SES4U Grade 12 Earth and Space Final Exam

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Thanks, Angela!

  1. Sun, Moon, Earth Terms

Spinoff: technology developed in space program that now has common commercial uses

Ecliptic: plane of Earth’s orbit around the sun

Ejecta: material blasted out of the Moon’s surface as a result of space-object impacts

Reflecting Telescope: a device that brings visible light to a focus with mirrors

Summer solstice: Earth’s position around June 21, at which the northern hemisphere has its maximum daylight hours

Winter solstice: Earth’s position near or on December 21, at which the northern hemisphere has its minimum daylight hours

Autumnal Equinox; Earth’s position when the lengths of day and night are equal

Synchronous rotation: Moon’s state, in which its rotational period and its orbital period are equal

Mare: a dark, smooth plain on the surface of the moon

Regolith: a loose, ground-up rock on the Moon’s surface

Interferometry: a process of linking separate radio telescopes to act as one

Solar Eclipse: the blocking of the disk of the sun by the Moon

Albedo: the portion of sunlight reflected by the Moon’s surface 

Perigee: closest point to Earth in the Moon’s orbit

Apogee: farthest point from Earth in the Moon’s orbit

2. Main Ideas:

Electromagnetic spectrum is the arrangement of waves that includes gamma rays, X rays, ultraviolet radiation, visible light, infrared radiation, microwaves and radio waves according to the wavelength and frequency,

 

-The telescope that uses lenses to bring visible light to a focus is a refracting telescope

-Telescopes are placed above the atmosphere in order to most effectively collect infrared and ultraviolet radiation, X-rays, and gamma rays

-The space exploration program that landed astronauts on the Moon was Apollo

-The Moon’s surface is very different from the surface of Earth because the Moon has no erosion

-The theory that suggests the Moon was formed at about the same time as Earth and from similar materials is called the simultaneous formation theory

-The daily rising and setting of heavenly objects like Sun is caused by the rotation of Earth

-One reason different seasons occur on Earth is because Earth’s axis is tilted 23.5o relative to the ecliptic

-When the Moon waxes during its lunar cycle, the amount of its sunlight portion that we see appears to increase in size

-A lunar eclipse occurs when Earth passes between the Sun and Moon

-A lunar eclipse can only occur during the phase of the full moon

3. Earth Moon Mystery Article Q&A

1) Is the moon geologically active?

-Moon is geologically not active

-Moon is like a control- it is not as complicated as the earth is- no weathering, no plate tectonics

 

2) What was the Lunar Magma Ocean? Describe some of its characteristics

-sea of molten rock; very hot about 1 200 degrees, several hundred miles deep

3) What are the bright whitish areas called on the moon’s surface? What are the darker areas called?

 

-Bright whitish-gray areas are mountains called Lunar Highlands which is made of anorthosite (light minerals)

-Flatter grayish-black areas are called Lunar Mare which is made of basalt (lava outpourings)

4) Outline four main models of lunar formation

  1. The intact capture model: earth and moon are formed separately in solar system; relatively non-violent
  2. The coaccretion model: both bodies form from the same material at the same time
  3. Earth Fission model: earth divides out due to molten and rapid rotation
  4. Collision Ejection model: mars sized object collides with earth and moon forms out of rings of debris ejected

5) Is there a difference between the oxygen isotope data on the moon and the earth? Which model does this data support?

-Comparison of 0 isotopes in crust- similar in both the moon and earth

-> supports the earth fission model and the coaccretion model

 

6) Which model is currently favored?

-Collision Ejection Model -> because it answers some questions about the

Earth’s change in notation and its apparent change in axis

 

4. Drake Equation

 

-terms involved in estimating the number of technological civilizations that may exist in our galaxy

 

-identifies specific factors thought to play a role in the development of such civilizations

 

N=R*fpneflfifcL

 

N= the number of communicative civilizations

R*= the rate of formation of suitable stars (such as sun)

fp= the fraction of those stars with planets (current evidence

indicates that planetary systems may be common for stars like the sun)

ne= the numbers of Earth-like worlds per planetary system

fl= the fraction of those Earth-like planets where life actually develops

fi= the fraction of life sites where intelligence develops

fc= the fraction of communicative planets (those on which electromagnetic communication technology develops)

L= the “lifetime” of communicating civilization

 

*Problem with this equation is that everything passed fp is really unknown.

 

5. Seasons

 

-Moon did influence season early in our history- the collision that may have formed the moon tilted the earth’s axis at 23.5 degrees from normal

-Moon stabilized earth’s wobble

 

-Moon does not influence seasons now

 

-Seasons are not driven by how close or far we are from the sun; we are actually closer in the winter; further in the summer

 

-Seasons are driven by the tilt of the earth and what part of what hemisphere is facing the sun at which time of the year

 

6. Gravity

 

-The strength of the force of gravitation (FG) between two objects depends on the mass of the objects and the distance separating them

 

-FG is directly proportional to the product of masses

 

-FG a m1 m2 -> FG is measured in newtons

-> m1 & m2 measured in kilograms

 

-Let m1= mass of earth & m2= your mass

-> if mass of earth is doubled, FG between you and the Earth is doubled

-> if m2 is doubled, FG between you and the Earth is doubled

-> if both mass of earth and m2 is doubled, FG between you and the Earth is quadrupled

 

-FG is inversely proportional to the square of the distance between the centres of the objects -> FG a 1/d2

-The combined expression: FG = Gm1m2, where G= 6.67 x 10-11N*m2

d2                        kg2

-Therefore, gravity is a weak force

-For FG to be great, the interacting masses must be large

and/or separation must be small

 

-Why does gravitational field strength at Earth’s surface vary between

9.78m/s2 and 9.83m/s2?

 

  • “g” is greater than average at the poles because Earth’s radius at the poles is at its smallest
  • “g” is lesser than average at the equator because Earth’s radius at the equator is at its largest

 

7. Tides

 

  • Tides are the result of the gravitational effects of the Sun and Moon on Earth’s oceans

 

Spring Tide:

 

 

 

 

 

 

 

-The difference between high and low tide is at its greatest

-Occurs just after a new or full moon

 

Neap Tide:

 

 

 

 

 

 

 

 

 

 

 

-The difference between high and low tide is at its lowest

-Occurs at the first and third quarters of the moon

 

  • Why do astronauts appear to be weightless when they are in orbit?
  • Microgravity= apparent weightlessness
  • g= 9.8m/s2 at Earth’s surface, for everything!

 

8. Origins: The Earth is Born

 

– Early Earth is described as hellish, hot, bombarded and lifeless

-Sun formation may have triggered by supernova; elements such as H, He, Fe, C, all elements beyond Fe were found

-Early Earth have grown due to collision between rocks, gravitational attraction and accretion

-Asteroids and meteorites will help us get the snapshot of the early Earth

-Carbon, water and radioactive isotopes are found on that meteorite and gives us the age of solar system

-Age is about 4-4.5 billion years

-Conditions such as molten planet, bombarded from space, radioactive decay gave rise to Iron Catastrophe

-*Iron Catastrophe: heavy metals like iron and nickel migrate to the core

->this lead to differentiated planet

-*Spinning core: it protects earth by: the molten core spinning and swirling which creates electric current and magnetic field then deflects the solar wind and eventually protects the planet

Nebula: debris exists with a vast cloud of gas and dust called a nebula

 

9. Discoveries of Galileo

 

-Moon surface= rough and uneven -> the surface is covered with craters, mountains and valleys

-sunspots, landscape on moon, Jupiter moons, jail, ideas of universe

-supports Copernican idea that Earth and other planets orbit the Sun

 

10. Additional information from articles

 

  1. Describe what happened to Mars:
  • Mars too small; core cooled and solidified; no more magnetic field; no barrier to solar wind; solar wind strips atmosphere
  1. How was the Moon formed?
  • Formed as same time as Earth
  1. What did astronauts find out about age of Moon?
  • Younger than the earth; some compositions as the outer part of the earth
  1. What did the new Moon do for the early Earth?
  • Stabilized the earth rotation; reduced the earth’s wobble; 23.5 degrees from normal gives the earth seasons
  1. Where did life begin?
  • Under the surface (refuge from bombardment)
  • Under the oceans (hydro thermal vents)

 

  • Opposition: the term used to describe two celestial bodies as being opposite each other in the sky, relative to the observer. An exam is when the Moon is opposite the Sun, with the observer on the Earth in the middle

 

11. Geologic Time

 

 -Geologic Time Scale: record of Earth’s history from its origin 4.6 billion years ago to the present

-> By studying rock layer and fossils within them, geologists can reconstruct aspects of Earth’s history and interpret ancient environment

->Enables to organizes time into meaningful “chunks”, context to understand time frames

 

-Eon: the largest of time units (Hadean, Archaen, Proterozoic, Phanerozoic)

-Precambrian: unit of geologic time consisting of the first three eons during which Earth formed and became hospitable to life; makes up nearly 90% of geologic time

 

-Era: ten-hundreds of millions of years in duration (Paleozoic, Mesozoic, Cenozoic)

 

-Periods: tens of millions of years in duration

-Epochs: hundreds of thousands to millions of years in duration

 

-Bascially:

 

Eon >    Era  >  Period   > Epoch

Phanerozoic > Cenezoic >  Neogene > Holocene

Phanerozoic > Mesozoic >  Cretaceous

Phanerozoic > Paleozoic >  Silurian

Phanerozoic > Paleozoic >  Cambrian

 

-Why do scientists know more about the Cenozoic than they do about other eras?

 

  • We live in it; shorter time phrase; no time for material(rocks) and fossils to disappear

 

-Why do scientists know so little about Precambrian Era?

 

  • Long time frame; we aren’t there; lots of time for erosion

 

-Extinction events determine the divisions of eras and periods on the geologic time scale

 

-Cenozoic era is divided into both periods and epochs

 

-Geologists study fossils for paleo ecology where they can find out the patterns of life, predict and/or protect future

 

-We live in Holocene epoch, Quaternary period and Cenozoic era

-Major divisions of Earth’s history are Eras

-Each major division may be divided into periods

-The Cenozoic Era is divided into epochs

-Clues to which organisms lived in different eras are found in fossils

-A gradual change in life-forms over time is organic evolution

-After major changes in Earth’s environments, species either died out or adapted

-Organisms with traits that are suited to an environment survive by the process of natural selection

-Plate tectonics caused collision and separation of continents

-Many species adapted or became extinct because plate tectonics caused their environments to change when the continents collided or separated

-Protorozoic era lasted the longest

-Hadean era is the oldest

Order of which species appeared on Earth:

  • iron catastrophe-> origin of the moon -> great bombardment -> Origin of Life-> Cyanobacteria -> oxygen & ozone layer -> shielding of Earth from ultraviolet rays -> complex organisms (multicellular)-> invertebrates -> organisms with hard parts (shells) -> fish –amphibians -> reptiles -> Pangaea (all Earth)

-Why did coal deposits begin to form in the Paleozoic Era?

-> Formation of vast forest + swamps

 

Mass Extinction: many groups of organisms disappear from the rock record at about the same time

  • the end of Palezoic Era is marked by the largest mass extinction event in Earth; formation of Pangea and Catastrophe caused Mass Extinction in that era

What happened to all of the continental plates near the end of the Paleozoic Era? –they merged into one

 

12. Key Concepts in development of Geologic Time

 

-Up to late 1700s, Earth history was based on biblical interpretation only

Catastrophism: a belief that the varied landscapes were created by great catastrophes in history; e.g. Noah and the Flood

Uniformitarianism: the physical, chemical and biological laws that operate today have also operated in the geological past- “the key to the present is the key to the past

-time/geology/history of planet/challenge to religion point of view

 

13. Fossils

-The preserved remains or traces of once-living organisms

-> provided evidence that species have changed over time on this planet

  • fossils help determine sequence of rock layers and the relative ages of rocks
  • shows the succession of life forms

 

14. Index Fossils:

  • The fossil remains of an organism that lived in a particular geologic age, used to identify or date the rock or rock layer in which it is found
  • The best type of index fossils are usually those of swimming or floating organisms that evolved quickly and were able to spread over large areas (such as ammonites & graptolites)
  • More useful than other fossils; easily recognized, abundant, widely distributed, short time frame

 

15. Relative Dating vs. Absolute Dating

 

   -Absolute Dating: used to give an actual age (ex. Radioactive decay)

   -Relative-age Dating: used to establish the order of past geologic events (through different principles)

 

Principles of Relative Dating

Original horizontality: the principle that sedimentary rocks are deposited in horizontal or nearly horizontal layers

Cross-cutting relationships: an intrusion is younger than the rock it cuts across

Superposition: the principle that in an undisturbed rock sequence, the oldest rocks are at the bottom and each consecutive layer is younger than the layer beneath it

 

Absolute Dating – Radioactive Decay

-The atoms of some chemical elements have different forms called isotopes. These break down over time in a process called radioactive decay. Each original isotope called the parent gradually decays to form a new isotope called the daughter. When the number of parent atoms decreases, the number of daughter atoms increases by the same amount. Isotopes are important because each radioactive element decays at a constant rate. These rates of decay are known so that one can measure the proportion of parent and daughter isotopes in rocks now; one can calculate when the rocks were formed

 

Principle of inclusions: the fragments called inclusions in a rock layer must be older than the rock layer that contains them

Unconformities: gap in the rock record caused by erosion or weathering

Disconformity: when a horizontal layer of sedimentary rock overlies another horizontal layer of sedimentary rock (harder to see b/c they are flat)

Nonconformity: a layer of sedimentary rock overlies a layer of igneous

or metamorphic rock such as granite or marble, the eroded surface

is easier to identify

Angular unconformity: a horizontal layer of sedimentary rock is later laid down on top of the tilted eroded layers

 

16. Structure of Earth: chemical vs. physical properties

 

Chemical properties: Crust (silicates) – Mantle (Silicates) – Core (Iron)

Physical properties:

  1. Lithosphere: Rigid outer; subdivided into continental and oceanic lithosphere
  2. Asthenosphere(plastic): underlies the lithosephere; soft, partially molten layer
  3. Mesosphere(solid): main bulk of planet- highly viscous (firm-plastic)
  4. Outer core: liquid material
  5. Inner core: solid, high-density, nickel-iron sphere; it spins and is the source of the earth’s magnetic field

 

17. Plate tectonics & Sea Floor Spreading

 

-The theory of plate tectonics describes how the plates move, interact, and change the physical landscape

 

-The surface of earth is broken into large plates; the size and position of these plates change over time; the edges of these plates are sites of intense geologic activity such as earthquakes, volcanoes, and mountain building

 

-Sea Floor Spreading

-> the hypothesis that new ocean crust is formed at mid-ocean ridges and destroyed at deep-sea trenches; occurs in a continuous cycle of magma intrusion and spreading

 

Key Evidences to Sea Floor Spreading:

  1. Sonar
  • Allowed for mapping of ocean floor
  • Ocean has ridges and under water mountains; Mid-Atlantic Ridge and deep trenches
  1. Magnetometer
  • Picked up background hiss- turned out to be magnetic signature in the ocean rocks
  • When rocks are newly formed, any magnetic components in the rock will line up in the direction of magnetic north pole
  1. Patterns in Ocean rock magnetism
  • Rocks flipped between north&south poles in a defined pattern
  • Reversal pattern leading away from the ridge all the way to the continental shelves

*Old rock is pushed aside by a new rock

  1. Age of Ocean Rocks also varied
  • Ridge rocks- youngest, ocean floor- furthest away from the ridge being the oldest
  1. Deposition of Sediment
  • Ocean floor= spreading apart from the middle (meaning older) and is being destroyed in the trenches

 

18. Boundaries:

 

  • Convergent Boundaries: two plates move towards each other resulting in one plate sliding underneath the other
  • Divergent Boundaries: as two plates on either side of magma chamber are pulled apart, they create a void that is filled with new magma that solidifies and creates new oceanic crust
  • Transform Boundaries: two plates are sliding horizontally past one another

 

19. Driving Mechanisms

 

  1. Convection: crust cools and heats repetitively and plate pulls apart due to tension

 

 

 

 

 

 

 

 

  1. Ridge Push

 

 

 

 

 

 

 

  1. Slab Pull

 

 

 

 

 

20. Henry Hess

 

  • Figured out how plate tectonics worked
  • Worked on origin of ocean basins & island arcs, mountain building and the movement of continents
  • Suggested that continents do not move across oceanic crust but rather that the continents and oceanic crust move together; states that the seafloor separates at oceanic ridge where new crust is formed by upwelling magma; as the magma cools, the newly formed oceanic crust moves laterally away from the ridge

 

21. Subduction zone

 

  • An area where two plates move towards one another and one moves under the other; creates a trench
  • Creates earthquakes since subduction zone is a place where crustal plates are being forced down into the mantle below other crustal plates; the friction causes the plates to lock in position until the stress exceeds the shear strength of the fault zone

 

22. Problem in Australia

 

-> their geological location do not provide enough nutrient

-> they do not have earthquakes, volcanoes or any other kind of eruptions where they might help carry minerals and soils to the ground as it explodes

-> lacks of glaciers

 

23. Continental Margins

 

  1. Passive Margin:
  • Not a plate boundary; both continent and oceans are locked together as part of same plate; no trenches; volcanoes; or earthquakes
  • Ex) North America & Southern and Western margins of Australia

 

  1. Active Margin:
  • At or near plate boundaries
  • Ex) Iceland- Western North America; Nasca- South American Plate

 

24. Continental Breakups- “Breaking Up is hard to do”

 

  • Mid-continental break is preceded by continental uplift (dome); the development of mid-continental rifts
  • As continent drifts over a hotspot, it is lifted
  • As continent rises, it fractures- and rift valley is born
  • Breaking of (continental crust) involves the formation of a y-shaped break called a triple-junction; each arm is called GRABEN
  • Failure structures are called AULACOGENS; and are typically when large rivers and lakes are found

 

25. Magma/Intrusions/Volcanoes

 

  • Magma: mixture of molten rock, mineral grains and dissolve gas
  • Some factors that affect formation of Magma- to melt rock- include increase in temperature, decrease in pressure; and addition of water
  • Types of Magma
  1. Basaltic:

-low silica content; low viscosity; least explosive; from upper mantle; linked to shield volcanoes

  1. Andesitic:

-medium silica; medium viscosity; medium explosive

-along continental margins at subduction zones

-from oceanic crust and oceanic sediments

-linked to both cinder and composite volcanoes

  1. Rhyolitic:

-highest silica; highest viscosity; most explosive

-from continental crust where interaction with silica is greatest

-linked to composite volcanoes

 

  • Types of volcanoes
  1. Shield Volcanoes:

-Largest of the three types of volcanoes

-Basaltic Lava

-Quiet eruptions

  1. Cinder Cones:

-Smallest of the three types of volcanoes

-Andesitic Lava

-Explosive eruptions

  1. Composite volcanoes:

-Considerably larger than cinder cones

-Rhyolitic Lava

-Most explosive eruptions

 

  • Intrusions

 

  1. Plutons: intrusive igneous rock bodies
  2. Batholiths: irregular shaped masses of coarse grained rocks which is found in the interior of mountains
  3. Stocks: irregularly shaped plutons that are similar to batholiths but smaller in size
  4. Laccoliths: mushroom shaped pluton with round top and flat bottom; cause overlying rocks to curve upwards
  5. Sill: Pluton that intrudes parallel to rock layers
  6. Dyke: Pluton that cuts across rock layers

 

26. Pressure and Water influence

 

  1. Pressure:

-higher pressure increases the temperature for melting

-Why? -> the pressure helps hold the atoms in place; the more pressure, the more tightly the atoms are held, the greater temperature required to split them apart

-Therefore, high pressures in the mantle rocks prevent atoms within mineral from breaking chemical bonds and moving freely from one another to form a liquid (magma)

-when pressure is reduced the result is melting of the rock & when pressure increases the tock becomes hardened

 

 

  1. Water:

-small amounts of water in rock will result in a decrease in a melting temperature

-electrical polarization causes a decrease in bond strengths within minerals and so the rock will melt at lower temperatures

-in essence, the water interferes with the chemical bonds in the rock making it easier to break apart and for a liquid

 

 

27. Types of Lava

 

-> pahoehoe lava:

-surface looks silky and smooth but its texture is unpleasantly gritty and coarse because the sugar crystals, while few, have grown large

 

->’a’a lava: more rough and broken surface

 

->The major difference comes from their appearance of the surfaces and they also differ in the way they flow

 

28. Scales

 

  • Mercalli:

-based on damage

-relative scale which means that it is not based on real earthquake but rather on human infrastructure

 

  • Richer:

-Describes the earthquake’s magnitude by measuring the seismic waves that cause the earthquake

 

29. Stress/Fault/Boundary

 

 

Stress Compression

 

Tension Shear
Fault Reverse Normal Strike Slip
Boundary Convergent Divergent Transform

 

 

 

30. Waves

  1. Body Wave

-a seismic wave that moves through the interior of the earth

P wave: Primary

-> compressional-> travels in a straight line

->squeezes and pulls rocks in the same direction as wave travels

S wave: Secondary

->goes up and down; more damage

 

  1. Surface Wave

-a seismic wave that travels near the surface of the earth

Love wave:

-> a surface wave having a horizontal motion that is transverse (perpendicular) to the direction the wave is travelling

Rayleigh Wave:

->a seismic surface wave causing the ground to shake in an elliptical motion, with no transverse (가로지르다) or perpendicular motion

 

31. Hypocenter & Epicenter

 

Hypocenter: the location of earthquake under the surface

Epicenter: the point of earth’s surface directly above the focus of an earthquake

 

32. Minerals

 

-Minerals are naturally occurring, solid, inorganic material, often in crystal form; there are 4000 known minerals; ex. Halite, gold, diamond

-More than 90% of minerals are made up of oxygen and silicon

-Most minerals are compounds of various elements- top 8 make up 98.5% of the crust’s mass

-re-crystallization or formation of new minerals is response to pressure

-as pressure and temperature increase; continued re-crystallization and formation of new mineral assemblages

 

How do we identify minerals?

  • Rely on several simple tests: based on a mineral’s physical and chemical properties which are crystal form, luster, hardness, cleavage, fracture, streak, color, density, specific gravity and special properties

Crystal form: some minerals form in such distinct crystal shapes

Luster: the way minerals reflect light from its surface

Hardness: a measure of how easily a mineral can be scratched

Cleavage: when mineral splits relatively easily

Fracture: minerals that break with rough or jagged edges

Streak: colour of a mineral when it is broken up and powered

Colour: Caused by the presence of trace elements or compounds within a mineral

 

Types of Minerals

  1. Silicates:

-contains silicon and oxygen, and usually one or more other elements

-basic building block of the silicate is silica tetrahedron, a geometric solid having four sides that are equilateral triangles, resembling pyramid

2) Carbonates:

-composed of one or more metallic elements and the carbonate ion

3) Oxides:

-compounds of oxygen and a metal

4) Other groups

-include sulfides, sulfates, halides, and native elements

5) Ores:

-a mineral is an ore if it contains a valuable substance that can be minded at a profit

6) Gems:

-Valuable minerals that are prized for their rarity and beauty (rubies, emeralds, diamonds)

 

*Minerals are used as resources such as construction, energy production and jewelry making**

 

33. Rocks

 

Types of Rocks:

 

 

Igneous Rock -Form from cooling magma or lava->Intrusive rock (plutonic): cooled underground and solidified slowly; individual crystals can be easily seen by the naked eye

-> ex. granite

->Extrusive rock (volcanic): cooled quickly and solidified only after erupting onto the surface; individual crystals cannot be easily seen by the naked eye

->ex.basalt

Characteristics

-interlocking texture of grains; may display two different grain sizes; usually dark-coloured and dense; some have holes; composed of crystals

Sedimentary Rock -Form from the bonding of rock fragments such as sand, silt, or clay; from organic materials; and from chemicals dissolved in water-Clastic: formed from weathered and eroded rocks; these chunks of rocks are essentially cemented into a new rock

Chemical: formed when minerals dissolved in water precipitate out

Organic: formed from remains of living things such as clamshells, plankton skeletons, dinosaur bones, and plants

-ex. Limestone, shale

Characteristics

Grains cemented together; may sow presence of fossils; usually light-coloured and low density; show layers or bands

Metamorphic Rock -Form when other rocks are changed by heat, pressure and chemical deep inside the earth-Foliated: mineral grains re-align themselves into bands

-Non-foliated: mineral grains do not re-align themselves into bands

Characteristics

Interlocking texture of large grains; generally show foliation (layer); often show banded light and dark colours; often make “ching” sound instead of “chung”