# 1. S/Q, p 3-80 to p 3-81 2. Activity #5, except Bending a stream of water, p 3-84 to p 3-85 3. Discussion: Explaining a - PowerPoint PPT Presentation

1. S/Q, p 3-80 to p 3-81 2. Activity #5, except Bending a stream of water, p 3-84 to p 3-85 3. Discussion: Explaining a

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1. S/Q, p 3-80 to p 3-81 2. Activity #5, except Bending a stream of water, p 3-84 to p 3-85 3. Discussion: Explaining a

## 1. S/Q, p 3-80 to p 3-81 2. Activity #5, except Bending a stream of water, p 3-84 to p 3-85 3. Discussion: Explaining a

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1. Plan for today’s class 1. S/Q, p 3-80 to p 3-81 2. Activity #5, except Bending a stream of water, p 3-84 to p 3-85 3. Discussion: Explaining a ball toss, p 3-86 to 3-91 4. Change the group members 5. Chapter 4, Activity 1, revisit the table on p 3-6 6. Discuss you results with other group p 4-6 to 4-9 group 1&2, group 3&4, group 5,6&7 7. S/Q, p 4-13 8. Activity 2 During the spring break, try to be aware of any phenomenon that related to gravitational force. We will have “show and tell” at the beginning of Mar. 23.

2. S/Q, p 3-80 to p 3-81 S1: Does the strength of the gravitational force of the Earth pulling an object toward the ground depend on the object’s mass? What evidence supports your answer? (#3) S2: What other force, apart from the gravitational force of the Earth, acts on falling objects? What types of objects are affected most by this force? (#4)

3. S3: If the force of air resistance is negligible, does the rate at which a falling object’s speed increases depend on its mass? Why do you think this is? (#5) S4: When a skydiver jumps out of an aircraft he speeds up at first but eventually, after he has fallen for awhile, his speed actually becomes constant. (This is before he opens his parachute.) Use your ideas about forces acting on the skydiver as he falls to write a scientific explanation for why this happens. (#6)

4. Explanation: Why does a skydiver speed up at first but eventually fall at a constant speed? Describe the situation using a diagram: (Hint: You may wish to draw two or three force diagrams for this explanation.) All groups on the white board

5. Plan for today’s class 1. S/Q, p 3-80 to p 3-81 2. Activity #5, except Bending a stream of water, p 3-84 to p 3-85 3. Discussion: Explaining a ball toss, p 3-86 to 3-91 Let us start this discussion at 1:25 PM 4. Change the group members 5. Chapter 4, Activity 1, revisit the table on p 3-6 6. Discuss you results with other group p 4-6 to 4-9 group 1&2, group 3&4, group 5,6&7 7. S/Q, p 4-13 8. Activity 2 During the spring break, try to be aware of any phenomenon that related to gravitational force. We will have “show and tell” at the beginning of Mar. 23.

6. Explaining a ball toss, p 3-86 to p 3-91 During the toss While you are tossing the ball upward, before the ball leaves your hand, does the gravitational force of the Earth act on the ball? Does the hand exert a force on the ball? Explain your reasoning. (#7) Are the forces acting on the ball balanced or unbalanced? How do you know? (#1)

7. Why does the ball start to move upward when you toss it? The force diagram (#2)

8. Ball rising upward after the toss Does the gravitational force of the Earth act on the ball while it is rising upward after is has left your hand? Does the hand exert a force on the ball? Explain your reasoning. (#3)

9. Why does the ball slow down as it is moving upward, and eventually start to fall back down, after you toss it? Describe the situation using a diagram: (#4)

10. Narrative: (#5) During the toss, the force of the hand is transferred to the ball. But without the hand still pushing it, this force gradually runs our as the ball rises. As the force runs our, the speed of the ball decreases as it rises. When this force runs out completely the gravitational force of the Earth takes over and the ball begins to fall back down.

11. Catching the ball Which way is the ball moving before you catch it? (#6) While you are catching the ball, does your hand exert a Force on it? Does the Earth exert a gravitational force while you are catching it also? How do you know? (#7) After you have caught it, the ball, it is at rest. What must Have happened to its speed while you were catching it? (#1)

12. In order for this change in speed to take place, would the combination of forces acting on the ball need to be balanced or unbalanced? If unbalanced, in which direction would the strongest force need to be acting- Upward or Downward? (#2)

13. Why does the ball slow down while you are catching it? Describe the interaction using a diagram: (#3)

14. Plan for today’s class 1. S/Q, p 3-80 to p 3-81 2. Activity #5, except Bending a stream of water, p 3-84 to p 3-85 3. Discussion: Explaining a ball toss, p 3-86 to 3-91 4. Change the group members 5. Chapter 4, Activity 1, revisit the table on p 3-6 6. Discuss you results with other group p 4-6 to 4-9 group 1&2, group 3&4, group 5,6&7 7. S/Q, p 4-13 8. Activity 2 During the spring break, try to be aware of any phenomenon that related to gravitational force. We will have “show and tell” at the beginning of Mar. 23.

15. Plan for today’s class 1. S/Q, p 3-80 to p 3-81 2. Activity #5, except Bending a stream of water, p 3-84 to p 3-85 3. Discussion: Explaining a ball toss, p 3-86 to 3-91 4. Break, Change the group members, end at 2:07 PM 5. Chapter 4, Activity 1, revisit the table on p 3-6 6. Discuss you results with other group p 4-6 to 4-9 group 1&2, group 3&4, group 5,6&7 7. S/Q, p 4-13 8. Activity 2 During the spring break, try to be aware of any phenomenon that related to gravitational force. We will have “show and tell” at the beginning of Mar. 23.

16. All groups

17. Plan for today’s class 1. S/Q, p 3-80 to p 3-81 2. Activity #5, except Bending a stream of water, p 3-84 to p 3-85 3. Discussion: Explaining a ball toss, p 3-86 to 3-91 4. Break, Change the group members, end at 2:07 PM 5. Chapter 4, Activity 1, revisit the table on p 3-6 6. Discuss you results with other group p 4-6 to 4-9 group 1&2, group 3&4, group 5,6&7 7. S/Q, p 4-13, start at 3:00 PM 8. Activity 2 During the spring break, try to be aware of any phenomenon that related to gravitational force. We will have “show and tell” at the beginning of Mar. 23.

18. S/Q, p 4-13 S1: Do both ends of a rubbed nail (magnet) behave similarly or differently when interacting with another rubbed nail? How do you know? (#4) S2: In what way does a rubbed nail seem to be different from an unrubbed nail when interacting with another rubbed nail? (#5) S3: In the initial ideas section of this activity you were asked what material you think magnets are made from. How would you answer that question now? What evidence supports your current answer? (#6)

19. Plan for today’s class 1. Activity 3, p2-65 2. Activity 4, p2-69 to 2-72 3. S/Q, p 2-71 to 2-72, will start at 1:10 4. Activity 5 5. Initial Ideas P2-75 to 2-7, will start at 1:35 6. Break 7. Demonstrations will start at 2:05 8. S/Q, p 2-84 to 2-86 will start at 3:00 9. Activity 6 Please throw away the bad markers, clean your white board, turn off the monitor.