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)?

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

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

   • Surface wind, by itself
   • Differences in density from temperature and salinity
   • The Moon's light
   • The engines of ships
4. 3.

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

   • To the right
   • To the left
   • It does not turn them
   • Straight up
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
   • Straight toward the equator
   • To the left
   • No deflection
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 Coriolis effect is not present there
   • The winds are too strong there
   • The water is too warm to turn
   • Gyres there turn both ways at once
8. 7.

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

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

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
    • Warm surface water sinking toward the deep ocean
    • Rain filling up the ocean
11. 9.

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

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

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

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