Gravity Games Grade Eight

Ohio Standards Connection: Earth & Space Sciences Benchmark A Describe how the positions and motions of the objects in the universe cause predictable and cyclic events. Indicator 2 Explain that gravitational force is the dominant force determining motions in the solar system and in particular keeps the planets in orbit around the sun. Lesson Summary: In this lesson, students will learn how gravity affects the motion of planets in our solar system and beyond. In the pre-assessment, each student will formulate questions about force and motion in the universe and submit them in the form of advice column queries. This allows the teacher to gauge student understanding in a non-threatening manner. The lesson then has student teams participate in three sets of instructional activities, each having a game format. Following each set of games, students will discuss how the activities relate to the role that gravity plays in the universe. Eventually students will explain in their own words how the force of gravity determines the motion of planets. Estimated Duration: Six hours Commentary: Students have learned about gravity, but may not have considered it in the context of planetary motion. This lesson uses a novel "advice column" pre-assessment to motivate students to ask questions and engage them in the content. The game format of this lesson helps keep the students engaged, while modeling the effects of gravity on celestial objects. Pre-Assessment: Suggest to students that it is difficult to study or understand forces and motion in space, even in our solar system, because most of us cannot leave the surface of the Earth. However, some of these forces impact our lives daily and are usually taken for granted. A good example is the force of gravity, and how it holds us to the Earth and how it holds the solar system together. Introduce students to the advice column form of asking questions or requesting help from a trained specialist using a pseudonym. The specialist for this activity will be a character named Albert (a.k.a. Albert Einstein) who knows everything possible about motion and forces in the solar system and the universe. 1

Ask each student or student pair to write an Ask Albert letter asking a question about the mysterious forces that control the solar system and universe. The question should be signed with a pseudonym so nobody knows who wrote each letter (students names should be included on the letters for record keeping only). The following class period, read a selection of the Ask Albert letters in class, using only the pseudonym. Give students an opportunity to pose possible responses to the questions or ways to investigate the questions. Keep a record of all suggested answers to be verified at a later date. These letters can be reviewed from time to time, especially when research provides accurate answers. Scoring Guidelines: This pre-assessment should provide the teacher with students conceptions or misconceptions about the role gravity plays in the motion of the planets. On the chance no student asks questions related to gravity, then teacher-generated questions can be substituted. Also write these questions under a pseudonym to give the impression they were also generated by the students. In addition to providing knowledge about student comprehension, this activity can trigger the students interest in the topic and provide a bridge between the instructional activities and the indicator. The questions that students pose should involve either force or motion in the universe and should use the term gravity in the correct context. Following is a list of acceptable questions, which could also be substituted by the teacher if not included in the Ask Albert letters. What force keeps the planets in their orbits? How does gravity work? Why don t the planets crash into the sun? Why don t the planets fly out into space? Why doesn t gravity of the sun or moon affect us? Are there things in space not attracted by gravity? Note questions that indicate a misunderstanding of the general concept of gravity. The following questions suggest that the student doesn t understand the general concept of gravity. Why is gravity stronger at the North and South Pole than the Equator? How much less do we weigh when the sun is shining on us? Could gravity pull us to the center of the Earth? Post-Assessment: Print and distribute copies of Attachment A, Post-Assessment. Each student will complete a writing/graphic evaluation. Scoring Guideline: See Attachment B, Post-Assessment Answers, to guide scoring of student work. 2

Instructional Procedures: Gravity Games Grade Eight Instructional Tip: Students will be involved in three sets of instructional activities presented in a game format. These activities will help students answer the Pre-Assessment Ask Albert questions, and reach a better understanding about gravity and the hold it has on objects throughout the universe. Students will participate in teams of three to five students. You may keep track of which teams win the events, or may choose not to keep track if competition is not desired. You may want to demonstrate each event before the students attempt them. Activity Set One: Sports Games 1. Select an outdoor site or a large indoor site for the Sports Games. 2. See Attachment C, Planetary Orbit Race, for detailed instructions of the first event. Use the attachment as a handout for students to provide directions and help them record their results. 3. Have one team member represent the sun and hold one end of a 12 meter rope. 4. Instruct another team member to hold the other end of the rope and race around in a circle while keeping the rope tight. This team member represents a planet orbiting the sun and the rope represents the force of gravity. 5. Have the student teams record the time it takes for each student to run orbits around the sun and have each student record their times on their worksheet. 6. Have students repeat the exercise using different lengths of rope, as directed on Attachment C. Instructional Tip: Students holding each end of the rope need to pull with enough strength that they can feel the pull while not pulling the rope out of the other student s hands which could cause an injury. Very likely the further they stand from each other, the more difficulty they will experience controlling the rope. In the follow-up discussion, this problem can be compared to the weakening force of gravity due to distance. 7. See Attachment D, Comet Time Trials, for detailed instructions for the second Sports Game event. Use the attachment as a handout for students to provide directions and help them record their results. 8. Have one team member represent the sun and another team member represent the comet. Have the "comet" stand facing the sun 12 meters away. 9. Instruct the comet to race in an elliptical orbit twice around the sun, each orbiting in the same period of time. 10. Remind student teams to time the orbits of their team members, and remind the "comets" to enter their times on their worksheets. 11. See Attachment E, Weightless Ball, for detailed instructions for the third Sports Game event. Use the attachment as a handout for students, to provide directions and help them record their results. 3

12. Following the instructions on the handouts, instruct each team to throw a beach ball in such a manner that it stays aloft the longest period of time. 13. Remind students to time their events and record their times on their worksheets. 14. See Attachment F, Centrifugal Throw, for detailed instructions of the fourth Sports Game event. Use the attachment as a handout for students to provide directions and help them record their results 15. Prepare a foam playground ball attached to a rope one meter long. 16. Instruct students on each team to take turns trying to throw the rope and ball combination the farthest. Show students how to hold the rope and swing the ball around in a circular path, and then release it so that the ball travels the greatest distance. 17. Remind teams to measure the distances thrown by each team member, and to write these distances on their worksheets. 18. During a subsequent class period, you may recognize teams with the best scores. 19. Lead discussions of how each event relates to the role gravity plays in controlling movement of celestial bodies throughout the solar system. For example, use results of Planetary Orbit Race to show how distance affects revolution time for planets, and how this revolution time would be affected if the force of gravity increased or decreased. Furthermore, the students will find the rope easier to control as they move closer to each other, which is comparable to the stronger pull of gravity on the planets closer to the sun. Discuss how Comet Time Trials mimicked the consistency of gravitation force and the predictability of movement controlled by gravity. The shape of an orbital path could by analyzed, and the terms perigee and apogee introduced. Discuss the Weightless Ball game, and what is meant by weightlessness or microgravity. Challenge students to consider how it affects objects and people traveling through space. Use a discussion of the Centrifugal Throw game to help students understand the forces that are resisting gravitational pull and what might happen if gravity did not exist. In the solar system, inertia of each moving planet prevents the planet from falling into the sun. Activity Set Two: Search Games 20. Select four reference sources that students can use to find information about universal gravitation. 21. Devise four questions about universal gravitation that students can answer using the resources. For example, you can have your class use the following resources to answer these questions: Internet Find the formula for universal gravitation and what each symbol represents. (This formula may seem abstract to the students; however, discussing what each symbol represents and how they are computed to give the force of gravity a numerical value, can help students understand the dominance of this force.) Dictionary Find the following definitions as they relate to universal gravitation: galaxy, nebula, binary stars and black hole. Science text Find the relationship between gravity and the mass of the planet or star. 4

Library Find the difference between terminal velocity and escape velocity as they relate to gravitational force. 22. Divide students into teams. These can be the same teams used in preceding exercises, or you can make new teams. 23. Instruct the teams to attempt to find answers to your questions using information from each of these resources in the fastest time. Teams can elect to divide and conquer to find the answers or work together on each. 24. During a subsequent class period, verify the students' research in an open question/answer section or discussion. Focus the discussion on how this information relates to the study of gravity and if additional Ask Albert questions have been answered. 25. You may recognize teams with the best time scores and give them an opportunity to explain their success, or you may choose to proceed without team recognition. Activity Set Three: Gravity Game Instructional Tip: As a learning tool this activity may be more useful helping students review concepts learned from the previous sets of activities and prepare for the post-assessment. The more often the game is played, the more students should remember. There are questions in the game that have to do with aspects of gravity that are not included in the indicator. These questions could provide a bridge to related topics of discovery. 26. Cut out game cards using Attachment G, Gravity Game Questions. Read the rules of the game on Attachment H, Gravity Game Rules. Share these rules with the class verbally, or as a handout. 27. Arrange students into teams, or keep the teams used in previous events. 28. Draw questions from the pile of cards and read questions to student teams. 29. Have teams take turns answering questions. Following the directions on Attachment H, each correctly answered question is worth points, while any missed questions will deduct those points from a team s score. See Attachment I, Gravity Game Answers, for answers to the questions. 30. Continue play as point totals accrue. 31. When all questions have been answered, the team with the highest point total wins the contest. 32. Proceed to the post-assessment. Differentiated Instructional Support: Instruction is differentiated according to learner needs to help all learners either meet the intent of the specified indicator(s) or, if the indicator is already met, to advance beyond the specified indicator(s). You may have to adjust the post-assessment to better meet the needs of some students, including reading or rewording the questions to the students, scribing in responses for the student, or providing the student with a limited selection of possible answers. 5

During the Search Games, students research selected topics using different reference sources. This allows students with different ability levels an opportunity to participate without the appearance that one type of reference source is easier or more challenging than the other. You may have to advise teams, suggesting which team member works with which reference source. Searching for definitions in a dictionary or using the index of a science text tends to be easier than the Internet or library search. Extensions: You could use the Gravity Game as an alternate extension activity, although it does provide a good review for students, and could alert you if there are topics that need more explanation. Have students design their own sports games to simulate the effects of gravity on celestial bodies. Homework Options and Home Connections: Have students identify household chores that would be easier/harder if gravity increased or decreased. Have students look for objects or organisms around the home that seem to defy gravity (e.g., helium balloons, airborne seeds, flying birds and insects) and explain how they are able to float above the earth. Materials and Resources: The inclusion of a specific resource in any lesson formulated by the Ohio Department of Education should not be interpreted as an endorsement of that particular resource, or any of its contents, by the Ohio Department of Education. The Ohio Department of Education does not endorse any particular resource. The Web addresses listed are for a given site s main page, therefore, it may be necessary to search within that site to find the specific information required for a given lesson. Please note that information published on the Internet changes over time, therefore the links provided may no longer contain the specific information related to a given lesson. Teachers are advised to preview all sites before using them with students. For the teacher: 12 meter rope (or string), meter stick (or metric tape measure), stop watch, beach ball, foam ball w/rope, game cards. For the students: 12 meter rope (or string), meter stick (or metric tape measure), stop watch, beach ball, foam ball w/rope. Vocabulary: apogee binary stars black hole escape velocity galaxy gravity 6

mass wasting microgravity neap tide nebula Newton orbit perigee pulsar terminal velocity Technology Connections: An Internet site containing exhaustive information about our universe is maintained by the National Aeronautics and Space Administration, at www.nasa.gov Research Connections: Marzano, R. et al. Classroom Instruction that Works: Research-Based Strategies for Increasing Student Achievement. Alexandria: Association for Supervision and Curriculum Development, 2001. Identifying similarities and differences enhances students understanding of, and ability to use, knowledge. This process includes comparing, classifying, creating metaphors and creating analogies and may involve the following: Presenting students with explicit guidance in identifying similarities and differences. Asking students to independently identify similarities and differences. Representing similarities and differences in graphic or symbolic form. Nonlinguistic representations help students think about and recall knowledge. This includes the following: Creating graphic representations (organizers); Making physical models; Generating mental pictures; Drawing pictures and pictographs; Engaging in kinesthetic activity. Cooperative learning groups have a powerful effect on student learning. This type of grouping includes the following elements: Positive interdependence; Face-to-face promotive interaction; Individual and group accountability; Interpersonal and small group skills; Group processing. 7

General Tips: Use only pseudonyms when reading the Ask Albert questions to the class. Although not all team members are necessary for each event, all team members should participate in sports games. Depending on how much adult assistance is available, each event of Sports Games could be conducted alone or in a team rotation. Weightless Ball should be conducted away from buildings and/or areas that are off-limits. Centrifugal Throw would take less time if the area was already marked for distance, and if team members are used to mark where the ball lands each time. This event should also be conducted away from buildings or areas that are off-limits. As noted in the selection of reference sources for the Search Game, you may have to adjust references according to what is available. The topics that are researched should not be changed since these are concepts directly connected to the indicator and benchmark. There are ways of directly experiencing the effects of the force of gravity in the solar system, either by observing the tides (possibly on vacation) or observing the change in position of the planets in the night sky. When covering indicators under the Physical Science Standard, establish connections between gravitational force and Newton s Laws of Motion and conservation of energy. The Gravity Game should be played in teams so that team members have an opportunity to converse before responding with their answer or before deciding to use one of the cards. Attachments: Attachment A, Post-Assessment Attachment B, Post-Assessment Answers Attachment C, Planetary Orbit Race Attachment D, Comet Time Trials Attachment E, Weightless Ball Attachment F, Centrifugal Throw Attachment G, Gravity Game Questions Attachment H, Gravity Game Rules Attachment I, Gravity Game Answers 8

Attachment A Post-Assessment Short Answer If a rock is released from your hand, it falls to the ground because of a force called gravity. When a satellite is launched from the Earth s surface and continues to circle the Earth, it is falling around the Earth because of a force called gravity. Explain the role of gravity in each of the following relationships. 1. The moon and the Earth - 2. The planets and the sun - Drawing Following is a diagram of the solar system, showing the sun and the first three planets. Please note that the sun and planets are not drawn to scale. Venus (67,000,000 miles) Sun Mercury (33,000,000 miles) Earth (93,000,000 miles) On the following pages you ll find that this graphic has been copied three times except for the locations of the three planets. You are being asked to predict and draw the locations of the planets based on special conditions. 9

Attachment A (continued) Post-Assessment Diagram #1 - Indicate the orbit of each planet if the force of gravity between the sun and planets increased. Sun Diagram #2 - Indicate the orbit of each planet if the force of gravity between the Sun and planets decreased. Sun 10

Attachment A (continued) Post-Assessment Diagram #3 - Indicate the orbit of each planet if there was no gravity between the sun and planets Sun Sentence Completion Add a word or words at the end of the second sentence to substitute for the underlined word used in the first sentence so that both sentences have the same meaning: The planet remains in orbit around the sun because of gravity. The planet remains in orbit around the sun because. 11

Attachment B Post-Assessment Answers Possible correct responses for the post-assessment are written below. Short Answer 1. The role of gravity between the moon and Earth Gravity holds the moon in orbit around the Earth. Gravitational pull of the moon causes the tides. Gravity causes the moon to fall around the Earth. Gravity causes an attraction between the moon and Earth. 2. The role of gravity between the sun and planets Gravity holds the planets in orbit around the sun. Gravity prevents the planets from flying out into space. Gravity causes the planets to fall around the sun. Gravity causes an attraction between the planets and sun. Drawing Diagram #1 Force of gravity has increased. A point should be given for each planet s orbit that is drawn closer to the sun than shown in the example. Diagram #2 Force of gravity has decreased. A point should be given for each planet s orbit that is further from the sun than shown in the example. Diagram #3 No force of gravity A point should be given for each planet where no orbital path is drawn around the sun. Showing no planets also is correct. Sentence Completion The planet remains in orbit around the sun because of a force that holds it there. because there is a force that attracts one to the other. because they are held there by a dominant force. 12

Materials: 12m rope (or string) meter stick (or tape measure) stop watch Gravity Games Grade Eight Attachment C Planetary Orbit Race Directions: 1. One member of the team will stand in an open area. This student will represent the sun. He/she will hold one end of the 12 meter rope. 2. Another member of the team will hold the other end of the rope standing 12 meters away. This team member will represent a planet that is orbiting the sun. The rope will represent the force of gravity. 3. The team member representing the planet will pull the rope tightly and run as fast as possible in a circular path around the "sun," always pulling tightly on the rope. The student representing the sun will have to turn slowly in place to prevent the rope from twisting around their body. 4. A third team member will time the team member representing the planet as he/she races one orbit around the sun. Record this time in the space below. 5. The rope will now be shortened to 6 meters. The team member representing the sun will hold the excess rope. 6. The team member representing the planet, while tightly pulling on the rope, will race one orbit around the sun. The student representing the sun will slowly turn in place so the rope won t become tangled. 7. The student recording time will record the time for one orbit in the indicated space below. 8. The team member representing the sun will shorten the rope to only 3 meters. 9. The team member representing the planet will again race in an orbit around the sun. The student representing the sun will have to turn a little quicker this time so that the rope won t become tangled. 10. The timer will again record the running time in the space indicated. Time - 12 meter rope Time - 6 meter rope Time - 3 meter rope 13

Materials: meter stick (or tape measure) stop watch Gravity Games Grade Eight Attachment D Comet Time Trials Directions: 1. One member of the team will stand in an open area. This student will represent the sun. 2. Another team member will stand 12 meters away facing the sun. This student will represent a comet that orbits the sun. 3. The student representing the comet will race toward the sun, rounding the person representing the sun as close as possible without touching that person, and then back to where the comet was first standing. 4. A third member of the team will record the time it took the comet to make one orbit. 5. The student representing the comet will race around the sun once again; attempting to orbit the sun in the exact same time it took the first time. 6. The same student as before will record the time, but then will subtract the two times to determine how closely the second time matched the first time. Time - 1 st Orbit Time - 2 nd Orbit Time Difference 14

Materials: beach ball stop watch Attachment E Weightless Ball Directions: 1. Each member of the team will take a turn throwing a beach ball so that it stays in the air the longest period of time. 2. Each student s throw will be timed from the moment it leaves his/her hand until the ball touches the ground. In the event the ball strikes an obstacle before landing on the ground, that individual will be required to throw again. 3. Adding together the time periods of all team members, and then dividing by the number of students on the team will determine the team s average time-aloft. Time - 1 st team member Time - 2 nd team member Time - 3 rd team member Time - 4 th team member Total team time - Divide by number of members on the team Average team time - 15

Attachment F Centrifugal Throw Materials: meter stick (or tape measure) foam playground ball attached to rope (1 meter) Directions: 1. One team member will be swinging and releasing the ball/rope in such a manner that the ball will travel the greatest distance. This team member will be attempting this throw three times. 2. Other team member(s) will assist measuring and recording the distance in the space provided. 3. The Best Distance is the greatest distance of the three trials. Distance - 1 st Trial Distance - 2 nd Trial Distance - 3 rd Trial Best Distance - 16

Attachment G Gravity Game Questions 1. What type of measurement is used to measure the gravity attraction on an object? + What unit of measure is used to label gravitational force? - What is the metric unit of measure for mass? 2. Because planets are closer to the sun at one part of the orbit and further from the sun on another part of the orbit, what is the basic shape of the orbit of a planet around the sun? + What is the closest approach of a planet to the sun called? - What time period is one orbit of the Earth around the sun? 3. What force causes comets to orbit around the sun? + What is the name of one comet that orbits our sun? - What is the comet s vapor trail called? 4. What special name is given to stars located close enough to each other so that one star orbits the other? + What special name is given to spinning stars that transmit radio waves? - What family relation is one of two orbiting stars said to be of the other? 5. What celestial body affects the ocean tides on Earth? + What is the annual high tide called? - During what phase of the moon would tides be higher? 6. What special name is given to the gas and dust cloud that is pulled together by gravity to form a new star? + What force triggers the life of a new star? - What happens to the temperature of this star cloud, as the particles are pulled closer together? 7. Name a sport that is affected by gravity. + Name a sport that is not affected directly by gravity. - Name a sport that requires jumping to be successful. 8. Which part of the water cycle is affected most by gravity? + What is the scientific name for all erosion caused by gravity? - What name is given to soil and rock quickly moving downhill due to gravity? 9. What condition is experienced when there is no gravity? + Since it is impossible to have absolutely no gravity, what special name is given for very small amounts of gravitational pull? - What letter do scientists use to indicate the comparative value in Earth s gravity? 17

Attachment G (continued) Gravity Game Questions 10. If the force of gravity increased, how would the orbit distance of planets be affected? + For the planets, what force counter-effects the pull of gravity? - If gravity decreased, how would the revolution time of planets be affected? 11. Name a daily task that would be easier to do without gravity. + Name a daily task that would be unaffected by gravity. - Name a daily task that would be harder to do without gravity. 12. Gravity affects the shape of galaxies; name one of the shapes. + Name a galaxy other than the one the Earth is located. - Name the galaxy where the Earth is located. 13. Which planet of our solar system has the lowest gravitational pull for objects on that planet? + How does a planets size effect the pull of gravity on that planet? - On which planet would an individual weigh the most? 14. The formula for universal gravitational force is F = G ( M x m )/ d x d. Applying this formula to the gravity attraction of the sun and Earth, what does the symbol M represent? + What does the symbol G represent? - What does the symbol d represent? 15. If the force of gravity decreased, how would the orbit distance of planets be affected? + How would the orbit of the planets be affected if there was no gravity attraction? - If the force of gravity increased, how would the revolution time of planets be affected? 16. What is the scientific name given to an artificial body or object that orbits a larger body in space? + What are the many small bodies or objects in space that orbit the sun between the orbits of Mars and Jupiter? - What name is given to the natural body that orbits a planet? 17. What is the scientific name given to the speed an object needs to reach in order to overcome the pull of gravity on a planet? + What is the speed in miles/hour to overcome Earth s gravity? - What kind of vehicle has the power needed to overcome gravitational force? 18. What special term is given to the velocity of a falling object when it can no longer accelerate? + How many meters/second faster does an object accelerate for every second it falls? - On Earth, what force slows a falling object? 18

Attachment G (continued) Gravity Game Questions 19. How does the orbit time period change for planets further and further from the sun? + What special term is used to describe one planet s position in orbit lining up with another planet s position in its orbit? - Which planet has the shortest year? 20. What special name is given to the body in space that has the strongest gravitational attraction? + What kind of radiation increases near this kind of space body? - Gravitational force is so strong on this stellar body that this kind of radiant energy cannot escape its attraction? 19

Attachment H Gravity Game Rules Basic instructions 1. Arrange students into teams, and then arrange teams in a large circle. 2. Before the game begins, give each team two Gravity-Up cards, two Gravity-Down cards, and one No-Gravity card. 3. Starting with any team in the room, draw a Gravity Game Question from a deck made from Attachment G. 4. Ask the question to the team, and award points if they answer the question correctly, or subtract that number of points from their score if they answer incorrectly. 5. Order of play moves in a clockwise direction, unless the order is reversed using Gravity- Up or Gravity-Down cards (see next section). 6. Continue this process through all teams until all questions have been asked. 7. The team with the highest point total at the end of the game wins. Significance of Gravity-Up, Gravity-Down and No-Gravity cards When it is a team s turn to play and before the question has been asked, they can use a Gravity-Up card or a Gravity-Down card to send that question to another team. A Gravity-Up card will send the question to the next team in the clockwise direction, and a Gravity-Down card will send the question to the next team in the counterclockwise direction. Play will proceed in that direction. If a team receives an additional question because another team has used a Gravity-Up card or a Gravity-Down card, that team can send the question back or on to another team by using one of their own Gravity-Up or Gravity-Down cards. When it is a team s turn to play and after the question has been asked, the team can use a Gravity-Up card to get a more difficult related question that is worth more points or use a Gravity-Down card to get an easier related question worth fewer points. These are indicated by a plus and minus sign respectively, on the game card. A team can change the level of the question, even if it was passed to them from another team. Only one Gravity-Up card or Gravity-Down card can be used during a turn. Any Gravity-Up cards and/or Gravity-Down cards that a team retains at the end of the game will also hold point value. To completely eliminate a question or a turn, a team can use a No Gravity card. This card can be used at any time, even if a Gravity-Up card or Gravity-Down card has already been used. A No-Gravity card has no value if held to the end of the game. Remember to collect all cards at the end of the game. Scoring A correct response to the main questions is worth 10 points each. Gravity-Up responses are worth 15 points and Gravity-Down responses are worth 5 points. Any incorrect responses deduct the same amount of points from the team score. Any Gravity-Down cards retained at the end of the game are worth 15 points, and any Gravity-Up cards are worth 5 points. The No-Gravity card has no value. 20

1. weight (also mass or force) + Newton - Gram or kilogram 2. ellipse or elliptical + perigee or perihelion - year 3. gravity + Halley s Comet, Encke s Comet - tail 4. binary stars, double stars + pulsars - sister 5. moon or sun + spring tide or neap tide - full moon 6. nebula + thermonuclear force - increases 7. baseball, basketball, golf, football, etc. + boxing, bowling, etc. - basketball, high jump, etc. 8. precipitation + mass-wasting - avalanche or landslide 9. weightlessness + micro-gravity - G 10. decrease + inertia - increase Gravity Games Grade Eight Attachment I Gravity Game Answers 21

11. clean ceiling, change light bulb, etc. + brushing teeth, shaving, etc. - wash dishes, water plants, etc. 12. spiral, elliptical, irregular + Andromeda - Milky Way 13. Pluto + larger size- greater pull - Jupiter 14. mass of the sun + gravity constant - distance 15. increase + no orbit path - decrease 16. satellite + asteroids - moon 17. escape velocity + 25,000 m/hr - rocket 18. terminal velocity + 9.8 m/s 2 - air pressure 19. increase + conjunction - Mercury 20. black hole + X-ray - light or other radiant energy Gravity Games Grade Eight 22