This document provides an overview of earth science topics including the branches of earth science like geology, meteorology, oceanography, and paleontology. It discusses instruments used to study the earth like microscopes, the Richter scale, and the Mercalli scale. It also covers scientific methods, measurement systems, astronomy concepts, and components of the universe like galaxies, stars, and solar systems.

1. EARTH SCIENCE LECTURE COMPILATION
Christopher D. Balubayan
Instructor
Earth Science- is the study of the planet earth as a whole
-it scope are: mining and extraction of minerals and gems; prediction
of weather and earthquakes, pollution of the atmosphere, and the
forces that shape the physical world.
Branches of Earth science
1. Geology- study of the earth, its origin, composition, structure, and history
Different branches: a) Mineralogy (minerals of the earth), b) Petrology
(rocks), c) Stratigraphy (disposition of successive beds of sedimentary
rocks), d) Palaeontology (fossils), e) Tectonics ( deformation and
movement of the earth’s crust), f) Geophysics ( using physics to study
the earth’s surface, interior, and atmosphere), g) Geochemistry
(science of chemistry as it applies to biology).
2. Meteorology- scientific observation and study of the atmosphere, so that
weather can be accurately forecast.
3. Oceanography- involves the study of water movements, current, waves, and
tides, and the chemical and physical properties of the seawater.
4. Geochemistry- deals with the relative and absolute abundances of the
chemical elements and their isotopes in the earth, and also the
chemical changes that accompany geologic processes.
5. Palaeontology- the study of ancient life, encompassing the structure of
ancient organisms and their environment, evolution, and ecology, as revealed
by their fossils and the rocks those fossils are found in.
Instruments Used to Study the Earth
1. Microscope- instrument for forming magnified images with high resolution for
detail
a. Optical Microscope- usually has two sets of glass lenses and an
eyepiece. It was invented 1609 in the Netherlands by Zacharias
Janssen (1580-1638).
b. Transmission Electron Microscope- was developed from 1932 passes
a beam of electrons, instead of a beam of light, throuh a specimen.
Since electrons are not visible, the eyepiece is replaced with a
fluorescent screen or photographic plate; far higher magnification and
resolution are possible than with the optical microscope.
c. Scanning Electron Microscope- it was developed in the mid-1960s
and moves a fine beam of electrons over the surface of a specimen,
the reflected electrons being collected to form the image. The
specimen has to be in a vacuum chamber.
d. Acoustic Microscope- it passes an ultrasonic (ultrahigh-frequency
sound) wave through the specimen, the transmitted sound being used
to form an image on a computer screen.
e. Scanned-Probe Microscope- it was developed in the late 1980s and
runs a probe, with a tip so fine that it may consists only of a single
atom, across surface of the specimen.
f. Scanning Tunnelling Microscope- an electric current that flows
through the probe is used to construct an image of the specimen. In
1988 a scanning tunnelling microscope was used to photograph a
single protein molecule for the first time.
g. Atomic Force Micros cope- the force felt by the probe is measured
and used to form the image. These instruments cam magnify a million
times and give images of single atoms.
2. Richter Scale- a quantitative scale of earthquake magnitude based on
measurement of seismic waves, used to indicate the magnitude of an
earthquake at its epicentre. The magnitude of an earthquake differs
from its intensity, measured by the Mercalli Scale, which is qualitative
and varies from place to place for the same earthquake. The scale
named after US seismologist Charles Richter.
3. Mercalli Scale- a qualitative scale of the intensity of an earthquake. It differs
from the Richter Scale, which indicates earthquake magnitude and is
quantitative. It is named after the Italian seismologist Giuseppe
Mercalli (1850-1914).
Modified Mercalli Scale
Intensity
Value
Description
I Not felt except by a very few under especially favourable

2. conditions
II Felt only by a few persons at rest, especially on upper floors of
buildings
III Felt quite noticeable by persons indoors, especially on upper floors
of buildings, many people do not recognize it as an earthquake;
standing motor cars may rock slightly
IV Felt indoors by many, outdoors by a few persons during the day; at
night, some awakened; dishes, windows, doors disturbed; walls
make cracking sound; standing motor cars rock noticeably
V Felt by nearly everyone; many awakened; some dishes, windows
broken; unstable objects overturned; pendulum clocks may stop
VI Felt by all; some heavy furniture moved; a few instances of fallen
plaster; damage slight
VII Damage negligible in buildings of good design and construction;
slight to moderate in well-built ordinary structures; considerable
damage in poorly built or badly designed structures; some
chimneys broken
VIII Damage slight in specially designed structures; considerable
damage in ordinary substantial buildings with partial collapse;
damage create in poorly built structures; fall of chimneys factory
stacks, columns, monuments, walls, heavy furniture overturned
IX Damage considerable in specially designed structures; damage
great in substantial buildings with partial collapse buildings shifted
off foundations
X Some well built wooden structures destroyed; most masonry and
frame structures with foundations destroyed; rails bent
XI Few, if any (masonry) structures remain standing; bridges
destroyed; rails bent greatly
XII Damage total; lines of sight and level are distorted; objects thrown
into the air
Pattern of a Scientific Method
1. Defining Problems- an activity usually begins with a problem that needs
solution. The problems should be identified as specially as possible.
2. Observation- these are concise statements that need to be recorded
immediately and clearly indicate what you have observed.
3. Measurement- this is the formulation and application of mathematical
statement that relates the observations.
4. Experimentations- the actual testing following the tentative procedure.
5. Making Hypotheses- construction of tentative answer to the problems that are
mentally formulated conforming to the observed law.
6. Developing Theories- tentative explanations obtained from observations and
have been likewise melded and modified by testing.
Law versus Theory
Law
1. It correlates a series of observations.
2. It is essentially empirical.
3. It records and summarizes in a concise.
4. From the results of numerous experiments.
5. It is directly observable.
Theory
1. It explains observations in terms of what is imagined.
2. It predicts what has yet been observed.
3. It remains tentative until it becomes directly observable.
4. Not directly observable.
Scientific Model-a complete picture or pattern you construct to explain or answer
your question. This model may be an idea of the way something is, or it may
be a physical construction that is similar in form to something.
Characteristics of a Scientific Method
1. It is changeable
2. It is observable
3. It is doable
4. It is proportion to the real situation
The Laboratory
A place equipped for scientific study and testing. But for earth scientists, all
the earth and all that surround them may be called as laboratory.
Laboratory Safety procedures
Safety is one of the most important words that a student should observe. The
following are the safety guidelines that need to be followed during
experimentation though most of the experiments you will do are quite safe.
1. Before performing the first experiment, make sure that you have already
familiarized the locations of the following; fire extinguisher, safety showers, eye
washers, fine blankets, first aid cabinet, and other safety equipment in the lab.
2. Read the instructions before doing the required experiment.
3. Follow exactly all written directions unless your instructor gives you other
directions.
4. Read all labels before using a chemical.
5. Work in an organized manner. There should be no fooling around, pushing or
running.

3. 6. Spills, accidents or injuries should be reported to your instructor immediately.
7. Use only tongs, test tube holders or potholders to hold hot glassware’s.
8. Make sure that your working place is dry and free from flammable materials.
9. Do not use any electrical equipment with frayed cords, loose connections, or
exposed wires. Report such equipment to your instructor.
10. At the end of every activity, clean up your work area, put everything away and
wash your hands.
Measurement
One of the big ideas behind science is the idea of studying things to see how
they change. But to find out how things change, you need to measure those
things first. This is why every scientist needs to be able to measure things,
and why scientists need to be able to understand each other’s
measurements.
Systems of Measurement
1. Metric System
It is accepted worldwide because of its convenience (power of notation). It
was originally described as MKS (meter-kilogram-second) and later
recognized to SI or International System in 1960.
Metric Units
Quantity Units Symbols
Length Meter m
Mass Kilogram k
Time Second s
Electric Current Ampere A
Temperature Kelvin K
Amount of
Substance
Mole mol
Luminous Intensity Candela cd
2. English System
It is commonly used in English-speaking countries that are also known as
British System.
Astronomy- The science of the celestial bodies; the sun, the moon, and the planets;
the stars and galaxies; and all other objects in the universe. It is concerned
with their positions, motions, distances, and physical conditions and their
origins and evolution.
Divisions of Astronomy
1. Astrophysics
2. Celestial Mechanics
3. Cosmology
Telescope- is an optical instrument that magnifies images of faint and distant objects;
any device for collecting and focussing light and other forms of
electromagnetic radiation.
Types of Telescope
1. Refracting Telescope- the light is collected by a lens called the object glass or
objective, which focuses light down a tube, forming an image
magnified by an eyepiece.
2. Reflecting Telescope- light is collected and focused by a concave mirror.
Spectral Classification- classification of stars according to their surface temperature
and luminosity, as determined from their spectra.
Spectroscopy- study spectra associated with atoms or molecules in solid, liquid, or
gaseous phase. It can be used to identify unknown compounds and is an
invaluable tool in science, medicine, and industry.
a. Emission Spectroscopy- deals with the characteristic series of sharp lines in
the spectrum produced when an element is heated.
b. Absorption Spectroscopy- deals with atoms and molecules as they absorb
energy in a characteristic way.
c. Infrared Spectroscopy- concerned with molecular vibrations, or nuclear
magnetic resonance (NMR).
d. Supersonic Jet Laser Beam Spectroscopy- enables the isolation and study of
clusters in the gas phase. A laser vaporizes a small sample, which is
cooled in helium, and ejected into an evacuated chamber.
Types of Spectra
1. Continuous Spectrum- dispersed radiation i s distributed uninterruptedly over
a
range of wavelengths.
2. Line Spectrum- a gaseous element gives one or more bright discrete lines at
a characteristic wavelengths.
3. Absorption Spectrum- dark lines or spaces replace the characteristic bright
lines of the absorbing medium.
4. Mass Spectrum- an element is obtained from a mass spectrometer and
shows the relative proportions of its constituent isotopes.
Electromagnetic Waves- a type of wave showing the oscillation of electric and
magnetic fields travelling together through space at a speed of nearly
300,000 km per second.
Classification of Electromagnetic Waves
1. Radio and Television Waves
2. Infrared Radiation
3. Visible Light
4. Ultraviolet Radiation
5. X-Rays Radiation

4. 6. Gamma Ray radiation
Universe
All existing matter and space considered as a whole; the cosmos. The
universe is believed to be at least 10 billion light years in diameter and
contains a vast number of galaxies. It has been expanding since its creation
in the Big Bang about 13 billion years ago.
Galaxy
A system of millions or billions of stars, together with gas and dust, held
together by gravitational attraction. It is about 100,000 light years in diameter,
and contains at least 100 billion stars. It is a member of a small cluster, the
Local Group. The sun lies in one of its spiral arms 25,000 light years from the
center.
Characterise of Galaxy
1. Galaxies vary in size, structure, and luminosity.
2. Like stars, they are found alone, in pairs, or in clusters.
3. As these systems are very remote, they appear in telescopes as hazy,
nebulous objects and were first described as nebulae.
4. Later when their remoteness was understood, they were known as “island
universes” or “extra-galactic nebulae
Types of Galaxy
1. Elliptical Galaxy
a) Has shaped like a spheroid, or elongated sphere.
b) In the sky, where we can only see two of their three dimensions, these
galaxies look like elliptical, or oval, shaped disks.
c) The light is smooth, with the surface brightness decreasing as you go
farther out from the center.
d) It has given a classification that corresponds to their elongation from a
perfect circle, otherwise known as their elasticity.
e) The larger the number, the more elliptical the galaxy is.
f) So, for example a galaxy of classification of E0 appears to be perfectly
circular, while a classification of E7 is much flattened.
g) The elliptical scale varies from E0 to E7.
h) Elliptical galaxies have no particular axis of rotation.
2. Spiral Galaxy
• Have 3hree Main Components:
a. The Bulge
• Is a spherical structure found in the center of the galaxy this
feature mostly contains older stars.
b. The Disk
• Is made up of dust, gas, and younger stars.
• It forms arm structures.
• Our Sun is located in an arm of our galaxy, the Milky Way.
c. The Halo
• Is a loose, spherical structure located around the bulge and
some of the disk? It contains old clusters of stars, known
as”globular clusters”.
• Spiral Galaxies are Classified into Two Groups
a. The Ordinary Group
• The arms originate directly from the nucleus, or bulge.
b. The Barred Group
• There is a bar of material that runs through the nucleus that
the arms emerge from.
Both of these types are given a classification according to how tightly their arms are
wound. The classifications are; a, b, c, d ... with "a" having the tightest arms. In type
"a", the arms are usually not well defined and form almost a circular pattern.
3. SO Galaxy
a. S0 galaxies are an intermediate type of galaxy between E7 and a "true"
spiral SA.
b. They differ from elliptical because they have a bulge and a thin disk, but
are different from SA because they have no spiral structure.
S0 galaxies are also known as”Lenticular galaxies”.
4. Irregular Galaxy
 Have no regular or symmetrical structure.
• They are divided into two groups,
1. Irr I Type Galaxies
– Have HII regions, which are regions of elemental
hydrogen gas, and many Population I stars, which are
young hot stars.
2. Irr II Type Galaxies
– Simply seem to have large amounts of dust that block
most of the light from the stars.
– All this dust makes is almost impossible to see distinct
stars in the galaxy.
Milky Way
o Is the galaxy that contains our Solar System.
o Its name “milky” is derived from its appearance as a dim glowing band
arching across the night sky in which the naked eye cannot
distinguish individual stars.
o The term “Milky Way” is a translation of the Latin via lactea, from
the Greek “galaxías kýklos”, "milky circle").
o From the Earth, the Milky Way appears as a band because its disk-
shaped structure is viewed from within the Galaxy.
o Galileo Galilei first resolved the band of light into individual stars with
his telescope in 1610.

5. o Up until the early 1920s, most astronomers thought that all of the
stars in the universe were contained inside of the Milky Way.
o Following the 1920 Great Debate between the astronomers Harlow
Shapley and Heber Curtis, observations by Edwin Hubble definitively
showed that the Milky Way is just one of many billions of galaxies.
Solar System
• The collection of eight planets and their moons in orbit around the sun,
together with smaller bodies in the form of asteroids, meteoroids, and
comets.
• Regardless of your view, here's the order of the eight larger planets, starting
nearest the sun and working outward through the solar system: Mercury,
Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
Stars- are luminous globe of gas, mainly hydrogen and helium, which produces its
own heat and light by nuclear reactions. Although stars shine for very long
time, many billion years, they are not eternal, and have been found to change
in appearance at different stages in their lives.
The smallest mass possible for a star is about 8% that of the sun (80 times
that of Jupiter), otherwise nuclear reactions do not occur. Objects with less
than this critical mass shine only dimly, and are termed brown dwarfs.
Origin- stars born when nebulae (giant clouds of dust and gas) contract under the
influence of gravity.
Type of Stars
1. Main Sequence Stars-when energy produced in the nuclear reaction can
replace that being lost at the surface, likewise, the star has no need to
contract further until its nuclear energy sources are exhausted.
2. Giants- the second type of star lies above and to the right of the main
sequence band. Furthermore, it is brighter than the main sequence
star.
3. Supergiant- is the largest and most luminous type of star known, with a
diameter of up to 1,000 times that of the sun and apparent magnitude
of between 0.4 and 1.3.
4. White Dwarfs- a star may called as this if it is less than 1.2 that of the sun,
and is outer layer drift off into space to form a planetary nebula, and
its core collapses in on itself to form a small and very dense.
Cluster Star-stars formed together at same time stars may be gravitationally bound
together two types: open (galactic) and globular
1. Open Cluster or Galactic- dozens to thousands of stars young stars! only a
few million years old may still be surrounded by nebula from which they
formed located in the spiral arms of a galaxy; example: Pleiades.
2. Globular Cluster- millions to hundreds of millions of stars old! 6 to 13 billion
years mostly red giants and dwarfs stars are clumped closely
together, especially near the center of the cluster (densely) surround
our disk as a halo.
Nebula- A cloud in space. Made of gas and dust, and have stars inside, most of the
ones we see are inside our Milky Way Galaxy and has different types; a0
Emission Nebula (The hot gas is emitting light); b) Colder-darker Nebula
(Dark dust blocking the hot gas behind it); c) Supernova remnant
(smaller, less gas)
Light Year- A light year is the distance light travels in a year. Light moves at a
velocity of about 300,000 kilometres (km) each second; how far would it
move in a year? About 10 trillion km (or about 6 trillion miles).
Parallax- Sine of an angle x Earth’s distance to the Sun = Distance to the star