OGT Review

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OGT Review
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Elements

• Elements are the basic building blocks of matter.
• There are 115 known elements.
• This number changes as new elements are created
  in research labs.
• 90 elements occur in nature and fewer than half
  of them are common.

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Elements Continued

• Elements are listed on the Periodic Table of
  Elements by atomic number (number of protons).
• Elements are composed of atoms.

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Atoms

• Atoms are the smallest particle of an element
  that has the properties of that element.
• John Dalton (1803)- Modern atomic theory.
• All atoms of a particular element are alike, but
  they are different from the atoms of any other
  element.

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Atoms Continued

• Atoms are made up of protons, neutrons and
  electrons (subatomic particles).
• Protons have a positive charge ()
• Electrons have a negative charge (-)
• Neutrons have no charge

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Atoms Continued

• Protons and neutrons make up the nucleus of an
  atom.
• Electrons orbit (circle) the nucleus.
• Move around the nucleus in shells or energy
  levels.
• The further away from the nucleus a shell is, the
  more electrons it can hold and therefore it has a
  higher energy level.
• The inner most level can hold 2 electrons, the
  second can hold 8, the third up to 18 and so on.
• The outer most shell (valence) can hold no more
  than 8 electrons.

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The Periodic Table

• Elements are arranged by atomic number (number of
  protons in the nucleus).
• Vertical columns are called groups or families.
• Horizontal rows are called periods.
• Elements located in the same group have similar
  electron configurations (same number of valence
  electrons). Therefore they will react in similar
  ways.

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Changes in Matter

• Scientists know of millions of different
  substances in the world.
• How is this possible if there are only 115 known
  elements?
• Elements combine to form different substances.

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Chemical Bonds

• Atoms are held together in molecules by chemical
  bonds.
• Chemical bonds store energy.

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Ionic Bonds

• Ions are formed when an atom gains or loses an
  electron to become or -.
• Sodium (Na) can lose its valence electron to form
  a sodium ion (Na).
• Chlorine (Cl) can gain an electron to form a
  chlorine ion (Cl-).
• An ionic bond is formed when two ions of opposite
  charges (metal and nonmetal) are attracted to
  each other and form a new substance.
• NaCl Sodium Chloride (table salt).

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Covalent Bonds

• Covalent bonds are formed between atoms of two
  nonmetals.
• Electrons are shared.
• Example Carbon can share electrons with 2
  oxygen atoms (1 with each) to form carbon dioxide
  (CO2).
• Covalent bonds are stronger than ionic bonds
  because of this sharing of electrons.

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pH

• The pH scale refers to strength of an acid or a
  base.
• The scale ranges from 0-14.
• 0 is the most acidic. (hydrochloric acid)
• 14 is the most basic. (sodium hydroxide)
• 7 is neutral. (water)

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Chemical Equations Continued

• Chemical equations must be balanced. This means
  that each element appears the same number of
  times in both the reactants and products.
• Example
• C O2 ? CO2

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• If there are different amounts of each element on
  either side of an equation we must balance it
  using coefficients.
• Example
• H2 O2 ? H2O
• This is not balanced. To balance we add
  coefficients.
• 2 H2 O2 ? 2 H2O

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States of Energy

• Potential Energy (PE) Stored energy
• Gasoline (chemical)
• Rock on a cliff (position)
• Food (chemical)
• Coal (chemical)

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• Kinetic Energy (KE) energy an object has when
  it is moving.
• Falling rock
• Thrown ball
• Runner
• Waterfall

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Fission Chain Reaction
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Nuclear Fusion
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Conduction

• Conduction is the transfer of heat by direct
  molecular contact.
• Metals are good conductors of heat.
• Example If you hold a metal rod in fire the
  heat will quickly distribute between the
  molecules in the rod and it will become hot.

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Convection

• Convection is the transfer of heat by the flow of
  a liquid or a gas.
• Warm air in a room rises and cool air sinks.
  This causes a circular motion called a convection
  current.

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Radiation

• Radiation is the transfer of heat through space
  in the form of waves.
• Heat from the sun travels through the vacuum of
  space to reach Earth.

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Wave Diagram
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What is Force?

• A force is a push or pull that is exerted on an
  object.
• Force stops motion gloved hand catching a ball
• Force slows motion friction slowing a
  skateboard
• Force changes direction tennis racket striking
  a tennis ball

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Gravity

• Law of Universal Gravitation states that in the
  universe every mass attracts every other mass.
• Greater mass greater gravitational force
• An apple falls to Earth because the Earth is much
  more massive.

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Friction

• Friction is a force that resists motion.
• It must be overcome to start an object moving
  and/or to keep it moving.
• Rougher surfaceHeavy object More friction
• Smooth surfaceLight object Less friction

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Speed and Velocity

• Speed and velocity are terms used to describe the
  motion of an object.
• Speed is the distance traveled over a certain
  period of time.
• Velocity is the same but includes a specific
  direction (north, east, southwest, etc.)

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• The equation used to determine both speed and
  velocity is distance divided by time.
• S d/t V d/t
• Units for measuring speed/velocity
• Kilometers/hour (km/hr)
• Miles/hour (mi/hr)
• Feet/second (ft/s)
• Meters/minute (m/min)
• Centimeters/second (cm/s)

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Acceleration

• Acceleration is the rate in change in velocity.
• Can be used to describe increase or decrease
  (deceleration).
• Acceleration is calculated by subtracting an
  objects starting velocity from its final
  velocity and dividing by time.
• A vf vs / t

Lay a Patch!!!
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Motion of falling objects

• Gravity causes objects released above Earths
  surface to fall to the ground.
• Mass, size and shape of the object determines how
  fast it will fall.
• Air resistance (air drag) also affects falling
  objects.
• In a vacuum (no air) all objects will fall at the
  same rate because gravity is the only force
  acting on them.

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Spheres

• The Earth consists of 3 spheres
• The lithosphere (rock sphere)
• The hydrosphere (water sphere)
• The atmosphere (gas sphere)
• All smaller parts of the Biosphere The place
  where all life exists on Earth.

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Interaction of Air, Land, and Water

• Weathering is the breaking down of rocks into
  smaller pieces.
• Physical weathering water seeps into cracks in
  rock and freezes, the water expands, breaking the
  rock apart.
• Chemical weathering oxygen and water chemically
  react with iron mineral in rocks, turning to
  rust, which crumbles away easily.

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Erosion

• Erosion is the process by which rock material at
  Earths surface is removed and carried away.
• Erosion requires a moving force (like water).
• Example Streams and rivers turn a muddy brown
  after a heavy rain due to the rock material in
  the water.
• Glaciers and wind can also contribute to erosion.

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Structure of the Earth

• The Earth is composed of 3 layers.
• The crust outermost layer (5-50 km)
• The mantle middle layer (2900 km)
• The core innermost layer
• Outer core (2300 km)
• Inner core (1200 km) Thought to be solid.

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Theory of Continental Drift

• 1912 Alfred Wegener proposed the continents
  were drifting across Earths surface.
• Based on how the shapes of the continents fit
  together like a puzzle.
• Timetable on pg. 157 shows how the theory
  developed from Wegener to the mapping of the
  ocean floor in the 1970s

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Plate Tectonics

• Earths crust is broken into pieces, or plates,
  that slowly move and interact at their boundaries
  in various ways.
• Caused by heat circulating in the mantle.
• There are 10 major plates The Pacific, North
  American, Nazca, Cocos, South American, African,
  Arabian, Eurasian, Indian, and Antarctic.

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Plate Interactions

• As the plates move, some are colliding, some are
  spreading apart, and some are sliding past one
  another.
• Subduction zone When an oceanic plate collides
  with a continental plate it tends to slide down
  under it. This forms mountains and volcanoes.
• Fault zones When one plate slides sideways past
  another. This sometimes causes severe
  earthquakes.

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Earths Geologic History

• Scientists have pieced together much of Earths
  history by studying rocks.
• There are 3 main rock types
• Sedimentary
• Igneous
• Metamorphic

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Sedimentary Rock

• Most commonly formed by the deposition of
  particles underwater. (dirt being submerged)
• About 75 of land surface is covered with
  sedimentary rocks.

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Igneous Rock

• Form from hot molten rock material, either
  underground (magma) or on Earths surface (lava)
• Volcanoes

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Metamorphic Rock

• Form from pre-existing rocks that undergo changes
  caused by extreme heat and/or pressure.
• Plate motions

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Distances in Space

• Distances in space are so great they are
  difficult to comprehend.
• The distance between Earth and the nearest star
  (besides the sun) is 41,000,000,000,000 km. (41
  trillion)
• We use light-years to express distances in space.
• A light-year is the distance light travels in a
  year.

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The Big Bang Theory

• According to this theory, all the matter and
  energy that exists in the universe today was once
  concentrated in a very small, dense object about
  the size of an atom.
• For some unknown reason this object suddenly
  expanded (in a big bang) creating the beginning
  of space and time.
• Matter continued to move away and over time small
  amounts combined to form stars and planets.

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Evidence

• The universe is expanding outward.
• Galaxies are slowly moving apart.
• Galaxies are determined to be about 15 billion
  years old.
• Large quantities of a hydrogen isotope are
  scattered throughout the universe (remnants of
  big bang).

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The Solar System

• Scientists believe that our solar system formed
  about 5 billion years ago.
• After the Big Bang some gases and dust became
  our star (sun).
• The leftover material condensed into planets,
  satellites, comets, meteoroids and asteroids.
• The sun contains 99 of all matter in our solar
  system.

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Types of Symbiosis

• Mutualism When both organisms benefit.
  (butterfly/flower)
• Commensalism When one organism benefits and the
  other is not affected. (remora/shark)
• Parasitism When one organism benefits and the
  other is harmed. (tapeworm/animal)

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Mutualism
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Commensalism
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Parasitism
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Overpopulation

• Overpopulation, competition, and changes in the
  environment challenge the survival of all
  individuals within a population (same species).
• More individuals than the environment can
  support.
• Competition for resources food, territory,
  shelter and mates.
• Most do not survive to reproduce.

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Variations

• Due to variations (differences) among members of
  a species, some individuals are better adapted.
• These organisms survive to reproduce while others
  die out.
• Natural Selection Survival of the Fittest,
  Only the Strong Survive etc. Darwins Theory

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NATURAL SELECTION
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A major misconception about natural selection!
http//evolution.berkeley.edu/evosite/misconceps/I
Eneeds.shtml
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Evolution the basics

• 1. over population
• 2. constant struggle for resources
• 3. variation in the species
• 4. the best adapted to the environment survive
• 5. surviving organisms transmit variation to
  offspring

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Random facts

• ATP cellular energy
• CO2 and O2 photosynthesis
• Flagella motion
• Mitochondria energy
• Placebo fake drug
• Control group? the group that gets nothing