Oceanography 10. Tides Study Guide (7A)

Transcription

1 Tides Study Guide (Topic 7A) page 1 Oceanography 10 Name: Tides Study Guide (7A) Note: Do not forget to include the units of your answers. 1. Use the tide chart below to determine the height and time of the high tides and low tides 1 st High Tide 1 st Low Tide 2 nd High Tide 2 nd Low Tide Time Height Generated using the WWW Tide/Current Predictor: 2. What is the largest tidal range for the day? 3. What is the smallest tidal range for the day?

2 Tides Study Guide (Topic 7A) page 2 4. How long does it take the Moon to orbit the Earth one time? How long does it take the Earth to rotate one time on its axis? (In other words, how long does it take the Earth to spin all the way around one time?) How long does it take the Earth to orbit the Sun one time? 5. Is the gravitational attraction stronger between Large, Heavy Objects / 2 large, heavy objects or 2 small, light objects? Small, Light Objects Is the gravitational attraction stronger between Close Together / Far Apart 2 objects that are close together or far apart? 6. Which bulge in the ocean s surface is larger, the bulge facing Towards Moon / towards the Moon or the bulge facing away from the Moon? Away from Moon / Both Are the Same 7. Why does the Earth orbit the Earth-Moon barycenter? 8. The Bulges of the Ocean a. Sketch the bulges in the ocean for the arrangement of the barycenter, Earth, Moon, and Sun shown below. ( B is the barycenter, E is the Earth, M is the Moon, and S is the Sun.) b. Label the bulge(s). In other words, write the word bulge on or next to the bulge(s). c. Label the locations of high tide and low tide. B E You may use arrows to indicate the specific location of a bulge, a high tide, or a low tide. M S

3 Tides Study Guide (Topic 7A) page 3 9. Sketching Bulges: Relationships between the Bulges, High and Low Tides, and the Moon In each of the pictures below, sketch the bulges in the ocean for the arrangement of the barycenter, Earth, Moon, and Sun shown below. ( B is the barycenter, E is the Earth, M is the Moon, and S is the Sun.) Label the bulge(s). In other words, write the word bulge on or next to the bulge(s). Label the locations of high tide and low tide. Write HT for high tide and LT for low tide. You may use arrows to indicate the specific location of a

4 Tides Study Guide (Topic 7A) page The Moon orbits the Earth twice each day. We experience a high tide when the Moon is overhead and pulls a bulge in the ocean to our coast. What is wrong with this statement? 11. About how long does it take the ocean to change from high tide to low tide? Why does it take this period of time for the ocean to change from high tide to low tide? Explain using the bulge theory of the tides. It takes for the Earth to spin once all the way around. When a location goes into a bulge, the location experiences tide. When a location goes out of a bulge, the location experiences tide. Since there are bulges in the ocean, each location on Earth goes into a bulge (high tide) and out of a bulge (low tide) twice each day. Since bulges are on opposite sides of the Earth, a location goes from inside a bulge (high tide) to outside bulge (low tide) in turn of the Earth which takes hours. 12. The Earth goes in and out of the bulges in the ocean twice each day. What is wrong with this statement? How can it be corrected or fixed? 13. Do tides get earlier or later each day? By how much? Earlier / Later by Circle the answer below which best explains why tides get earlier or later each day according to the bulge theory of tides. The Barycenter / Moon / Sun travels around the Earth each day. The Barycenter / Moon / Sun orbits the Earth more slowly than the Earth rotates. The Earth s Rotation / Moon s Orbit / Sun s Orbit is slowing down (slowly). The bulges drag against the ocean bottom, slowing them down. The bulges run into the continents, slowing them down. 14. True or False? Every location on the Earth experiences high tide as the same time. In other words, if it is high tide in New York, it is also high tide in Los Angeles. Discuss the bulges in the ocean, and use them to explain your choice.

5 Tides Study Guide (Topic 7A) page 5 NOTE: When I ask what if? questions, I will only change ONE thing, and that is the only thing that you should consider when considering your answer. For example, if the size of the Moon changes, all other factors remain the same: the Moon s distance from the Earth, the speed of the Moon s orbit, the speed of the Earth s rotation, and so on do not change. 15. Suppose that the Moon was twice as large. How would the height of the tides be different? The (A) pull of the (B) would be (C), so the high tides would (D) they are now because (F) water would be pulled (G) the places where it is high tide (the bulges), and the low tides would (E) they are now because (F) water would be pulled (G) the place(s) where it is low tide (outside the bulges). 16. Suppose that the Moon was two times farther from the Earth. How would the height of the tides be different? The (A) pull of the (B) would be (C), so the high tides would (D) they are now because (F) water would be pulled (G) the places where it is high tide (the bulges), and the low tides would (E) they are now because (F) water would be pulled (G) the place(s) where it is low tide (outside the bulges). Possible Answers A: give the name of the force that pulls on the water in the ocean B: Barycenter, Coriolis effect, Earth, Moon, Sun C: stronger, weaker, about the same D: be higher than, not be as high as, be about the same as E: be lower than, not be as low as, be about the same as F: more, less, about the same amount of G: towards, away from

6 17. Tides Study Guide (Topic 7A) page 6

7 Tides Study Guide (Topic 7A) page Spring and Neap Tide Conditions Are high tides extremely high or not very high during these conditions? Are low tides extremely low or not very low during these conditions Which phases of the Moon are these conditions associated with? How long does it take the ocean to switch from spring tide conditions to neap tide conditions? Spring Tide Conditions Neap Tide Conditions 19. Which has a stronger influence on the tides, the Moon or the Sun? Moon / Sun / Both About the Same 20. How many bulges does the Moon cause in the ocean? 21. Consider both the effects of the Moon and the Sun. How many bulges are there in the ocean? 22. What is the phase of the moon in each of the pictures below? Is the Earth experiencing spring tide conditions or neap tide conditions? Spring Tides Full Moon Spring Tides New Moon E S E S #1 #3 Neap Tides Half Moon Neap Tides Half Moon E S E S #2 #4

8 23. Label the phase of the Moon and the tide conditions (spring tides or neap tides) for the 4 positions of the Moon relative to the Earth and the Sun in the picture below. Tides Study Guide (Topic 7A) page During spring tide conditions, the high tides are (A) and the low tides are (B) because the (C) gravitational pull on the water pulls (D) water from the places where it is low tide to the places where it is high tide (the bulges). A: higher, not as high, about the same C: stronger, weaker, about the same B: lower, not as low, about the same D: more, less, about the same amount of Why is the gravitational pull different during spring tide conditions? 25. During neap tide conditions, the high tides are (A) and the low tides are (B) because the (C) gravitational pull on the water pulls (D) water from the places where it is low tide to the places where it is high tide (the bulges). Why is the gravitational pull different during neap tide conditions?

9 26. True or False? Every location on the Earth experiences spring tide conditions at the same time. In other words, if New York is experiencing spring tide conditions, Los Angeles also is experiencing spring tide conditions. Discuss the bulges in the ocean, and use them to explain your choice. Tides Study Guide (Topic 7A) page What if? Complete the following sentences. (1) The height of high and low tides is determined by:. (2) How often the tides switch from high tide to low tide is determined by:. (3) How often the tides switch from spring tide conditions to neap tide conditions is determined by:. Possible Answers: how fast the Earth rotates (spins) how fast the Earth orbits the Sun (goes around the Sun) how fast the Moon orbits the Earth (goes around the Earth) the strength of the gravitational pull of the Moon and Sun

10 28. Suppose that the Moon was twice as large. How would the tides be different? (Class) Tides Study Guide (Topic 7A) page 10 High tides would: be higher not be as high be about the same (no change) Low tides would: be lower not be as low be about the same (no change) 29. Suppose that the Moon was two times farther from the Earth. How would the tides be different? (Class) High tides would: be higher not be as high be about the same (no change) Low tides would: be lower not be as low be about the same (no change) 30. Suppose that the Earth rotated twice as fast. (Class) (In other words, the Earth s spins all the way around on its axis faster. Only the speed of rotation changes. There are no other changes: mass, distance, etc.) Would the timing of the tides be different? If so, how? High tide & low tide would happen more often (less time between high tides and low tides) High tide & low tide would happen less often (more time between high tides and low tides) No change or very little change (less than an hour) Would the timing of spring and neap tide conditions over a cycle of the moon be different? If so, how? Spring & neap tide conditions would happen more often (less time between spring & neap tide conditions) Spring & neap tide conditions would happen less often (more time between spring & neap tide conditions) No change Would the height of the high tides and low tides be different during spring tide conditions? If so, how? High Tides: Higher Not as high No change Low Tides: Lower Not as low No change 31. Suppose that the Moon orbited the Earth more quickly, so that it took half as long to go around one time. (Only the orbital time changes. There are no other changes: mass, distance, etc.) (Class) Would the timing of the tides be different? If so, how? High tide & low tide would happen more often (less time between high tides and low tides) High tide & low tide would happen less often (more time between high tides and low tides) No change or very little change (less than an hour) Would the timing of spring and neap tide conditions over a cycle of the moon be different? If so, how? Spring & neap tide conditions would happen more often (less time between spring & neap tide conditions) Spring & neap tide conditions would happen less often (more time between spring & neap tide conditions) No change Would the height of the high tides and low tides be different during spring tide conditions? If so, how? High Tides: Higher Not as high No change Low Tides: Lower Not as low No change

11 32. What if? Challenge Questions Consider each situation below. How would the tides be different? A. Suppose that the Moon was twice as large. B. Suppose that the Moon was half as large. C. Suppose that the Moon was two times closer to the Earth. D. Suppose that the Moon was two times farther from the Earth. Tides Study Guide (Topic 7A) page 11 E. Suppose that the Earth rotated twice as fast. In other words, suppose that the Earth made one complete revolution in 12 hours. F. Suppose that the Earth rotated half as fast. In other words, suppose that the Earth made one complete revolution in 48 hours. G. Suppose that the Moon orbited the Earth twice as fast. In other words, suppose that the Moon completed one trip around the Earth in about 14 days. H. Suppose that the Moon orbited the Earth half as fast. In other words, suppose that the Moon completed one trip around the Earth in about 56 days. I. Suppose that the Earth orbited the Sun twice as fast. In other words, suppose that the Earth completed one trip around the Sun in about 6 months. J. Suppose that the Earth orbited the Sun half as fast. In other words, suppose that the Earth completed one trip around the Sun in about 6 months. Possible Answers: HT/H - High tides would be higher than they are now. HT/Not H - High tides would not be as high as they are now. LT/L - Low tides would be lower than they are now. LT/Not L - Low tides would not be as low as they are now. T/Faster - The tide would change from high tide to low tide and back again much more often. T/Slower - The tide would change from high tide to low tide and back again much less often. ST/NT/Faster - The tides would change from spring tide conditions to neap tides conditions and back again much more often. ST/NT/Slower - The tides would change from spring tide conditions to neap tides conditions and back again much less often. None - There would be little or no change in the tides.

12 Tides Study Guide (Topic 7A) page True or false? There are places where the normal tidal cycle is 1 high tide and 1 low tide each day. 34. Why can t the tidal bulges stay underneath ( keep up with ) the Moon? Give at least 1 reason. The Barycenter s / Sun s pull gets in the way. The Barycenter / Moon / Sun orbits the Earth more slowly than the Earth rotates. The bulges drag against the bottom of the ocean. The continents get in the way. 35. The bulge theory of tides does not accurately describe the motion of the tidal bulges over the surface of the Earth: they do not travel around the Earth each day. Describe how the tidal bulges really move in the ocean basins. From North to South / East to West and then back again. Giant Circles The bulges do not move over the Earth s surface; they stay in the same spot on the Earth. 36. How are tides different during storms? High Tides: Higher Not as high No change Low Tides: Lower Not as low No change 37. When is the best time for a ship to try to enter a harbor? Close to High / Low tide when the tide is Rising / Sinking in the ocean. 38. When is the best time for a ship to try to leave a harbor? Close to High / Low tide when the tide is Rising / Sinking in the ocean. 39. Do high tides in a bay (estuary) occur earlier or later Earlier / Later / At the Same Time than the high tides along the coast? 40. Do low tides in a bay (estuary) occur earlier or later Earlier / Later / At the Same Time than the low tides along the coast? (1 pt)

13 Tides Study Guide (Topic 7A) page What are the best tide conditions for tide pooling? (Class) High / Low tide during Spring / Neap tide conditions 42. How is the salinity of the water in tide pools different from the water in the ocean? often saltier than the ocean often fresher than the ocean sometimes much saltier than the ocean, sometimes much fresher than the ocean (the salinity of the water in the tide pools is more variable, more extreme) usually not as fresh or salty as the ocean (the salinity of the water in the tide pools is more stable, more constant) 43. How is the temperature of the water in tide pools different from the water in the ocean? often warmer than the ocean often cooler than the ocean usually warmer than the ocean or cooler than the ocean (the temperature of the water in the tide pools is more variable, more extreme) usually not as warm or cold as the ocean (the temperature of the water in the tide pools is more stable, more constant) 44. Which of the following strikes tide-pool animals and algae with the greatest force (physical impact) each day? (Mark all that apply.) California Current High Tides Longshore Transport Winds Earthquakes Low Tides Waves 45. True or false? Tide-pool animals are often smashed by rolling or flying sediments. 46. Mark examples of the harsh physical conditions that organisms must endure in the intertidal zone. (Mark all that apply.) In addition to the Tides (7A) reading, you can refer to the Rocky Shore ASA (14B) for more information about these topics. covered by too much water: pressure is too high and crushes them crushed by the California Current / Flying & Rolling Sediments / Rip Currents / Waves / Tides too hot during the day during High / Low tide too cold at night during High / Low tide water in tide pools is too fresh due to Evaporation / Rain water in tide pools is too salty due to Evaporation / Rain 47. What adaptation do many animals who live on a rocky shoreline have that allows them to survive the harsh physical conditions at high tide and low tide? 48. Most of the animals that are found in tide pools when you go tide pooling: are benthos carried in a high tide and left on the shore are zooplankton carried in a high tide and left on the shore drift at high tide and settle in new places each day at low tide live in the tide pools at both high tide and low tide