Name ANSWER KEY Class Table Seat Date

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1 Directions: Answer the following open ended review questions. Utilize a diagram where appropriate and do make sure that you label and describe the drawing. EARTH S MOTIONS: 1. Describe how Earth moves through space. Earth moves through space by revolving around the Sun in an orbit and rotating on its axis. In addition, Earth s rotation keeps it upright and as a result wobbles on its axis. This wobble is referred to as its precession. 2. How does Earth s motion relate to time? Earth s rotation on its axis takes 1 day or 24 hours. Earth s revolution accounts for our year, it takes days to revolve and orbit the Sun once. 3. What is the cause of day/night cycle on Earth? Earth moves through space by revolving around the Sun in an orbit and rotating on its axis. In addition, Earth s rotation keeps it upright and as a result wobbles on its axis. This wobble is referred to as its precession. 4. Describe a piece of evidence that supports the idea that Earth is rotating on its axis. A pendulum suspended above Earth s surface provides evidence that Earth is rotating on its Axis. Once a pendulum is set in motion it will continue to move in the same direction. As the pendulum swings, Earth rotates underneath the pendulum. An observer on the ground would see that the Pendulum appears to change direction, but a pendulum cannot change directions. The result is that Earth must rotate underneath the pendulum. SEASON S: 5. What is the cause of the seasons on Earth and the factors that help determine the season? Earth s seasons are caused by a combination of Earth revolution around the sun and it s degree tilt. As a result different geographical regions receive changing angle of rays and length of days. When the Sun s rays strike at a lower angle over less time the geographical region will become colder. On the other hand, when the Sun s rays strike at a higher angle over more time, the geographical region becomes warmer. 6. What is the angle at which Earth s axis is tilted? Why is this important? Earth is tilted on its axis at a 23.5-degree tilt. This is important because it causes different angles are which the sunlight strikes Earth s surface and different amounts of time the sun will be over a geographical region.

2 7. Draw a diagram of Earth for each season below. Label the following; all-important latitudes, hours of daylight at each latitude, lightly shade in the night, and indicate the date. Fall Equinox (Autumnal) September 22,23 Winter Solstice December 21, Summer Solstice June 20,21 Spring Equinox March 20, For each season above, draw the position of the sun in the sky at noon and the accompanying shadow of the building (Relate this same to the tree on your paper). Fall Equinox (Autumnal) Winter Solstice Summer Solstice Spring Equinox

3 GRAVITY AND ORBITAL MOTION: 9. What is the Universal law of gravity? The Universal Law of Gravity is the force of attraction between all objects in the universe due to an objects mass. Because objects have mass they bend the fabric of space-time, just like a bowling ball would bend the fabric of a trampoline. The more massive the object, the more it bends space and time. 10. Describe the 2 factors that determine the strength of the force of gravity? The two factors that determine the strength of gravity between two objects are the combined objects mass and the distance the objects are apart from one another. 11. What happens to the force of gravity when distance between 2 objects decrease? When the distance between two objects decrease, the strength of gravity will increase. The closer two objects are, the greater the gravitational force (an inverse relationship).. What happens to the force of gravity when the mass of an object increases? When the mass of two objects combined increase, the strength of gravity will increase. The more mass, the greater the gravitational force (a direct relationship). 13. Draw a diagram of an astronaut orbiting the Earth. Draw 2 arrows to indicate the factors that create its orbit and then describe why the astronaut would feel weightless. An astronaut would feel weightless because he/she is in a constant state of free-fall. There is no force pushing back on the astronaut and therefore he/she does not feel his/her weight even though gravity is still pulling on him/her. As gravity pulls in, the forward inertia acts at a right angle. The resulting path is a curve. Since the Earth, Moon, etc. are spheroids; the astronaut follows the curved path of the object he/she is orbiting. Orbital Path Gravity Inertia THE MOON 14. Describe the relationship between the Earth and its Moon in terms of their relative motion. The Earth and Moon together make up the Earth-Moon System. Although it appears that the moon orbits the Earth, the moon actually orbits a common center of gravity between the Earth and the Moon. It is located 900 miles from Earth surface and it is this point that revolves around the Sun. 15. Do we see the entire Moon from Earth? Why or why not. No we do not see the entire surface of the Moon. Only half of the Moon can be lit by the Sun at one time. In addition, the Moon is in a synchronous orbit around the Earth-Moon barycenter and revolves and rotates at the same rate. Therefore the near side of the Moon always faces Earth and the far side always faces away.

4 16. Where does the light of the Moon we see come from? The light we see from the Moon is reflected off the Moon s surface from the Sun. 17. Why does the Sun and the Moon appear similar in size? The Sun and the Moon have the same angular diameter. The Sun is 400x the size of the moon, but the Moon is 400x closer to Earth than the Sun. This cancels out the size difference between the Sun and Moon and observers from Earth see them as roughly the same size. 18. Describe what moon phases are and what determines the moon phase an observer would see? Moon phases are the portion of the lit Moon as seen from Earth. Moon phases are caused by the relative positions of the Sun, Earth, and Moon. As we observe the Moon from Earth, we see certain parts of the lit Moon. 19. Draw the phases of the moon in the appropriate box. Remember to shade in the shade, the label each moon phase. New Waxing Crescent 1 st Quarter Waxing Gibbous FULL Waning Gibbous 3 rd Quarter Waning Crescent New 20. Draw the position of the moon in respect to the Earth and Sun if the following moon phase is seen from Earth. The dark area is the area not seen. PHASE: Waning Crescent PHASE: 1 st Quarter PHASE: Waxing Gibbous PHASE: Waxing Crescent PHASE: Full Moon PHASE: Waning Gibbous PHASE: New Moon PHASE: 3 rd Quarter

5 21. What are the two types of eclipses? Draw a picture of each. The drawing should include the Moon, Earth, Sun, Umbra and Penumbra. Identify the lunar phase each Moon is in as well. SOLAR ECLIPSE LUNAR ECLIPSE New Moon Umbra Penumbra Umbra Penumbra Full Moon Penumbra 22. Why don t we experience a solar or lunar eclipse each time there is a full or new moon? The plane of the Moon s orbit is tilted approximately 5-degrees in reference to the Earth s orbit around the Sun. This means that the Moon is either above or below the Sun-Earth orbit. Only twice a year is there a possibility of a lunar or solar eclipse to occur. 23. What is the cause of tides on Earth. The tides are caused by the gravitational pull from the Moon and partially the Sun. 24. Why do most geographical places on Earth go through 2 tidal cycles? The Moon s gravity creates two tidal bulges; one on either side of the moon. The low tides are perpendicular to the high tides. The tides follow the Moon s revolution, which is much slower than Earth s rotation. On a daily basis, Earth will rotate through a high tide, low tide, high tide, and then a low tide in a 24-hour period. 25. What causes Earth to experience 2 tidal bulges; one on either side of the Moon? Two tidal bulges or high tides are a result of two factors. The first is the fact that gravity weakens with distance. The Moon will pull harder on the water closer to the Moon than the water on the opposite side. In addition, Earth is moving around the common center of gravity between the Earth-Moon System. This barycenter is located on the same side of the Moon. This creates an outward force, like a Gravitron ride at the fair, in which the water bulges on the opposite side as the Moon. 26. How long does a tide cycle last? The time between high tide and low tide is roughly about 6 hours (a little more). The total tidal cycle from high tide, to low tide, back to high tide is about hours and 25 min. in most places.

6 27. Draw a picture of a Neap Tide and a Spring Tide. In the diagram, include the Sun, Moon and Earth. Label the phase of the Moon and also draw the tidal bulges. Spring Tide Neap Tide Planetary Laws of Motion 28. Identify the 3 laws of planetary motion in each box below, write a description of each law and in the box below draw a diagram to represent the motion. 1 st Law: All orbits are elliptical with the sun at one focus of the ellipse and nothing at the other focus. 2 nd Law: A planet will sweep out equal area in equal time. When the planet is closer to the Sun it will be moving the fastest because gravitational attraction is greater. When the planet is farthest from the Sun, it will be moving the slowest because gravity weakens with distance. Diagram Diagram Diagram 3 rd Law: The closer the planet is to the Sun, the shorter the period of revolution. The farther from the Sun, the longer the period of revolution. The Solar System 29. Identify the theory that most scientist accept as to the origin of the Solar System. The Dust Cloud Theory describes the theory that most scientist accept as to the origin of the Solar System. The Solar System started as a Nebula or cloud of gas and dust. The Nebula began to condense under its own gravity. As it condensed the cloud started to spin, compress and flatten out into a disc shape. The compression caused the cloud to heat up and spark the process of nuclear fusion in the center creating a protostar. Eventually globs of material started to collide and stick together and became planetesimals. The inner planetesimals condensed more under hotter conditions and became rocky planets while the outer planets where not as hot and where left as gas

7 giants unable to condense. The planetesimals sweep out their orbits and the solar system was created. 30. Describe the organization and relative size of the objects in the solar system. SUN Inner Planets Asteroids Outer Planets Pluto Kuiper Belt Comets Oort Cloud 31. Why are the inner planets rocky and the outer planets gas? The Inner Planets are rocky and smaller due to the conditions under which they formed. The hot conditions in which the planetesimals were created, allowed the inner planets to condense and build bigger and heavier elements. The Outer Planets are gas giants. The cold conditions under which they formed kept the gasses from condensing keeping the material light and spread out. 32. Describe the difference between the inner and outer planets. INNER PLANETS OUTER PLANETS Size Small Huge Surface Solid Rocky Surface Balls of Gas with No Surface Density Greater Density Smaller Density Atmosphere Varied Atmosphere Similar Atmospheres Discovery Known by the ancients Not Known by the ancients Rotation Spin Slowly Spin Quickly Orbit Orbit Fast Orbit Slow Moons Few Moons Lots of Moons Rings No Rings Lots of Rings Visits Multiple Space Craft Visits One space craft visit (same) 33. Describe the difference between a Meteoroid, Meteor, and Meteorite. A meteoroid is a small chuck of rock in space. A meteor is a meteoroid that enters Earth s atmosphere and burns up. A meteorite is a meteor that strikes Earth s surface. 34. Why is Pluto considered a dwarf planet? What region is Pluto located in and what objects in the solar system can be found in this region? In order to be considered a planet, the object must have these 3 characteristics. 1. YES: Orbit the Sun 2. YES: Sufficient mass to have rounded itself 3. NO: Cleared and ordered its orbit. Pluto has the first 2 but lacks the 3 rd characteristic and has not cleared its orbit. Pluto is located in a region known as the Kuiper belt. The Kuiper Belt is a region that extends past Neptunes orbit. Comets come from this region.

8 THE SUN, RADIANT ENERGY, AND THE UNIVERSE 35. Describe what nuclear fusion is and where it takes place in the sun. Nuclear fusion is the joining together of two smaller nuclei to make a larger atom. An example is the fusing together of Hydrogen nuclei to make Helium inside the core of the Sun. As a result of the fusion process, a little bit of mass is lost and is converted into energy in the form of an electro-magnetic wave. 36. Describe what Electro-Magnetic Energy is and identify the different types of electromagnetic energy. Electro-Magnetic Energy is the energy released from the nuclear fusion reactions inside the core of the Sun. This energy travels through the vacuum of space. The amount of energy present relates to the type of radiation. Low Energy Large Wavelength Low frequency High Energy Small Wavelength High Frequency 37. Describe the accepted theory as to the origin of the Universe. The Big Bang Theory is the most widely accepted theory by scientists as to the origin of the universe. The Big Bang theory describes that the Universe started from a single point and all matter that makes up our vast universe was located in this point. Something caused this point to start expanding. Overtime the universe cooled, stardust clumped together forming galaxies and stars. It is space itself that is expanding and pushing the galaxies farther apart. The universe is continuing to expand. 38. Describe what the Red Shift is and why it provides evidence that supports the Big Bang Theory. The Doppler effect is the apparent change of the frequency of a wave as the wave moves toward the observer then away. In order to prove that the universe is expanding, the galaxies must be moving away from each other. The red shift (Doppler effect) provides evidence that the universe is expanding because we see spectral absorption lines in distance starlight continuing to shift to the Red or longer wavelength side of the spectrum.

9 Axis (Y) Name ANSWER KEY Class Table Seat Date THE H-R DIAGRAM Rigel SUPER GIANTS Betelgeuse LUMINOSITY (BRIGHTNESS) Sirius A Sirius B Sun RED GIANTS Aldebaran Alpha Centauri B WHITE DWARFS Axis (X) SURFACE TEMPERATURE SPECTRAL CLASS Color in Box as Well O B A F G K M Answer questions 1 through 4 using the above H-R Diagram 39. Write in the name of each group of stars on the H-R Diagram 40. Label each of the axis on the H-R Diagram 41. Draw in the spectral classes on the bottom of the H-R Diagram 42. Draw in the corresponding spectra in each of the spectral class boxes (Use color Pencils) 43. Place the order of the following stars from youngest (1), middle age (2), oldest (3). 1 Sun 3 Sirius B 2 Betelgeuse

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