Engage: Review a picture of the planets

1
Solar System Lesson for Wednesday

• Engage Review a picture of the planets
• Explore Analyze clues to the solar systems
  formation
• Explain Develop a class model of solar system
  formation, compare with a scientifically accepted
  formation model
• Describe the concepts of gravity
• Relate to general make-up of the solar system
• Extend Life in the solar system
• Hypothesize where life might be possible in the
  solar system
• Briefly discuss the wide diversity of life on
  Earth
• Discuss the effects of gravity on the
  characteristics of an atmosphere
• Evaluate Given the characteristics of
  extra-solar planets, make a supportable
  prediction about the characteristics of its
  atmosphere.

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Eight planets of our solar system

• Compare/contrast the 8 planets in our solar
  system with each other.
• How are they alike? How are they different?
• Is there a pattern to their similarities or
  differences?

3
General lesson learning progression

• Learning target Earth is the third planet from
  the Sun in a system with eight planets. These
  planets differ in size, composition, and
  atmosphere. These differences originated very
  early in the formation of the solar system (6-8
  ES1B)
• What students need to know
• Planets objects that orbit the Sun, are
  spherical and have cleared their orbit of debris
• Density mass/volume
• Gravity the pull objects have on each other
  because of their mass
• Atmosphere the gas gravitationally bound to a
  planet
• What students need to do
• interpret graphs
• make inferences from data

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Solar System formation activity

• You will get a clue (observable fact) about the
  formation of the solar system
• 1. What does your single clue tell you about how
  the solar system was formed? 
• 2. Find two classmates with different clues. What
  does the set of three clues tell you about how
  the solar system was formed? 
• 3. Look at all of the clues. What does the set of
  all of the clues tell you about how the solar
  system was formed? Relate each inference you make
  to a specific clue
• 4. Each group will pick a representative
  description to read to the class.

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Solar system formation clues

• All planets orbit in nearly the same plane
• All planets revolve around the Sun
  counterclockwise as viewed above Earths North
  Pole
• Nearly all planets rotate counterclockwise as
  viewed above Earths North Pole
• All four inner planets have a high mean density
• All four outer planets have a low mean density
• All of the giant planets have rings
• Earth, Mars, meteorites and Sun are all about 4.6
  billion years old
• The Sun rotates counterclockwise as viewed above
  Earths North Pole

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More about ages

• Oldest Earth rock 4.3 b yrs (based on
  radioactive dating)
• Oldest Moon rock 4.5 billion yrs
• Oldest Mars rock 4.6 billion yrs
• Oldest meteorite 4.6 billion yrs
• Suns age (based on rate of nuclear reactions at
  the Suns core) 5.0 billion years
• Many different clues point to an old solar system
• Concepts in science class are based on the best
  available evidence
• Most mainline religious denominations agree with
  the finding of an old solar system

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The Origin of the Solar System

• Our own planetary system formed in such a
  disk-shaped cloud around the sun.
• When the sun became luminous enough, the
  remaining gas and dust were blown away into
  spaceleaving the planets orbiting the sun.
• Simulation of this process

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Main builder of the solar system Gravity

• Newtons three laws of motion
• Newtons Law of Universal Gravitation

9
Newton's three laws of motion

• From his study of the work of Galileo, Kepler,
  and others, Newton extracted three laws that
  relate the motion of a body to the forces acting
  on it.

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Newton's law of universal gravitation

• Forces occur in pairs.
• Gravity must be universal.
• That is, all objects that contain mass must
  attract all other masses in the universe.
• The force of gravity decreases as the square of
  the distance between the objects increases.
• If the distance from the Earth to the moon were
  doubled, the gravitational force between them
  would decrease by a factor of 22, or 4.
• If the distance were tripled, the force would
  decrease by a factor of 32, or 9.
• This relationship is known as the inverse square
  relation.

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"Misconception minute" Mass vs weight

• The mass of an object is a measure of the amount
  of matter in the objectusually expressed in
  kilograms.
• Mass is not the same as weight.
• An objects weight is the force that Earths
  gravity exerts on the object.
• Thus, an object in space far from Earth might
  have no weight.
• However, it would contain the same amount of
  matter and would thus have the same mass that it
  has on Earth.

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Planet densities

• What general pattern(s) do you observe about the
  density variation?
• How does this pattern relate to the accepted
  model of solar system formation?
• Write your answers in your notebook.
• Pick a representative entry to read to the class.

Planet Mean density (g/cm3)
Mercury 5.42
Venus 5.24
Earth 5.50
Mars 3.94
Jupiter 1.31
Saturn 0.70
Uranus 1.30
Neptune 1.66
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Formative feedback loop for composition
Solicit student evidence Asked question about
planet density variation and relationship to our
model
Evaluate student understanding Each group read
their response.
Provide standards-focused feedback Related each
groups response the standard (composition
difference) and a key skill (infer from data)
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• Big picture statement of solar system formation
  The important factor was temperature.
• The inner nebula was hot, and only metals and
  rock could condense there.
• The cold outer nebula could
• form lots of ices in addition
• to metals and rocks.
• The ice line seems to have
• been between Mars and
• Jupiterit separates the
• formation of the dense
• terrestrial planets from
• that of the low-density
• Jovian planets.

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Applying your knowledge

• You will apply your knowledge about planet
  characteristics and density to infer where in the
  solar system, besides Earth, life might be found.
• Five main criteria to investigate to determine if
  life is possible
• Temperature, Water, Atmosphere, Energy, Nutrients
• Each group will decide whether life is likely,
  possible or unlikely for each object.
• Decide on your top three candidates for life (in
  order, excluding Earth)
• Trading cards and other astrobiology curriculum

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Omak choices most likely for life
Object 1st place pts 2nd place pts 3rd place pts Total







Defend your top choice with a 2-3 sentence
paragraph that includes supporting evidence. Read
your sentence to the class.
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Wenatchee choices most likely for life
Object 1st place pts 2nd place pts 3rd place pts Total
Titan 3 4 2 9
Europa 3 8 2 13
Mars 18 1 19
Callisto 2 1 3
Ganyemede 1 1
Io 2 2
Moon 1 1
Defend your top choice with a 2-3 sentence
paragraph that includes supporting evidence. Read
your sentence to the class.
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Extreme Environments on Earth

1. Sea Ice (extreme cold)
2. Hydrothermal vents (extreme heat and high metal
   content)
3. Sulfuric Springs (extreme heat and highly acidic)
4. Salt Lake (extreme salt concentrations)
5. Soda Lake (extreme salt concentration and highly
   alkaline)

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Importance of Extremophiles Astrobiological
Implications

• Extreme environments on Earth are thought to be
  very similar to extreme environments that exist
  elsewhere in space
• Microorganisms that thrive in Earth extreme
  environments are thought to be likely candidates
  for the types of biota that may exist in
  extraterrestrial habitats
• Mars is postulated to have extremophilic regions
  including permafrost, hydrothermal vents, and
  evaporite crystals
• Europa is thought to have a subsurface ocean

Mars
Europa
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Planetary atmospheres

• A combination of a planets gravity and surface
  temperature influence its atmosphere.
• Larger planets have a greater gravitational pull
  on particles in their atmosphere.
• The mean velocity of a bunch of particles is set
  by the temperature of the planet's surface.
• Light elements are moving faster than the heavy
  elements and can reach escape velocity.

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Mystery planet atmospheres

• System A characteristics
• Planet A Upsilon Andromedae c
• Twice the mass of Jupiter
• 0.83 AU from its star (Earth is 1.0 AU from the
  Sun)
• Star A Upsilon Andromedae
• Nearly the same size and temperature as the Sun

• System B characteristics
• Planet B Gliese 581 d
• 7X the mass of Earth (Uranus is 14X mass of
  Earth)
• About 0.2 AU from its star (Mercury is 0.4 AU
  from the Sun)
• Star B Gliese 581
• About one third the radius and mass of the Sun
• T3,000oc (Sun T6,000oc)

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Mystery planet atmospheres

• Use the planet and star characteristics as well
  as the escape velocity vs. temperature graph to
  make a supportable prediction about the
  atmosphere of each mystery planet.
• Write your predictions and supporting evidence in
  your notebook.
• Pick a representative prediction (with support)
  to read to the class.

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Sample supportable predictions

• Upsilon Andromedae c
• Since this planet is more massive than Jupiter,
  it has a large gravitational pull and higher
  escape velocity than Jupiter.
• It is closer to its star than Jupiter but the
  additional heat does not make many particles in
  the atmosphere move fast enough to escape.
• This planet has an atmosphere dominated by H and
  He.

• Gliese 581 d
• Since this planet is half the mass of Uranus, it
  has a smaller escape velocity.
• It is closer to its star than Mercury but its
  star is much cooler than the Sun meaning it will
  be cooler and the atmosphere particles not moving
  as fast.
• This planet would probably be located near or
  below the He line on the graph meaning it would
  have little or no H and could be more Earth-like.

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Formative feedback loop for atmosphere
Solicit student evidence Asked question about
planet atmosphere
Evaluate student understanding Instructor
briefly read each student response.
Provide standards-focused feedback Related each
response the standard (atmosphere difference) and
a key skill (infer from data)