GS106 Lab 1 and 2 Answer Key. Light Year - distance traveled at the speed of light for a duration of 1 Earth year

Transcription

1 c:\wou\gs106\labkey\lab2key.wpd GS106 Lab 1 and 2 Answer Key READING QUESTIONS Four phases of moon: new, first quarter, full, third quarter AU = astronomical unit (a unit of distance) = average distance from Earth to the Sun ~93,000,000 mi Light Year - distance traveled at the speed of light for a duration of 1 Earth year Light Minute - distance traveled at the speed of light for a duration of 1 Earth minute Dist. from Sun to Earth ~93,000,000 mi 23.5 degrees is the angle of tilt of the Earth's axis from perpendicular, relative to the plane of the ecliptic Eccentricity - shape of the planetary orbit about the sun (a perfectly circular orbit = 0) Earth Eccentricity = , a relatively circular orbit Direct Sunlight - focus of sun light is perpendicular to the surface of the Earth (highest amount of solar radiation or "insolation") Indirect Sunlight - focus of sun light is at an acute (< 90 deg.) angle relative to the surface of the Earth (lower insolation) PRE-LAB ASSESSMENTS Pre-Existing knowledge will vary according to groups, but here are the important answers for this section... List of Planets: increasing away from sun: mercury, Venus, earth, mars, Jupiter, Saturn, Uranus, Neptune, Plato Planets we commonly see without a telescope: "evening stars": mercury, Venus, mars... etc. Why do we have seasons on Earth: because of the 23.5 degree tilt of the Earth's axis of rotation compared to the plane of the ecliptic, and the revolution of the Earth about the Sun. What causes phases of the moon?: Position of the Earth and moon relative to the Sun, the revolution of the Moon about the Sun, and the illuminated vs. shadowed portions of the Moon. Smallest Planet: Pluto, Largest Planet: Jupiter How have we deduced the physical properties of the planets without visiting there directly?: 1

2 Through the use of telescopes and physical relationships, direct visual observation. 1 - Scale Model of the Solar System Scale of your model varies by groups Scale of Planet Size (using sun): 34 in (on the model) = 1,392,00 km (diameter on the sun)... dividing both sides by in (model) = 40,941 km (on the sun) Spacing of planets pattern: Distance between planets roughly increases with distance away from the sun General patterns about sizes of planets: small interior planets (< radius for Merc., Ven., Earth, Mars) Large exterior planets (Jup., Sat., Ur., Neptune) Plato is odd ball... small diameter 2. Sun-Earth-Moon Relations See Attached Sheets with Moon Phase Diagrams... Other Related Questions What is the time between two successive full moons? Space Facts says 27.3 days Orbital Period of Moon around Earth: 27.3 Days Time between a full and new moon: ~14 days Full moon in west...time of day?... in early A.M. (the full moon rises in the east in the evening, and sets in the west in the AM) Why do we see phases of the moon?... all because of the orientation of the moon relative to the sun and the Earth. When the illuminated moon is opposite the sun from the Earth = full moon. When the shadow of the moon is facing the Earth = New Moon... the moon orbits in a counterclockwise direction around the Earth, when looking down on the objects, from above. 3 - The Seasons Direct sunlight photometer reading ~70 microamps Indirect sunlight photometer reading ~ 35 microamps Refer to the diagram of Earth seasons (see next page) 2

3 Other Questions: More sunlight hits the Earth's surface at the direct angle The southern and northern hemispheres have opposite seasons because of the 23.5 degree tilt of the Earth relative to the plane of the ecliptic, and the relation of the sun and Earth as the Earth orbits around the Sun. Table Results Pt. A S. Hem. Summer Pt. B S. Hem. Winter Pt. C S. Hem. Fall Pt. D S. Hem. Spring N. Hem. Winter N. Hem. Summer N. Hem. Spring N. Hem. Fall One Earth Day = rotation of the Earth on it's axis, 1/24 hrs See Diagram on Next Page for Explanation of Earth Seasons 3

4 4 - Classifying Planets Example Grouping of Physical Properties Inner Planets = denser, smaller diameter, shorter orbital period Outer Planets (except Plato) = less dense, larger diameter, longer orbital periods General Patterns of Planets Inner Planets (Mercury, Venus, Earth, Mars): small diameter, rocky composition, high density, warm surface temperatures Outer Planets (Jupiter, Saturn, Uranus, Neptune): large diameter, less dense, cooler surface temperatures Which Planet Would Float in Water? - Saturn Jupiter Day = 9.9 Earth Hours Venus Day = Earth Hours Earth Years comprising a Jupiter year? = 11.9 Earth Yrs 2 planets with 90% of mass in Solar System: Jupiter and Saturn Unusually Hot Planet: Venus, why? 96.5% of Venus atmosphere = carbon dioxide (a greenhouse gas). Density Relations Air 833 x less dense than water Rock 3 x more dense than water Metal at high pressure: 10,000 x more dense than water Density comparison / planet composition 5 - Graphing Planet Data Mercury = "rock", Venus = "rock", Earth = "rock", Mars = "rock", Jupiter = "ice and gas", Saturn = "gas", Uranus = "ice", Neptune = "ice", Plato = "ice and rock" Make sure you know how to plot an X-Y graph, see your instructor before the quiz if you don't know or are rusty. Graphs vary according to groups and individual students. General Trends and Relationships 1) Outer planets are more massive than inner, except Pluto (Jupiter is most massive) 4

5 2) Outer planets have greater radius than inner, except Pluto (Jupter is largest) 3) Outer planets are less dense than the inner 4) The surface temperature decreases with increasing distance from the Sun 5) Orbital period increases with increasing distance from Sun (planet years increase with distance from sun) 6) It does not appear that surface temperature has any direct relationship to mass, it is more constrained by distance from Sun 7) The greater the mass, the shorter the rotational period (i.e. faster the rotation), in general Post-Lab Assessments (important points) All models made: solar system (sun/planets), Earth-Moon-Sun relationship, Earth Climate / orbit Models are visual aids that help understanding concepts. Planet Characteristics that are similar Earth Mass Density Atmosphere Similar Planets to Earth Mercury, Ven, Earth, Mars, Pluto Mercury, Venus, Earth, Mars, Pluto Earth is Unique (that's why we are here!!!) Earth Mass Density Atmosphere Different Planets Jupiter, Saturn, Uranus, Neptune Jupiter, Saturn, Uranus, Neptune Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto 5