El Niño and La Niña

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

2. 1.

   What is El Niño, by Ari's reading (NOAA)?

   • Cooler-than-normal surface water in the eastern tropical Pacific Ocean
   • Stronger upwelling of cold water off South America
   • A winter storm that comes each year
   • Warmer-than-normal surface water in the eastern tropical Pacific
3. 2.

   What is La Niña, by Bo's reading (NOAA)?

   Use the picture in question 1.

   • Warmer-than-normal surface water in the eastern tropical Pacific Ocean
   • A drop in sea level worldwide
   • A permanent current
   • Cooler-than-normal surface water in the eastern tropical Pacific
4. 3.

   A number line of anomalies above and below zero. NOAA: about how large are these sea-surface temperature changes, by Kira's reading?

   • About 0.003 °C
   • Up to about 3 °C (6 °F), and usually less
   • About 10 to 15 °C in each event across the Pacific
   • About 30 °C

5. Read this first

   Use this

   Trade-wind arrows of different lengths across the Pacific.

6. 4.

   Normally, which way do the tropical Pacific trade winds blow, by Jun's reading (NOAA)?

   • From north to south
   • They do not blow
   • From east to west, toward Asia
   • From west to east, toward South America
7. 5.

   What happens to the trade winds during El Niño, by Luz's reading (NOAA)?

   • They stay the same
   • They turn north
   • They grow stronger
   • They weaken, and can even reverse

8. Use this

   A timeline with irregularly spaced warm and cool episodes.

9. 6.

   How often do El Niño and La Niña events occur, by Noah's reading (NOAA)?

   • Every 2 to 7 years on average, not on a set schedule
   • Once a century
   • Every month
   • Every year, like the seasons
10. 7.

    How long does an El Niño or La Niña episode typically last, by Pia's reading (NOAA)?

    • One day
    • About 50 years
    • About 9 to 12 months
    • About one week
11. 8.

    Which happens more often, by Ren's reading (NOAA)?

    • La Niña
    • Neither has ever occurred
    • El Niño
    • They alternate exactly, year by year

12. Use this

    Map of the U.S. with the jet stream dipping south or north.

13. 9.

    During an El Niño winter, what usually happens in the southern United States, by Tala's reading (NOAA)?

    • No change
    • Wetter conditions than usual
    • Much colder, drier air
    • Drier conditions than usual
14. 10.

    During La Niña winters, what usually happens in the southern United States, by Zee's reading (NOAA)?

    • Drier and warmer than normal
    • No change
    • Steady snow
    • Wetter and cooler than normal