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
   • Heat from the ocean floor
   • Rivers flowing into the sea
   • Wind blowing over the water
2. 2.

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

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

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

   • Straight up
   • To the left
   • To the right
   • It does not turn them
5. 4.

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

   Use the picture in question 3.

   • To the right
   • No deflection
   • To the left
   • Straight toward the equator
6. 5.

   What causes the Coriolis effect, by Milo's reading (NOAA)?

   Use the picture in question 3.

   • The Moon's pull
   • Earth's rotation on its axis
   • Salt in the water
   • Wind blowing on the water
7. 6.

   Five gyres on a world map with their turning directions. Why are there no gyres at the equator, by Pia's reading (NOAA)?

   • The winds are too strong there
   • The water is too warm to turn
   • Gyres there turn both ways at once
   • The Coriolis effect is not present there
8. 7.

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

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

9. Read this first

   Use this

   Wind pushing surface water offshore as cold water rises.

10. 8.

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

    • Deep, cold water rising toward the surface
    • Waves breaking on the shore
    • Rain filling up the ocean
    • Warm surface water sinking toward the deep ocean
11. 9.

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

    • The rising water is rich in nutrients
    • The rising water is warm and nutrient-poor
    • Upwelling pushes the fish to shore
    • Upwelled water is fresh
12. 10.

    What starts coastal upwelling, by Esme's reading (NOAA)?

    • Surface water piling up and sinking
    • Sea ice melting
    • Rivers adding fresh water
    • Wind pushing surface water away, so deeper water rises