Exam 1

Exam 1

1. Night Sky

   • Q:Motion of Stars Depends on the Earths revolution, rotation, and your location.
     • A:Depends on revolution because the north pole always points in the same direction
     • A:Depends on rotation because the rotation from the earth causes the stars to appear that they are moving in the sky.
     • A:Depends on location because that is how the seasonal and circumpolar stars are classified
   • Q:Explain the nightly apparent motion of both circumpolar and season stars.
     • A:Circumpolar stars move counter clock wise in a complete 360 degree rotation from the view of in the northern hemisphere.
     • A:Seasonal stars rise and fall in an arc formation from east to west.
   • Q:Explain why season stars are not visible all throughout the year.
     • A:Due to the earths tilt and the rotation around the sun.
   • Q:Describe the ecliptic and what objects in the sky that can be seen along it.
     • A:Ecliptic is the line the sun follows
     • A:The objects you can see in the sky are the constellations of the zodiac signs

2. Seasons and Calendars

   • Q:Describe the Gregorian calendar.
     • A:Strictly a solar calendar
   • Q:Understand the two reasons why summers are warmer than winters.
     • A:Because of earths tilt the sun is up higher in the sky
     • A:The days are longer
   • Q:Briefly describe other calendars used around the world.
     • A:Islamic, Lunar calendar and is not in sync with the Gregorian calendar.
     • A:Chinese, Lunar and Solar calendar.
     • A:Hebrew, Lunar and Solar Calendar. Has a leap month every 3 years
     • A:Julian, Solar calendar leap day is every 4 years making it 11 minutes off.
   • Q:Explain in words and drawings why the Earth exhibits seasons.
     • A:Because of Earths tilt.
   • Q:Understand how the sun moves across the sky through seasons
     • A:In the summer the sun is at a high arc.
     • A:In the winter the sun is at a low arc.

3. The Moon

   • Q: Explain why the moon exhibits phases.
     • A:Because the sun only shines on one part of the moon so when it moves around the Earth we can only see the lit part of the moon.
   • Q:Explain what cause tides and how high and low tides are predicted.
     • A:Tides are caused by the gravitational pull of the moon.
     • A:Tides are predicted by the position of the moon.
   • Q:Describe the geometry required for lunar and solar eclipses. Why do they not happen each month?
     • A: The required geometry for lunar and solar eclipses is that they have to be on the same plane.
     • A:Do not happen each month because they all have to be in one line.
   • Q:Explain why the same side of the moon always faces Earth.
     • A: Because of Earth's gravitational pull.

4. Measuring the Sky

   • Q:Describe how Eratosthenes determined the size of the Earth.
     • A:By noting the shadows of two cities on the summer solstice.
   • Q:What evidence do we have that the Earth is round.
     • A:Line of sight, Ships sink on the horizon, we can circumnavigate, and seasonal stars.
   • Q:Explain how we can determine the size of the moon relative to that of the Earth.
     • A: The Earth's shadow on the moon.
   • Q: How do we determine the distance to the Sun relative to that of the moon? What part of this is prone to error?
     • A:The Earths shadow cast on the moon during a lunar eclipse.
     • A:The Sun Moon angle is prone to error.

5. Q:Describe the scientific method and apply it to a topic we have learned in class recently.

   • A:Scientific Method, You observe, then you look for patterns, then you imagine explanations, then you predict, and then you tell people.

6. Ptolemy

   • Q: Describe the three philosophical assumptions underlying Ptolemy's model.
     • A:Planets move in at a uniform speed
     • A:Planets move on circular paths
     • A:Planets move on a combination of circular paths including a small circle called an epicycle.
   • Q:Explain retrograde motion of planets and describe how long it takes to observe this motion.
     • A:Retrograde motion is when the planets "back up" or move backward
     • A:It takes at least half a year.

7. Galileo

   • Q:Describe evidence Galileo found that conflicted with the Ptolemaic model of the solar system
     • A:He found that we have a sun-centered solar system, and that Venus has phases
   • Q: Explain what conclusions can be drawn about the Ptolemaic and Copernican models of the solar system using the fact that Venus exhibits the full phase.

8. Kepler

   • Q: Describe Kepler's three laws. To what do they apply?
     • A: Each planet moves around the sun in an elliptical orbit and the sun is at one focus.
     • A: Orbital sped of each planet is faster when it is closer to the sun, and slower when it is farthest from the sun
     • A: The length of a planet's year is proportional to the size of its orbit.
   • Q: What does the force of gravity depend on?
     • A: It depends on the mass of 2 objects and their distance from each other.
   • Q: Explain how Kepler used Tycho's data to determine the orbit of Mars.
     • A: By developing his laws of planetary motion & by analyzing his observations about planet's orbits.

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