GRAVITY & ORBITS

1. GRAVITY & ORBITS

3. Mass vs. Weight • MASS: • Measure of the amount of matter in an object • Measured in grams & kilograms, by using a balance • Does not change with location • Cannot be zero

4. Mass vs. Weight • WEIGHT: • Measure of the pull of gravity on an object • Measured in ounces, pounds, and Newtons, by using a scale • Changes with location, depending on gravity • Can be zero

5. GRAVITY • A universal force • Every object with mass exerts an attractive force on other objects • Gravity depends on MASS and DISTANCE

6. Gravity, MASS & DISTANCE: • MASS: • The more mass an object has, the stronger its gravity will be • Less mass, weaker gravity • DISTANCE: • The closer together objects are, the stronger the gravitational pull • Farther apart, less gravitational pull

7. ORBITS (Solar System) An orbit is a balance of the gravity between the objects and the inertia of the smaller object. Gravity pulls the objects together inertia gravity Inertia causes the smaller object to continue traveling in a straight line Balanced orbit

8. FORMATION OF STARS & PLANETS

9. Solar system formed about 4.7 billion years ago from a giant cloud of gas and debris. The planets were formed by condensing matter due to gravity.

10. More dense materials were held near the sun by gravity, while less dense materials were pushed away by high temperatures, pressure and solar wind from the sun. Terrestrial (Rock) Dense Jovian (Gas) Low Density

11. Terrestrial Planets: • 4 closest planets to the Sun • Low mass (small) • High density (mostly rock)

12. Jovian Planets: • 4 farthest planets from the Sun • High mass (large) • Low density (mostly gas)

13. Gravity caused the Earth and the other planets to become layered due to density differences in their materials. (more dense materials sank to the interior of the planet, less dense materials rose to the surface)

15. Nebula – Birth of Star • Stars are formed in a Nebula. • A Nebula is a very large cloud of gas and dust in space.

16. How stars form: • Gravity makes dense region of gas more compact • Dense gases heat to extreme temperatures • At 10,000,000º C, nuclear fusion begins and it ignites into a star • Nuclear fusion: the nucleus of atoms fuse together to make heavier elements • The star will continue to fuse elements until there are no elements left. • This is when a star “dies” or burns out

18. The MOON, Gravity, and Ocean Tides

19. What Are Tides? • Tides are the daily rise and fall of Earth’s waters on its coastlines. • Tide comes in, level of water on the beach rises • Tide goes out, level of water on the beach goes down.

20. High tides are when the water reaches its highestpoint.

21. Low tides are when the water reaches its lowestpoint.

22. What Causes Tides? The gravitational pull from the Moon, and the rotation of the Earth on its axis, cause the ocean water to bulge, producing the tides.

23. The Moon pulls on the water on the side nearest to it more strongly than it pulls on the centerof the Earth. • This pull creates a bulge of water on the side of Earthfacingthe the Moon.

24. “Bulge” of Earth Gravitational pull Earth Sun Moon

25. In places where there are tidal bulges, hightideis occurring along the coastlines. High Tide High Tide

26. In places between the tidal bulges, lowtideis occurring along the coastlines. Low Tide Low Tide

27. Sun’s Gravity and Tides • The Sun is so largethat its gravity also affects tides. • At times, the Sun and Moonpull together on Earth’s waters in the samedirection. • At other times they pull in different directions.

28. Changes in the positions of Earth, the Moon, and Sun affect the height of tides during a month.

29. Spring tides occur 2 times a month, during a full and new moon when the Earth, Sun, and Moon are lined up. • Spring tides are higherand lower than normal tides.

30. Spring Tide

31. Spring Tide Low Tide High Tide High Tide Low Tide Full Moon New Moon

32. Neap tides occur in between spring tides, at the first and third quarters of the Moon when the Sun and Moon pull at rightangles to each other. • Neap tides are notas high or low as normal tides.

33. Neap Tides

34. Third Quarter Moon Neap Tide High Tide Low Tide Low Tide High Tide First Quarter Moon

36. Tides at a Monthly Glance

37. Study Jams Video

38. You arrive at the beach at 9:00 A.M. You lay a towel on the sand, and then you run 30 steps to reach the water’s edge. By 3:00 P.M., the water has almost reached your towel. What do you think happened? The tide came in.

39. The diagram below shows the possible positions of the moon relative to the Earth and sun during different tidal ranges. Use the diagram below to answer the questions that follow.

40. At which position would the moon be during a neap tide? A. 1 B. 2 C. 3 D. 4

41. At which position would the moon be during a spring tide? A. 1 B. 2 C. 3 D. 4

42. The tidal range would be greater when the moon is at position 3 than when the moon is at position 4 because… A. position 4 forms a 90° angle with the sun and the Earth. B. position 3 is very near a neap-tide position. C. position 3 is very near a spring-tide position. D. position 4 is very near a spring-tide position.