General Science Notes

SCIENCE

General Science

LESSON 1: SCIENCE

• Science is a systematized body of knowledge acquired through research.

1.1. BRANCHES OF SCIENCE

• a. Physical Sciences: Study of nature and properties of the universe and its contents.
  • Astronomy
  • Meteorology
  • Chemistry
  • Physics
  • Geology
• b. Biological Sciences: Study of living organisms and life itself.
  • Botany
  • Zoology
• c. Social Sciences: Study of humans as individuals, human society, and human interactions.
  • Psychology
  • Sociology

LESSON 2: SCIENTIFIC METHOD

• Scientific Method is the systematic method of acquiring knowledge.

2.1. STEPS OF THE SCIENTIFIC METHOD

• i. Making Observations: Make an observation using one’s senses.
• ii. Stating the Problem:
  • Must be clear and specific.
  • Must be measurable and have an attainable solution.
  • Usually stated in question form.
• iii. Forming the Hypothesis:
  • Hypothesis is a tentative solution to a problem or a prediction of the outcome.
  • Must be a clear and specific statement.
• iv. Testing the Hypothesis:
  • Implement the hypothesis under carefully considered conditions.
  • Control and experimental setups must be used for comparison of results.
  • Collect all necessary information related to the problem that may help you achieve your goal.
• Types of variables
  • Independent: Factors that are NOT affected by other variables; usually predetermined.
  • Dependent variables: Factors that are affected by other variables.
  • Controlled variables: Factors that are kept the SAME for all setups.
  • Manipulated variable: Factor that is DIFFERENT in each set-up; usually the variable under study.
• v. Conclusion:
  • Results must be analyzed for validity.
  • Final answer to the problem.
  • Should always be true based on the analysis.

2.2. KINDS OF REASONING

• a. Inductive Reasoning: A conclusion is made based on REPEATED OBSERVATION; basis of most experimental conclusions; specific to general.
• b. Deductive Reasoning: A conclusion is made based on established PRINCIPLES and CONCEPTS; basis of most research conclusions; general to specific.

LESSON 3: MEASUREMENTS AND QUANTITIES

3.1. SIGNIFICANT FIGURES

• Digits in a number that are considered important.
• RULES ON DETERMINING SIGNIFICANT FIGURES:
  • All nonzero digits are significant.
  • Final zeros in the decimal place are significant.
  • All zeroes in between significant figures are significant.
  • Place holders are zeros that are NOT considered significant.

3.2. SCIENTIFIC NOTATION

• A shorthand representation of numbers using powers of 10.
• STANDARD TO SCIENTIFIC
  1. Move the decimal point to obtain a number less than 10 but greater than or equal to 1.
  2. Write “x 10” after the number.
  3. Count the number of places that the decimal point was moved starting from its original position and use the number as the power of 10 (exponent).
  4. If the decimal point was moved to the left, the exponent is positive. Otherwise, it is negative.
• $a \times 10^b$
  • where:
    • $a$ is a number less than 10 but greater than or equal to 1
    • $b$ is an exponent

3.3. ROUNDING OFF

• Method of reducing the digits in a number while keeping its value similar. RULES ON ROUNDING OFF:
  • If the digit prior (digit with lower place value) to the digit to be rounded off is:
    1. less than 5, RETAIN value and replace whole numbers on the right with zero
    2. greater than or equal to 5, ADD 1 to the digit being rounded off and replace all digits on its right with zero

3.4. EQUATIONS

• Representation of the relationship between quantities.
  • a. DIRECT RELATIONSHIP: Variables A and X changes with the same proportion.
  • b. INVERSE RELATIONSHIP: Variables B and X changes with the opposite proportion.
  • c. POWER: Variable X changes in the same proportion as C but raised to the power n.
  • d. INVERSE POWER: Variable X changes with the inverse proportion as D but raised to the power m.

3.5. FUNDAMENTAL QUANTITIES

• Fundamental Quantities are physical quantities that can be determined by using measuring devices.

• Derived Quantities are physical quantities that can be determined by calculating fundamental quantities.

3.6. UNITS OF MEASUREMENTS

• Measurement is a standard unit to express the size, amount, or degree of something.
• Systems of Measurement:
  • a. English System: Evolved from the medieval systems of measurements; ex. foot, pound, Rankine
  • b. Metric System: Based on multiples of 10 (except for time); ex. meter, gram, second, Kelvin

3.7. CONVERSION OF UNITS

• In converting units, in order to get the desired measurement, we simply multiply the given measurement by a conversion factor, which is a ratio of two measurements with different units that is equal to 1.

• $\frac{Original \space value}{given \space unit} \times \frac{desired \space unit}{Equivalent \space value}$

• Other Units of Measure:

  • Celsius and Fahrenheit — units of temperature that are used in different measuring devices and have different scales
  • $Celsius \space + 32 = Fahrenheit$

• Prefixes Used with Units

EARTH SCIENCE

LESSON 1: GEOLOGY

• Geology is the study of the Earth’s structure, history, and processes involved in it.
• Parts of the Earth:
  • Geosphere
  • Hydrosphere
  • Atmosphere

1.1. GEOSPHERE

A. LAYERS OF THE EARTH

• i. Crust - outermost layer of the Earth; up to 100 km below sea level.
  • Continental Crust (sial) — portion of the crust not covered by the ocean
  • Oceanic Crust (sima) — portion of the crust under the ocean
• Transition Zone:
  • Lithosphere — region made of solid rocks; includes the crust and the upper solid part of the mantle.
  • Asthenosphere — region made of semi-solid rocks; portion where rocks begin to melt; divided into a soft upper layer and a hard lower layer.
• ii. Mantle - layer of the Earth under the crust to 2900 km into the center; made mostly of molten rocks.
• iii. Outer Core - made mostly of molten elements, mostly iron and nickel.
• iv. Inner Core - made of solid light elements like iron and nickel.

B. TECTONIC PLATES

• Tectonic Plates — rigid pieces of the Earth’s crust and upper mantle
• Plate Tectonics — a scientific theory that describes the large-scale motions of the Earth’s lithosphere
• Continental Drift Theory
  • Theorizes that the Earth had a single continent through most of geologic time.
  • Evidence: jigsaw-like fit of continental boundaries and similarities between coastal rock formations between facing continental coasts
  • Pangea is the singular super continent while Panthalassa is the vast ocean surrounding it.
• Sea-floor Spreading
  • The process in which the ocean floor is extended when two plates move apart.

Plate Boundaries

• i. Divergent Boundary
  • Plates MOVE AWAY from each other
  • Constructive (new crust is created)
  • Can cause formation of ridges (ex. Mid-Atlantic Ridge)
• ii. Convergent Boundary
  • Plates MOVE TOWARDS each other
  • Destructive (crust is destroyed as they submerge)
  • Types
    • oceanic-continental — forms trenches
    • oceanic-oceanic — forms trenches
    • continental-continental — forms mountains ranges, volcanoes
• iii. Transform Boundary
  • Plates MOVE ALONG OR SLIDE PAST EACH OTHER
  • Conservative (crust is neither created nor destroyed).

C. EARTHQUAKE

• Earthquakes are shaking of the ground caused by the release of tension built up in the plate boundaries
• PARTS OF AN EARTHQUAKE
  • Focus — point beneath the Earth’s surface where rocks break under stress and the plates shift causing an earthquake,
  • Epicenter — center of the quake on the surface directly above the focus.
  • Body Waves — seismic/energy waves that travel underground from the focus to the surface.
    • Primary or P waves — compressional; fast and can travel through all mediums; particles move in the direction of the wave.
    • Secondary or S waves — shear; slower than P waves and can only travel through solid rock; particles move perpendicular to the direction of the wave
    • P waves are longitudinal waves
  • Surface Waves — seismic waves that travel along the surface of the earth; slower than body waves.
    • Rayleigh — “ground roll”; dissipates as it travels farther from the center
    • Love — sideways movement that occurs when the ground is composed of multiple layers.
• Tsunami — series of enormous waves caused by the sudden displacement of water, usually in oceans or large lakes; sudden upward movement of trenches cause most tsunamis.
• Richter Scale — the numerical scale for expressing the magnitude of an earthquake on the basis of seismograph oscillations; has the same value for an earthquake despite the location of the reading
• Mercalli Scale — uses the observations of the people who experienced the earthquake; not considered as scientific as the Richter Scale

D. ROCKS AND MINERALS

• Volcano is an opening or rupture in the Earth’s surface or crust where hot gases, lava, and rock fragments are released from the magma chamber below the surface
• PRINCIPAL TYPES OF VOLCANOES
  • Cinder cones
    • They are built from particles and blobs of congealed lava ejected from a single vent. As the gas-charged lava is blown violently into the air, it breaks into small fragments that solidify and fall as cinders around the vent to form a circular or aval cone.
    • The order of events: (1) eruption (2) formation of cone and crater; and (3) lava flow
  • Composite volcanoes (Stratovolcanoes)
    • They are typically steep-sided, symmetrical cones of large dimension built of alternating layers of lava flows, volcanic ash, cinders, blocks, and bombs and may rise as much as 8,000 feet above their bases
    • A conduit system through which magma from a reservoir deep in the Earth's crust rises to the surface and is built up by the accumulation of material erupted through the conduit and increases in size as lava, cinders, ash, etc., are added to its slopes
  • Shield volcanoes
    • They are built almost entirely of fluid lava flows
• Types of Rocks:
  • i. Igneous — formed when magma or lava solidifies
    • Intrusive - crystallizes below the Earth’s surface; cools slowly thus larger crystals are formed
    • Extrusive — erupt onto the surface; cools quickly thus form an amorphous glass
  • ii. Sedimentary — from rock residues that accumulates over time and hardens.
    • Clastic — from mechanical weathering debris
    • Chemical - formed when dissolved materials precipitate from solution
    • Organic — form from accumulation of plant or animal debris
  • iii. Metamorphic — rocks that undergo physical and chemical changes due to intense pressure and temperature.
  • The Rock Cycle
• Minerals — naturally occurring inorganic solids; defined by its specific chemical composition but it is easier to identify them in combination with their physical properties, as enumerated below.
  • Composition
  • Density
  • Hardness
  • Crystalline Structure
  • Color
  • Cleavage
  • Streak
  • Luster
  • Hardness -the ability of a mineral to resist being scratched; a relative hardness scale was developed based on the scratch test, where 1 is the softest and 10 is the hardest
• Mohs Scale of Hardness
  • 1-Talc
  • 6 — Feldspar
  • 2—Gypsum
  • 7 — Quartz
  • 3 — Calcite
  • 8 — Topaz
  • 4—Fluorite
  • 9 —Corundum
  • 5 — Apatite
  • 10 — Diamond
• Color —the most obvious property but the least diagnostic
• Streak — color of a mineral in its powdered form; shows the true color of the mineral
• Density — relates to the mineral’s composition and the pattern in which the mineral’s atoms are arranged
• Crystalline structure — minerals occur in shapes determined by the arrangement of their atoms, molecules, or ions
• Cleavage — tendency of a mineral to break along a plane
• Luster — the way a mineral reflects light
• Soil — fine fragments brought about by weathering that make up the ground; composed of mineral fragments, organic matter, water, and air.
• Erosion — term used to refer to the transfer of ground materials to another location; can be caused by natural or man-made events.
• Angle of repose — The steepest slope of the unconfined material on which the material can be heaped without collapsing; smooth and rounded grains have a low angle of repose while fine and sticky materials have a high angle of repose
• Slope angle less then the angle of repose: slope remains stable
• Slope angle greater than the angle off repose: mass wasting will occur

1.2. HYDROSPHERE

• Ninety seven percent (97%) of all the water on Earth is oceanic water
• The remaining 3% is freshwater; 2/3 of the freshwater is frozen in glaciers and ice caps; the rest are found underground, and only a small portion is found on the surface or in the atmosphere
• Oceanic Water
  • Covers 70% of the Earth’s surface
  • Composed of 96.5% water while the rest are dissolved gases and minerals
  • Surface currents are guided by wind and land formations
  • Deep ocean currents are guided by differences in water density, temperature, and depth
• Ground Water
  • Water that seeps underground through permeable rocks and accumulates differently at different depths.
• Zone of Saturation - region where water is always present.
• Water Table - region above the zone of saturation where water level changes depending on environmental conditions.
• Unsaturated Zone - region above the water table where water only passes through but not accumulate.
• Water Cycle
  • Evaporation — heat from the sun evaporates water from oceans, lakes, moist soil, leaves, and bodies of animals and humans.
  • Condensation — water molecules liquify and cling to dust particles in the high air to form clouds.
  • Precipitation — when moisture accumulating in the air becomes too heavy, they fall back to the earth; can be in the form of rain, snow, or hail.

1.3. ATMOSPHERE

• Atmosphere is made up of layers of gases enveloping the Earth. It is composed mostly of nitrogen (78%), oxygen (21%), and other gases.
• Importance:
  • Essential to the shaping of a planet
  • Its variables determine the climate and weather of the Earth
  • Protects the Earth from radiation from the Sun
  • Protects the Earth from various terrestrial materials such as meteors
• Layers of the Atmosphere

LESSON 2: METEOROLOGY

2.1. WEATHER

• Average atmospheric condition at a certain place at a given time.
• Atmospheric Variables: temperature, air pressure, moisture, and wind.
  • WEATHER DISTURBANCES
    • a. Wind Movement — hot air is less dense than cold air thus hot air rises and cold air sinks.
      • Sea breeze — takes place during the day; air flows from sea to land
      • Land breeze — takes place during the night; air flows from land to sea
    • b. Cyclones — violent whirling storm characterized by strong winds and rain covering large areas; created by winds converging at a Low-Pressure Area (LPA)
    • c. Thunderstorms — small cluster of storm clouds carrying heavy rain and sometimes lightning.
    • d. Tornadoes — violent twisting funnel of air
  • STORM WARNING SIGNALS

2.2. CLIMATE

• Average atmospheric conditions in a certain area over a long period of time.
• Atmospheric Variables: location, topography, distance from large bodies of water, altitude, and wind patterns.
• IMPORTANT GOVERNMENT AGENCIES FOR DISASTER PREPAREDNESS AND MITIGATION
  • Department of Science and Technology (DOST) — includes PAGASA and PHIVOLCS
  • Department of the Interior and Local Government (DILG) - Formulate plans, policies and programs which will meet local emergencies arising from natural and man-made disasters
  • National Economic and Development Authority (NEDA) — Responsible for disaster rehabilitation and recover

LESSON 3: ASTRONOMY

• Astronomy is the study of space, celestial bodies, and the behavior of the universe,

3.1. THE EARTH

• Age: about 4.5 billion years

• Surface is 29% land and 71% water

• Shape: Oblate Spheroid

• Axis tilts 23.5° from the vertical

• Mass: about 6 x $10^{24}$ kilograms

• EARTH IN MOTION

  • The Earth completes a full rotation around its axis in approximately 23 hours, 56 minutes, and 4 seconds or 24 hours.
  • The Earth completes its revolution around the Sun in approximately 365.25 days.

• RELATIVE DATING

  • Arranges geological events and the rocks they leave behind in a sequence
  • Stratigraphy (layers of rock are called strata) Is the method of reading this order or sequence
  • Note: Relative dating does not provide actual numerical dates for the rocks

• STENO’S LAWS

  • Cross-cutting relationships
    • Pertains to the formation of faults and the age of the sequences through which they cut
    • Faults are younger than the rocks they cut
    • If a fault is found penetrating some formations but not those on top of it, then the formations that were cut are older than the fault and the ones that are not cut must be younger than the fault.
  • Original Horizontality
    • The deposition of sediments occurs as essentially horizontal beds
  • Superposition
    • A sedimentary rock layer in a tectonically undisturbed sequence is younger than the one beneath it and older than the one above it
  • Lateral Continuity
    • Layers of sediment initially extend laterally in all directions; in other words, they are laterally continuous
  • Intrusive Relationships
    • Concerns crosscutting intrusions
    • An igneous intrusion cuts across a formation of sedimentary rock such that it can be determined that the igneous intrusion is younger than the sedimentary rock
  • Inclusions and Components
    • If inclusions (or clasts) are found in a formation then the inclusions must be older than the formation that contains them

• SEASONS

  • The Earth has an elliptical orbit so its distance from the Sun is not constant
  • At the aphelion (farthest point) the Earth experiences colder temperatures
  • At the perihelion (closest point) the Earth experiences hotter temperatures
  • DIFFERENT LENGTHS OF DAY:
    • The Earth’s tilted axis causes some areas of the surface to be exposed to the Sun for longer periods than others as the Earth revolves around the sun
    • Longest day - Summer Solstice
    • Shortest day - Winter Solstice
    • Equal lengths of day and night — Equinox

3.2. THE MOON

• Reflects the light of the Sun at night
• 384,400 km away from the Earth
• Circumference of 10,917 km and mass of 7.3477 x $10^{22}$ kg
• Revolves around the Earth in 27 days
• Gravitational pull of the moon causes changes on the Earth's tides

A. TIDES

• i. Apogee — farthest point of the moon from the Earth; has less gravitational pull; results to lower tides or less variation in high/low tides
• ii. Perigee — closest point of the moon to the Earth; has more gravitational pull; results to higher tides or greater variation in high/low tides
• iii. Spring Tide — high tides are higher and low tides are lower than usual
• iv. Neap Tide — high tides are lower and low tides are higher than usual

B. ECLIPSES

• Occurs when one body comes between the line of sight between two other bodies
  • Solar Eclipse — S-M-E (Sun --- Moon --- Earth); occurs approximately every 18 months but only repeats in the same location every 360 to 410 years
    • PARTS OF AN ECLIPSE SHADOW
  • Lunar Eclipse — S-E-M (Sun --- Earth --- Moon); happens during a full moon

3.3. THE SUN

• Center of the Solar System
• Has a diameter of 1,392,684 km and a mass of 1.9891 x $10^{30}$ kg
• Mostly made of hydrogen and helium

3.4. THE SOLAR SYSTEM

• PLANETS
  • Astronomical object orbiting around a star
  • Massive enough to be shaped into a sphere by its gravity
  • Types of planets:
    • a.Terrestrial Planet / Inner Planets
      • Mercury | It has two sides, a very hot day and a very cold night
      • Venus | One of the brightest celestial body seen from the Earth
      • Earth | The only known planet with living creatures
      • Mars | “red planet”
    • b.Jovian Planet / Outer Planets
      • Jupiter | Largest planet in the Solar System. Has a violent storm called the Great Red Spot
      • Saturn | It has a very complex planetary ring system
      • Uranus | Atmosphere is about 83% Hydrogen
      • Neptune | Blue in color, Prominent feature: Great Dark Spot
  • Physical Properties of Planets

3.5. OTHER ASTRONOMICAL BODIES

• i. Natural Satellites (moons) — smaller bodies orbiting around a planet
• ii. Asteroids — astronomical bodies revolving around a star but does not have enough mass to become spherical
• iii. Comets — chunks of ice revolving around a star

A. GALAXY

• Galaxy — very large collection of smaller astronomical bodies revolving around a center
• The Milky Way — the most important galaxy as it contains our Solar System.
• Types of Galaxies:
  • a. Spiral
  • b.Barred Spiral
  • c. Elliptical
  • d.Irregular

B. STARS

• A massive body of gas that can produce energy through nuclear fusion; sizes vary greatly and colors depend on the age or temperature of the star (red is the coolest, blue is the hottest).
  • CATEGORIES OF STARS:
    • i. Giants — stage when main sequence stars reach its maximum size and starts to lose energy and become a star nebula; can progress into a white dwarf
    • ii. Super Giants — when a star born is too massive to be a main sequence star, it eventually becomes a super-giant; they do not dissipate but explode instead as a supernova
    • iii. White Dwarf — dying star
• IMPORTANT CONCEPTS:
  • Nebula — immense gas cloud where stars are born
  • Main Sequence — phase in the star life cycle from its birth to near death; stage of rapid growth in size, brightness, and temperature; most stars belong in this category
  • Black Hole — end result of a supernova when all the materials of the exploded star compress due to gravity, creating a very dense Star (neutron star); strong gravitational force exist within the space previously occupied by the original supergiant
  • Quasars (quasi-stellar radio source) — most energetic and distant galactic nuclei; very luminous and transmit radio waves as red-shift waves
  • Pulsars — neutron star with high magnetic field that its electromagnetic emissions are concentrated at the magnetic poles. When the pulsar rotates, a pulsing effect similar to a light house is observed

3.6. ASTRONOMY CONCEPTS

• a. The Big Bang Theory — most recognized theory of the origin of the universe; a huge explosion occurred from a singularity and the immense energy created matter that is continually spreading outward, creating space.
• b. The Big Crunch — theory stating that with the combined gravitation of all masses in the universe, expansion will eventually stop and begin to compress back into a singularity.
• c. Divine Creation —a religious belief which states that the universe was created by a God.
• d. Light-year—the distance traveled by light in 1 year; astronomical measure of length (9.46 x $10^{12}$ km).

BIOLOGY

LESSON 1: BIOLOGY

• Biology is the study of life and living things. It is divided into 2 major branches: Zoology and Botany

1.1. CHARACTERISTICS OF LIFE

• i. HOMEOSTASIS — internal balance
• ii. ORGANIZATION — has level of organization from simplest to complex structures.
• iii. REPRODUCTION — process of creating new “offspring” individual organisms from “parents”.
• iv. IRRITABILITY — ability to respond to various stimuli.
• v. METABOLISM — sum of chemical activity of all functions.
• vi. EVOLUTION — change in characteristics of a population over a long period of time due to changes in the environment.
• vii. GROWTH — process of changing the size and form of an organism as it matures.

1.2. BIOMOLECULES

A. NUCLEIC ACIDS

• Deoxyribonucleic Acid (DNA)
  • Double-helix shape
  • Genetic blueprint of an organism
  • Basis for protein production
  • Basic unit: nucleotide (which is composed of a deoxyribose sugar, phosphate group, and nucleobase)
  • Nucleobases:
    • Purines
      • Adenine
      • Guanine
    • Pyrimidines
      • Thymine
      • Cytosine
  • Nucleotide pairings:
    • A-G;C-T
• Ribonucleic Acid (RNA)
  • A conjugate of a DNA chain wherein adenine is paired with uracil (U) instead of thymine
  • Version of the DNA used in protein production.

B. PROTEIN

• Building blocks of life
• Basic unit: amino acids (which is composed of an amino group and a carboxyl group)

C. CARBOHYDRATES

• Molecules in organisms that contain C, H, and O atoms
• Classification:
  • i. Monosaccharide — one sugar unit (Glucose, Fructose, Galactose)
  • ii. Disaccharide — two sugar units (Maltose, Sucrose, Lactose)
  • iii. Polysaccharide — three or more sugar units (Starch, Glycogen)

D. LIPIDS AND FATS

• Naturally occurring molecules that are immiscible in water and dissolved only in fat solvents.

LESSON 2: THE CELL

2.1. CELL THEORY

• i. The cell is the basic unit of structure and function in organisms
  • All living organisms and their anatomical parts are made of cells
  • All functions necessary for the survival of an organisms are ultimately performed by cells
• ii. All living organisms are made up of one or more cells.
  • Unicellular: made of one cell
  • Multicellular: made of more than one cell
• iii. All cells arise from pre-existing cells.
• The Modern Cell Theory adds the following statements:
  • iv. All cells have the same chemical composition and metabolic activities
  • v. All basic chemical and physiological functions are carried out inside cells
  • vi. The cell contains hereditary information which is passed on from cell to cell during cell division
  • vii. Cell activity depends on the activities of sub-cellular structures

2.2. PROKARYOTIC VS. EUKARYOTIC

2.3. CELL ANATOMY

• Cell Membrane / Plasma Membrane
  • Semi permeable membrane enclosing the cell separating the internal environment from the outside and serves as the location of chemical exchange for many life functions; made up of a phospholipid bilayer
• Cytoplasm
  • Internal environment of the cell; contains all of the internal organelles and the fluid medium they are suspended In
• Nucleus
  • Central storage of genetic material of the cell
  • Nuclear Membrane: Enclosure for the nucleus that serves as additional protection for its contents
  • Nucleoplasm: Environment within the nucleus
  • Nucleolus: An area within the nucleoplasm where genetic materials are concentrated
  • Nuclear Pore: Channels materials in and out of the nucleus
• Mitochondrion
  • Considered as the “powerhouse” of the cell; produces energy for use of the organism
• Lysosome
  • Site for internal digestion of food chemicals
• ER
  • Site of lipid and protein synthesis
• **Golgi