Engage: Review a picture of the planetsExplore: Analyze clues to the solar systems’ formationExplain: Develop a class model of solar system

formation, compare with a scientifically accepted formation modelDescribe 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

systemBriefly discuss the wide diversity of life on EarthDiscuss the effects of gravity on the characteristics of an

atmosphereEvaluate: Given the characteristics of extra-solar

planets, make a supportable prediction about the characteristics of its atmosphere.

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?

Engage

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 knowPlanets: objects that orbit the Sun, are spherical and

have cleared their orbit of debrisDensity: mass/volumeGravity: the pull objects have on each other because

of their massAtmosphere: the gas gravitationally bound to a planet

What students need to do interpret graphsmake inferences from data

Explore

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.

Explore

All planets orbit in nearly the same planeAll planets revolve around the Sun

counterclockwise as viewed above Earth’s North Pole

Nearly all planets rotate counterclockwise as viewed above Earth’s North Pole

All four inner planets have a high mean densityAll four outer planets have a low mean densityAll of the giant planets have ringsEarth, Mars, meteorites and Sun are all about

4.6 billion years oldThe Sun rotates counterclockwise as viewed

above Earth’s North PoleExplore

Oldest Earth rock – 4.3 b yrs (based on radioactive dating)

Oldest Moon rock – 4.5 billion yrsOldest Mars rock – 4.6 billion yrsOldest meteorite – 4.6 billion yrsSun’s age (based on rate of nuclear reactions at

the Sun’s core) – 5.0 billion yearsMany different clues point to an old solar systemConcepts in science class are based on the best

available evidenceMost mainline religious denominations agree with

the finding of an old solar systemExplore

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 space—leaving the planets orbiting the sun.

Simulation of this process

The Origin of the Solar System

Explain

Newton’s three laws of motionNewton’s Law of Universal Gravitation

Explain

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.

Explain

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.

Explain

The mass of an object is a measure of the amount of matter in the object—usually expressed in kilograms.

Mass is not the same as weight. An object’s weight is the force that Earth’s

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.

Explain

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

1.66Explain

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 group’s response the standard (composition difference) and a key skill (infer from data)

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 additionto metals and rocks.

The ice line seems to have been between Mars andJupiter—it separates theformation of the denseterrestrial planets fromthat of the low-densityJovian planets.

Explain

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 possibleTemperature, Water, Atmosphere, Energy,

NutrientsEach 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

Extend

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.

Extend

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 1Defend your top choice with a 2-3 sentence paragraph that includes supporting evidence. Read your sentence to the class.

Extend

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) Extend

Mars

Europa

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

Extend

A combination of a planet’s 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.

Evaluate

System A characteristicsPlanet A: Upsilon

Andromedae cTwice the mass of

Jupiter0.83 AU from its star

(Earth is 1.0 AU from the Sun)

Star A: Upsilon AndromedaeNearly the same size

and temperature as the Sun

System B characteristicsPlanet 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 581About one third the

radius and mass of the Sun

T=3,000oc (Sun T=6,000oc)

Evaluate

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.

Evaluate

Upsilon Andromedae cSince 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 dSince 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.

Evaluate

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)