Worksheet

Deep ocean currents: cold, salty water sinks

Grade 9 Science Worksheet - Building Confidence

NameDate

Circle the best answer.

  1. The global conveyor drawn on a world map. What does the word thermohaline refer to, by Ari's reading (NOAA)?

    • Depth and pressure
    • Temperature and salinity
    • Tides and the pull of the Moon
    • Wind and waves

  2. Read this first

    Use this

    Wind arrows above, density arrows far below.

  3. What drives deep-ocean currents, by Bo's reading (NOAA)?

    • Rivers
    • Differences in density from temperature and salinity
    • Tides
    • Strong surface winds blowing steadily across the open ocean

  4. NOAA: winds drive currents in the upper 100 m. Where do the density-driven currents flow, by Kira's reading?

    • Thousands of meters below the surface
    • Inside rivers
    • Just in the top 100 m
    • Near the surface, pushed along by the wind

  5. Use this

    Sea ice forming above saltier, sinking water.

  6. When sea ice forms, what happens to the salt, by Luz's reading (NOAA)?

    • It turns into fresh water
    • It rises into the air
    • It freezes into the ice
    • It is left behind, making nearby water saltier

  7. Why does water near forming sea ice sink, by Milo's reading (NOAA)?

    • It warms up and expands
    • It gets colder and saltier, so its density rises
    • It gets fresher and lighter
    • The wind pushes it down

  8. Use this

    The global conveyor drawn on a world map.

  9. Where does the global conveyor belt start, by Noah's reading (NOAA)?

    • In the middle of the Indian Ocean
    • Near the pole in the North Atlantic
    • At the equator in the Pacific
    • At the mouth of a river

  10. Where is the conveyor recharged with more cold, dense water, by Pia's reading (NOAA)?

    • In the warm Indian Ocean
    • Off a tropical island
    • Around Antarctica
    • At the equator

  12. About how long does a cubic meter of water take to complete the conveyor, by Ren's reading (NOAA)?

    • About 1,000 years
    • About 1 million years
    • About 10 days
    • About 1 year

  13. NOAA: the conveyor moves a few cm a second; wind and tidal currents move tens to hundreds. Which is slower, by Tala's reading?

    Use the picture in question 8.

    • They move at the same speed
    • Tidal currents
    • Wind-driven currents
    • The conveyor

  14. The global conveyor drawn on a world map. NOAA: the conveyor moves more than 100 times the flow of the Amazon River. If the river's flow is 1 unit, how much does the conveyor move, by Esme's math?

    • More than 100 units
    • Less than 1 unit
    • About 1 unit
    • About 10 units
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Deep ocean currents: cold, salty water sinks

Answer Key - Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

  1. The global conveyor drawn on a world map. What does the word thermohaline refer to, by Ari's reading (NOAA)?

    • Depth and pressure
    • Temperature and salinity
    • Tides and the pull of the Moon
    • Wind and waves

  2. Read this first

    Use this

    Wind arrows above, density arrows far below.

  3. What drives deep-ocean currents, by Bo's reading (NOAA)?

    • Rivers
    • Differences in density from temperature and salinity
    • Tides
    • Strong surface winds blowing steadily across the open ocean

  4. NOAA: winds drive currents in the upper 100 m. Where do the density-driven currents flow, by Kira's reading?

    • Thousands of meters below the surface
    • Inside rivers
    • Just in the top 100 m
    • Near the surface, pushed along by the wind

  5. Use this

    Sea ice forming above saltier, sinking water.

  6. When sea ice forms, what happens to the salt, by Luz's reading (NOAA)?

    • It turns into fresh water
    • It rises into the air
    • It freezes into the ice
    • It is left behind, making nearby water saltier

  7. Why does water near forming sea ice sink, by Milo's reading (NOAA)?

    • It warms up and expands
    • It gets colder and saltier, so its density rises
    • It gets fresher and lighter
    • The wind pushes it down

  8. Use this

    The global conveyor drawn on a world map.

  9. Where does the global conveyor belt start, by Noah's reading (NOAA)?

    • In the middle of the Indian Ocean
    • Near the pole in the North Atlantic
    • At the equator in the Pacific
    • At the mouth of a river

  10. Where is the conveyor recharged with more cold, dense water, by Pia's reading (NOAA)?

    • In the warm Indian Ocean
    • Off a tropical island
    • Around Antarctica
    • At the equator

  12. About how long does a cubic meter of water take to complete the conveyor, by Ren's reading (NOAA)?

    • About 1,000 years
    • About 1 million years
    • About 10 days
    • About 1 year

  13. NOAA: the conveyor moves a few cm a second; wind and tidal currents move tens to hundreds. Which is slower, by Tala's reading?

    Use the picture in question 8.

    • They move at the same speed
    • Tidal currents
    • Wind-driven currents
    • The conveyor

  14. The global conveyor drawn on a world map. NOAA: the conveyor moves more than 100 times the flow of the Amazon River. If the river's flow is 1 unit, how much does the conveyor move, by Esme's math?

    • More than 100 units
    • Less than 1 unit
    • About 1 unit
    • About 10 units