1. Gravity

2. 10/5 Gravitational constant = 6.66*10-11
What comes to mind when you hear the word gravity?
Convert the following to scientific notation
Distance from Sun: 92,960,000 miles ____
Estimated Age of universe – 14,000,000,000
Convert the following to standard form
Speed of light = 9.0 * 108 m/s
Gravitational constant = 6.66*10-11

3. Multiplying in Scientific Notation

4. Multiplying… The general format for multiplying is as follows…
(N x 10x)(M x 10y) = (N)(M) x 10x+y
First multiply the N and M numbers together and express an answer.
Secondly multiply the exponential parts together by adding the exponents together.

5. Multiplying…
Finally multiply the two results for the final answer.
(2.41 x 104)(3.09 x 102)
2.41 x 3.09 = 7.45
4 + 2 = 6
7.45 x 106

6. Dividing in Scientific Notation

7. Dividing… The general format for dividing is as follows…
(N x 10x)/(M x 10y) = (N/M) x 10x-y
First divide the N number by the M number and express as an answer.
Secondly divide the exponential parts by subtracting the exponent from the exponent in the upper number.

8. Dividing…
Finally multiply the two results together to get the final answer.
(4.89 x 107)/(2.74 x 104)
4.89 / 2.74 = 1.78
7 – 4 = 3
1.78 x 103

9. 11/22
1. How do you weigh an elephant using only a board, yourself and a fulcrum?
2. Why do you weigh less on a mountain? (universal gravitation)

10. 10/7 1. What factors does the force of gravity depend on?
2. How did newton change the way we see gravity?
3. What is the difference between weight and mass?

11. 13.1 The Falling Apple
Newton reasoned that the moon is falling toward Earth for the same reason an apple falls from a tree—they are both pulled by Earth’s gravity.

12. 3/7 What comes to mind when you think of newtons laws? 1. inertia
2. F=M*A
3. Action reaction

13. 13.1 The Falling Apple
Newton understood the concept of inertia developed earlier by Galileo.
He knew that without an outside force, moving objects continue to move at constant speed in a straight line.
He knew that if an object undergoes a change in speed or direction, then a force is responsible.

14. 13.2 The Falling Moon
If the moon did not fall, it would follow a straight-line path.

15. 13.2 The Falling Moon
This original drawing by Isaac Newton shows how a projectile fired fast enough would fall around Earth and become an Earth satellite.

16. 13.2 The Falling Moon
Tangential velocity is the “sideways” velocity—the component of velocity perpendicular to the pull of gravity.

17. 13.2 The Falling Moon
If the force that pulls apples off trees also pulls the moon into orbit, the circle of the moon’s orbit should fall 1.4 mm below a point along the straight line where the moon would otherwise be one second later.

18. 13.3 The Falling Earth
Newton’s theory of gravity confirmed the Copernican theory of the solar system.
Earth orbits the sun like the moon orbits the earth, constantly being pulled in, while tangential velocity is keeping the object in orbit.

19. Universal Gravitation
Gravity acts everywhere in the universe. The force that causes an apple to fall is the same force that acts on the moon.
What factors does gravity depend on

20. 1. What are the two things that cause the moon to orbit the earth?
2. What would happen to your weight, if your radius from the center of the Earth doubled?

21. 13.4 Newton’s Law of Universal Gravitation
Newton’s law of universal gravitation states that every object attracts every other object with a force that for any two objects is directly proportional to the mass of each object.
Newton deduced that the force decreases as the square of the distance between the centers of mass of the objects increases.

22. 13.4 Newton’s Law of Universal Gravitation
The force of gravity between objects depends on the distance between their centers of mass.

23. 13.4 Newton’s Law of Universal Gravitation
Your weight is less at the top of a mountain because you are farther from the center of Earth.

24. 13.4 Newton’s Law of Universal Gravitation
The Universal Gravitational Constant, G
The law of universal gravitation can be expressed as an exact equation when a proportionality constant is introduced.
The universal gravitational constant, G, in the equation for universal gravitation describes the strength of gravity.

25. 13.4 Newton’s Law of Universal Gravitation
Philipp von Jolly developed a method of measuring the attraction between two masses.

26. 13.4 Newton’s Law of Universal Gravitation
A simpler method was developed by Philipp von Jolly.
He attached a spherical flask of mercury to one arm of a sensitive balance.
A 6-ton lead sphere was rolled beneath the mercury flask.
The flask was pulled slightly downward.
The gravitational force F, between the lead mass and the mercury, was equal to the weight that had to be placed on the opposite end of the balance to restore equilibrium.
F, m1, m2, and d were all known, so the ratio G was calculated:

27. 13.5 Gravity and Distance: The Inverse-Square Law
Butter spray travels outward from the nozzle in straight lines. Like gravity, the “strength” of the spray obeys an inverse-square law.

28. 13.5 Gravity and Distance: The Inverse-Square Law
This law applies to the weakening of gravity with distance.
It also applies to all cases where the effect from a localized source spreads evenly throughout the surrounding space.
Examples are light, radiation, and sound.

29. 13.5 Gravity and Distance: The Inverse-Square Law
Gravitational force is plotted versus distance from Earth’s center.

30. 13.6 Gravitational Field
Field lines represent the gravitational field about Earth.

31. 13.7 Gravitational Field Inside a Planet
As you fall into a hole bored through Earth, your acceleration diminishes. The pull of the mass above you partly cancels the pull below.

32. 13.9 Ocean Tides
Newton showed that the ocean tides are caused by differences in the gravitational pull of the moon on opposite sides of Earth.

33. 13.9 Ocean Tides
This difference in pulls across Earth slightly elongates it.
The oceans bulge out about 1 meter on average, on opposite sides of Earth.
Because Earth spins once per day, a fixed point on Earth passes beneath both of these bulges each day, producing two sets of ocean tides per day—two high tides and two low tides.

34. 13.9 Ocean Tides
The two tidal bulges remain relatively fixed with respect to the moon while Earth spins daily beneath them.

35. 13.9 Ocean Tides
When the attractions of the sun and the moon are at right angles to each other (at the time of a half moon), neap tides occur.

36. 13.4 Newton’s Law of Universal Gravitation
The Universal Gravitational Constant, G
What happens to F if
One mass is half as much
Both masses are twice as much.
The distance is tripled
Hint, substitute a one for every thing then do what the question is asking you to do.

37. 13.10 Black Holes
The size of the sun is the result of a “tug of war” between two opposing processes: nuclear fusion and gravitational contraction.

38. 13.10 Black Holes
When a massive star collapses into a black hole, there is no change in the gravitational field at any point beyond the original radius of the star.
You will learn later that our some never becomes a blackhole…sorry

39. What would happen to the earth if the sun collapsed into a black hole?
Use the gravity equation to explain why a black hole is so powerful.
Use the gravity equation to explain why a black hole is so powerful.
A black hole is a place in space where gravity pulls so much that even light can not get out.
The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.

40. 10 / 8 - Today we will be collecting data for the next CER
If you were plotting mass and force, which would be the dependent variable and which would be the independent variable?
Which axis would you place them on?

41. Gravitational force dependent variable
Mass independent variable

42. Copy the following tables in your science notebook.
After completing the first table,
Mass 1
Mass 2 (kg)
Force (10-11N) 30
distance
force

43. How to create a graph on microsoft excell
mass 1
force 10
3.00E-10 20
1.05E-09 30
1.57E-09 40
2.09E-09 50
2.62E-09 60
3.14E-09 70
3.66E-09 80
4.19E-09 90
4.71E-09
100
5.23E-09
How to create a graph on microsoft excell

44. How to make a line graph on Microsoft excel
Type the horizontal independent variable values in the left hand column,
Type the dependent y-values in the right column
Highlight numbers
Go to insert – scatter – smooth column
Enter in Labels and titles
- left click on line – click add trendline
Click on display equation on chart, and add r-square value

45. Which direction does a sun pull on a planet?

47. 13.10 Black Holes
The gravitational field strength near a giant star that collapses to become a black hole is the same before collapse (left) and after collapse (right).

48. Force and distance will be two of the variables we will be looking at today. Which one would be considered the independent variable and which would be the dependent variable?

49. 13.11 Universal Gravitation
Recent evidence suggests the universe is not only expanding, but accelerating outward.
It is pushed by an anti-gravity dark energy that makes up an estimated 73 percent of the universe.
Twenty-three percent of the universe is composed of the yet-to-be discovered particles of exotic dark matter.
The concepts of dark matter and dark energy will continue to inspire exciting research throughout this century.

50. 3/13
What is the relationship between gravitational force and distance? (is it reduced by, directly proportional to, independent of)
What would happen to your weight if the volume of the earth was smaller but the mass was the same?
Tomorrow
Gravity quiz
Notebook check

51. 13.4 Newton’s Law of Universal Gravitation
The Universal Gravitational Constant, G
What happens to F if
One mass is half as much
Both masses are twice as much.
The distance is tripled
Hint, substitute a one for every thing then do what the question is asking you to do.

52. 13.11 What is up with Uranus?
Until the middle of the last century astronomers were puzzled by unexplained perturbations (path changes) of the planet Uranus.
The source of Uranus’s perturbation was uncovered in 1845 and 1846 by two astronomers, John Adams in England and Urbain Leverrier in France.
Applying Newton’s law of gravitation, both astronomers concluded that there was a body beyond the orbit of Uranus.
The planet Neptune was discovered.

53. Are you ready for the quiz?
Notebook check, dates from

54. 13.10 Black Holes
The size of the sun is the result of a “tug of war” between two opposing processes: nuclear fusion and gravitational contraction.

55. Blackholes Gravity always wins! Future questions
Do black holes have mass?

56. Finish gravity post test
Finish gravity post test. Use evidence from your computer simulation to support your reasoning in the last question. What comes to mind when you think of universal gravitation?
Keep variable a one and everything a

57. Could you survive a plane crash. Why or why not
Could you survive a plane crash? Why or why not? How could you test this?
If you dropped a penny from a tall building could it kill a person?

58. What did you think of the final?
How do you think you did on the forbidden kingdom final?
Discuss number five
Introduce astronomy presentations part two: gravity

59. What are some characteristics of a strong presentation?
Which topic did you decide?
Today
Study your topic and generate two questions

60. What comes to mind when you think of gravity?

61. 13.2 The Falling Moon
This original drawing by Isaac Newton shows how a projectile fired fast enough would fall around Earth and become an Earth satellite.

62. What is the main idea behind your presentation?
What is a future question you can ask based on your presentation?
If you weight 160 pounds on the Earth’s surface what would be your weight if you climbed a ladder that was as long as the earths radius?

63. 13.2 The Falling Moon
The moon was already known to be 60 times farther from the center of Earth than an apple at Earth’s surface.
The apple will fall 5 m in its first second of fall.
Newton reasoned that gravitational attraction to Earth must be “diluted” by distance.
The influence of gravity should be diluted to 1/60 of 1/60.
In one second the moon should fall 1/(60)2 of 5 m, which is 1.4 millimeters.

64. 13.4 Newton’s Law of Universal Gravitation
Newton’s law of universal gravitation states that every object attracts every other object with a force that for any two objects is directly proportional to the mass of each object.
Newton deduced that the force decreases as the square of the distance between the centers of mass of the objects increases.
The magnitude of G is given by the magnitude of the force between two masses of 1 kilogram each, 1 meter apart: newton. (In scientific notation: G = 6.67 × 10−11 N·m2/kg2)

66. T2/ a3 period squared = axis cubed
Planet Semimajor axis (1010m) PeriodT (y) T2/a3(10-34y2/m3)
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
Kepler’s third law
T2/ a3 period squared = axis cubed

67. 3/14 Are you ready for the quiz?
What are two ways of reducing your weight without exercise or dieting?
Notebook check # of days since 3/3
Hints
Weight is the same thing as force

68. What topic did you choose?
What are some strong communication skills?
What are some strong listening skills

69. 13.4 Newton’s Law of Universal Gravitation
The force of gravity between objects depends on the distance between their centers of mass.

70. 12/1/10
Think of two questions that your presentation will answer.

71. 12/2 warm up Is your presentation ready?
What is one part that could use work?
Take about 10 minutes to practice your explanations with your group members