produces energy through nuclear fusion
• Key Features of Stars:
- produce their own light and heat
- made mostly of hydrogen gas
- powered by nuclear fusion
- Can vary in:
° Size (giants us dwarfs)
° Color (blue, white, yellow, red)
° Temperature
Blue stars = hottest
Red star = cooler
• How do stars form?
-Stars are born in huge clouds of gas and dust called nebulae
Basic Stages:
1. Gas and dust champ together
2. Gravity pulls them tighter
3. The core gets hotter
4. Nuclear fusion begins - a star is born.
• Life Cycle of a star (simple version)
□ Small stars (like the sun)
- Live long - becomes red giants -> end
as white dwarfs
□ Massive stars
- Live fast - explode as supernovae -> become neutron stars or black holes
° Constellation
- a group of stars that form a pattern in the sky, often named after:
□ animals
□ Objects
□ Mythological figures
•Famous Constellations
Ursa Major
- contains the big dipper
- helps locate the North star
Orion
- very easy to spot
- has three stars in a row (Orion's belt)
Scorpius
- looks like a curved scorpion
- visible in tropical regions like the Philippines
• Why are constellations important?
- people have used constellations for thousand of years:
□ Navigation (sailors used stars to find direction)
□ Calendar and seasons
□ Stories and myths
□ Astronomy (helps scientists map the sky)
• Fun Facts
- there are 88 officially recognized constellations
- the closest star after the Sun is Proxima Centauri
- some stars we see may already be "dead" - their light is just still travelling to us.
OTHER COMPONENTS OF SOLAR SYSTEM AND PLANETS CLASSIFICATION
Asteroid Belt
- region between Mars and Jupiter filled with asteroids
Kuiper Belt
- region beyond Neptune, containing many icy bodies and dwarf planets
Oort Cloud
- a spherical shell of icy objects surrounding the Solar System
PLANETS CLASSIFICATION
Terrestrial planets
- mercury, venus, earth, mars
- rocky surfaces, small
Gas Giants
- saturn, jupiter
- large and mostly composed of hydrogen and helium
Ice giants
- uranus, neptune
- composed of mostly heavier elements like water, ammonia, and methane.
Dwarf Planets
- Pluto, Eris, Haumea, Makemake, and Ceres
- smaller than the main
- planets and do not clear their orbits of other debris
STELLAR EUOLUTION AND GALAXIES
Stars form clouds of gas and dust (nebulae) and go through several stages:
1. Protostar
- contracting mass of gas that represents early stage of star formation.
2. Main sequence
- longest stage in a star's life, where it fuses hydrogen and helium
3. Red Giant / Supergiant
- a later stage where the star expands after exhausting hydrogen in its core.
4. Final stages: Depending on the mass
White Dwarf
- remnant of a low to medium mass star
Neutron star
- remnant of a high-mass star.
Black Hole
- result of the collapse of a very massive star.
SCIENCE GALAXIES
Galaxies are vast systems containing millions to billions of stars
• Types of Galaxies
1. Spiral Galaxies
- have a flat rotating dish with a central bulge and spirul arms (e.g.. Milky way)
2. Elliptical Galaxies
- range from spherical to elongated shapes, with little to no new star formation
3. Irregular Galaxies
- lack a distinct shape, often chaotic in appearance
TYPES OF ROCKS
Rocks
- naturally occuring solid materials made of minerals
Mineral
- inorganic, naturally occuring solid
- has definite chemical composition and atomic structure
Inorganic - not living, never was living
Naturally occuring - can't be man made
Mineral Characteristics
- Color (not the most reliable characteristic
- Hardness (can be identified using moscale of hardness)
- Luster (metallic, non-metallic)
- Streak (color of the mineral in its powdered form)
- Cleavage/Fracture (how a mineral breaks)
* Cleavage - breaks predictably
* Fracture - breaks randomly
- Other
° Classifications of Rocks:
1. Igneous rocks
- formed when molten rocks (magma or lava) cools and hardens.
- there are 17 in total
* Magma - molten rock inside Earth
* Lava - molten rock on the surface
- classified based on their texture (coarse-grained. fine-grained, glassy) and mineral composition (mafic, intermediate, felsic)
Types of igneous rocks:
a. Intrusive (plutonic)
- cools slowly under ground
- large crystals
Example: granite
1-10 mm Coarse: example is granite
10 mm or larger: example is pegmatite
Felsic - rich in silicon and aluminum
Mafic - rich in iron and magnesium
b. Extrusive (volcanic)
- cool quickly on the surface
- small or no crystal
Example: Basalt, obsidian
- not able to grow very large at all
- usually have fine texture
Fine/less than 1mm: Basalt, Rhyolite
Glassy (non-crystalline): obsidian, pumice
-cooled so quickly that crystalls are impossible to see
Vesicular (gas pockets)
- cooled quickly enough for little air bubbles to be trapped inside
- example is pumice
Key Features:
□ No layers
□ Very hard
□ No fossils
2. Sedimentary Rocky (from sediments)
- sedimentary rocks are formed from small particles (sediments) like sand, mud, or shells that are compressed and cemented over time.
- formed by transportation and deposition of sediments by water, wind, or ice
Types:
a. Clastic
- made from broken rock picces
Ex: sandstone
b. Chemical
- formed from minerals left behind by evaporated water
Ex: rock salt
c. Organic
- formed from remains of plants and animals
Ex: Coal
Key Feature
-Usually have layers (stata)
- often contain fossils
- Can be soft
3. Metamorphic rocks (changed rocks)
- formed when existing rocks are changed by heat and pressure (but don't melt)
- Development of new mineral assemblages and textures, such as follation or banding
Types:
a. Foliated
- have layers or bands
Ex: slate, marble (some forms)
- formed primarily from regional metamorphism
*Regional metaphormism
- heat and pressure increases
- primarily result of pressure
*Mineral alignment
- minerals line up as a result of intense pressure
*Banding
- severe version of mineral alignment.
- minerals seperate into dark and light stripe called bands
b. Non-foliated
- no visible layers
Ex: Quartzite
Key Features:
- hard and dense
- may have shiny or wavy patterns
- form deep underground
° The rock cycle
- all rocks are connected through the rock cycle
• Igneous -> weathering -> Sedimentary
• Sedimentary - heat and pressure ->
metamorphic
• Metamorphic - melting -> Igneous
* Rocks are constantly changing over years
LAYERS OF THE ATMOSPHERE
Earth's Atmosphere
- blanket of gases surrounding Earth
- protects us from harmful solar radiation, provides breathable air and helps regulate temperature
• Composition of the atmosphere
Nitrogen (N2):78%
Oxygen (O2): 21%
Argon (Ar) 0.93%
Carbon Dioxide (CO2): 0.04%
Trace Gases: includes neon, helium, methane, krypton, and hydrogen.
Water Vapor: varies from 0 to 4% depending on the region and weather conditions
• Structure of the atmosphere
1. Troposphere (clasest to Earth)
Altitude: 0 to 12 km
Key Features:
-This is where we live
- all weather happens here (rain, clouds, storms)
- contains about 75% of the atmosphere's mass
- temperature decreases as you go up.
Fact: Airplanes usually fly near the top of this layer to avoid turbulance
2. Stratosphere
Altitude: 12 to 50 km
Key features:
- contains the ozone layer, which absorbs harmful UV radiation
- temperature increases with altitude (because ozone absorbs heat)
- air is more stable—less turbulence
• Why it matters:
- Without this layer, life on Earth would be exposed to dangerous radiation
3. Mesosphere
Altitude: 50 to 85 km
Key Features:
- the coldest layer (can reach -90°c)
- meteors burn up here
- temberature decreases with altitude
Fun Fact: when you see a shooting star, it's actually a meteor burning in this layer
4. Thermosphere
Altitude: 85 to 600 km
Key Features:
- temperature increases dramatically
(can exceed 1,500 °C)
- can contain the ionosphere, important for radio communication
- home to auroras (northern and southern lights)
Facts: The International Space Station orbits in this layer.
5. Exosphere (outermost layer)
Altitude: 600 km and above
Key Feature:
- thinnest layer
- gradually fades to outer space
- contains very few gas particles
Fact: Some satellites orbit in this region.
• Easy Way to Remember
- "The Smart Monkey Took Exams"
• Why the atmosphere is important
- provides oxygen for breathing
- protects us from meteors and radiation
- regulates temperature
- makes weather and climate possible
WEATHER
Weather
- the state of the atmosphere at specific time and place
- influenced by various factors such as temperature, humidity, precipitation, wind, and visibility.
° Key Elements of Weather
1. Temperature
- how hot or cold the air is
- measured with a thermometer (°C or °F)
2. Humidity
- the amount of water vapor in the air
- "High humidity" = feels sticky and sweaty
3. Wind
- moving air
- caused by differences in air pressure
measured by speed (anemometer) and
direction (wind vane)
4. Clouds
- made of tiny water droplets or ice crystals
• Types include:
Cumulus - fluffy, fair weather
Stratus - gray cloudy skies
Cirrus - thin, high clouds
Nimbus - rain clouds
5. Precipitation
- water falling from the sky: rain, snow, hail
- happens when clouds get too heavy
6. Air Pressure
- the weight of air pressing down on Earth
- measured using barometer.
- high pressure = good weather
low pressure = storms
° What Causes Weather?
- weather happens because of energy from the Sun
Main factors:
- uneven heating of Earth
- movement of air (wind)
- water cycle (evaporation → condensation → precipitation)
-> These processes are part of atmospheric circulation, which moves heat around the planet
o Types of Weather
- Sunny
- cloudy
- ralny
- stormy
- windy
° Weather Patterns and Phenomena
• Air Masses
- large bodies of air with uniform temperature and humidity.
-influence regional weather
• Front
-boundaries between different air masses
• Cold Front
- cold air displaces warm air, often leading to thunderstorms
• Warm Front
- warm air displaces cold air leading to
prolonged penods of cloudiness and
precipitation.
• Occluded Front
-when a cold front overtakes a warm front
• High and Low Pressure Systems
- High Pressure System associates with fair weather
- Low-Pressure System associated with stormy weather
• Cyclones and anticyclone
- cyclone system of winds rotating inward to an area of low pressure, often resulting in storms
- anticyclone: system of winds rotating outward from an area of high pressure, usually bringing clear skies.
° Severe Weather
Thunderstorms
- caused by rapid upward movement of warm, moist air
Tornadoes
- violently rotating columns of air extending from a thunderstorm to the ground
Hurricanes
-large, powerful storms forming over warm ocean waters with strong winds and heavy rain
Blizzards
-severe snowstorms with strong winds and low visibility
Heatwaves
-prolonged periods of excessively hot weather
° Climate vs Weather
Weather
-short-term atmosphere conditions at a specific place and time
Climate
- long term average of weather
patterns over a significant period
(usually 30 years or more)
° Factors influencing Climate
1. Latitude
-affects the angle and intensity of
solar radiation
Elevation
- higher elevation have cooler temperature
3.Ocean Currents
- distribute heat around the globe
4. Topography
-mountains can block air movement
and precipitation patterns.
5. Vegetation
- influence heat absorption and
moisture retention.
Weather Instruments
- tools used by scientists (called meteorologists) to measure different parts of the atmosphere
-help us understand and predict weather
• Different Weather Instruments
1. Thermometer
- measures temperature
Measures: how hot or cold the air is
Unit: Degrees Celcius (°C) or Fahrenheit (°F)
How it works: A liquid (usually mercury or alcohol) expands when heated and rises in a tube.
Example: A reading of 30°C means it's hot
2. Anemometer
-measures wind speed
Measures: How fast the wind is blowing
Unit: km/h or m/s
How it works: Cups attached to arms spin when wind blows - faster they spin, the stronger
3. Wind Vane
-measures wind direction
Shows: where the wind is coming from
How it as works: an arrow spins and points toward the direction the wind originates.
Example: If it points north the wind is coming from the north
4. Rain Gauge
- measuns rainfall
Measures: amount of rain
Unit: millimeters (mm)
How it works: rain collects in a container, and the depth is measured
Example: 10 mm: light rain; 50 mm = heavy rain
5. Barometer
- measures air pressure
Measures: atmospheric pressure
Unit: millibars (mb) or hectopascals (hPa)
How it works: It detects changes in air pressure
Key Idea:
• High pressure - usually fair weather
• Low pressure - often stormy weather
This relates to the scientific concept of
atmosphene Pressure
6. Hygrometer
- measure humidity
Measures: amount of water vapor in the air
Unit: percentage (%)
How it works: Detect moisture levels in the air
Example: 30 % = dry; 90% = very humid
7. Pyranometer
- measures solar radiation
Measures: sunlight energy reaching Earth
Why it matters: helps in studying climate and solar power
° Why are weather instruments important
They help us:
Predict storms and typhoons
-Prepare for disasters
- plan daily activities (like farming or travel)
- study climate and environmental changes
-> Meteorologists use these tools together to understand the full pictures of the weather system