Tides & Currents: Motion in the Ocean — Quiz

Multiple Choice Questions

1. According to the resource, approximately what percentage of cargo shipped to and from the United States is transported by water?
A) 50%
B) 75%
C) 98%
D) 100%

2. What is the primary purpose of NOAA's Center for Operational Oceanographic Products and Services (CO-OPS)?
A) To launch weather satellites
B) To collect and distribute oceanographic observations and predictions for safe maritime transportation
C) To regulate international shipping laws
D) To study marine wildlife populations

3. What does the PORTS® network provide to mariners in major U.S. harbors?
A) Historical shipwreck data
B) Fishing regulations
C) Real-time water levels, currents, air gap, and weather data
D) Ship repair services

4. According to the resource, what three factors determine the height of surface ocean waves?
A) Water temperature, salinity, and depth
B) Wind speed, duration of wind, and fetch length
C) Tide level, moon phase, and current speed
D) Latitude, longitude, and season

5. What is a "Sverdrup-Munk-Bretschneider nomogram" used for?
A) Calculating tide times
B) Predicting wave height from wind conditions
C) Measuring the Coriolis effect
D) Mapping ocean currents

6. According to the worksheet answer key, what is the magnitude of the Coriolis acceleration at the equator?
A) It is at its maximum
B) It is zero
C) It doubles
D) It cannot be calculated

7. Which piece of information is needed to estimate current speed using drifter study data?
A) Only the water temperature
B) Only the wind speed
C) The distance between two points and the total time elapsed
D) The depth of the ocean floor

Short Answer Questions

8. Based on the Coriolis acceleration calculations in the worksheet (e.g., the small value calculated for Tijuana), explain why the Coriolis effect is negligible for small objects like soccer balls or walking humans, but becomes significant for ocean currents.

9. Using the worksheet's method, explain what two pieces of measured data (from a drifter study) are needed to calculate both the speed and direction of an ocean current.

10. List two learning objectives from the lesson that describe what students should be able to do regarding ocean currents and the Coriolis Effect.

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Answer Key

1. C — 98%
2. B — To collect and distribute oceanographic observations and predictions for safe maritime transportation
3. C — Real-time water levels, currents, air gap, and weather data
4. B — Wind speed, duration of wind, and fetch length
5. B — Predicting wave height from wind conditions
6. B — It is zero
7. C — The distance between two points and the total time elapsed

8. The Coriolis acceleration formula involves velocity and latitude, producing only a very small acceleration value (e.g., 0.081 cm/sec² for a 10 m/s object at Tijuana's latitude). This is negligible for small, fast-moving objects over short distances/times. However, when this small acceleration acts on very large masses of water over very long distances (like ocean currents), the cumulative effect becomes significant.

9. To calculate current speed, you need the distance between two points (where the drifter started and ended) and the total time elapsed. Speed is calculated by dividing distance by time. The direction is estimated from the path/bearing between the starting and ending points.

10. Any two of the following:

• Students will identify the primary causes for ocean currents and waves.
• Students will explain how and why ocean currents vary at different latitudes.
• Students will explain the cause of the Coriolis Effect, and how this effect influences ocean currents.
• Students will calculate the magnitude of ocean currents, given data from drifter studies.