Surface ocean currents and the Coriolis effect

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   World map with current arrows. What mainly drives surface ocean currents, by Ari's reading (NOAA)?

   • Differences in salt, by themselves
   • Rivers flowing into the sea
   • Wind blowing over the water
   • Heat from the ocean floor
3. 2.

   About how deep do wind-driven currents reach, by Bo's reading (NOAA)?

   • About 10,000 m
   • Just the top 1 cm
   • The upper 100 m or so
   • Down to the sea floor
4. 3.

   What drives deep-ocean currents instead, by Kira's reading (NOAA)?

   Use the picture in question 2.

   • The Moon's light
   • Differences in density from temperature and salinity
   • Surface wind, by itself
   • The engines of ships
6. 4.

   In the Northern Hemisphere, which way does the Coriolis effect turn moving air and water, by Jun's reading (NOAA)?

   • It does not turn them
   • Straight up
   • To the right
   • To the left
7. 5.

   In the Southern Hemisphere, which way are moving air and water deflected, by Luz's reading (NOAA)?

   Use the picture in question 4.

   • To the left
   • No deflection
   • To the right
   • Straight toward the equator

8. Read this first

   Use this

   Five gyres on a world map with their turning directions.

9. 6.

   Which way do Northern Hemisphere gyres turn, by Noah's reading (NOAA)?

   • They switch with each season
   • They do not turn
   • Counterclockwise
   • Clockwise
10. 7.

    Why are there no gyres at the equator, by Pia's reading (NOAA)?

    • The Coriolis effect is not present there
    • The winds are too strong there
    • Gyres there turn both ways at once
    • The water is too warm to turn
11. 8.

    What is a western boundary current like, by Ren's reading (NOAA)?

    • Strong and narrow
    • Deep and cold, driven by salt
    • Tidal, turning twice a day
    • Weak and broad

12. Use this

    Wind pushing surface water offshore as cold water rises.

13. 9.

    What is upwelling, by Tala's reading (NOAA)?

    • Waves breaking on the shore
    • Warm surface water sinking toward the deep ocean
    • Rain filling up the ocean
    • Deep, cold water rising toward the surface
14. 10.

    Why are fishing grounds often good where upwelling occurs, by Zee's reading (NOAA)?

    • Upwelling pushes the fish to shore
    • Upwelled water is fresh
    • The rising water is warm and nutrient-poor
    • The rising water is rich in nutrients