El Niño and La Niña

Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

1. 1.

   A timeline with irregularly spaced warm and cool episodes. A classmate says El Niño arrives every December like clockwork. Which reply fits NOAA, by Esme's reading?

   • Correct; it lasts all year, every year
   • No; it comes once a century
   • Correct; it comes each December
   • No; it often peaks near December but comes every 2 to 7 years, irregularly
2. 2.

   A student says La Niña is just a stronger El Niño. Which reply fits NOAA, by Jun's reading?

   • Correct; La Niña has weaker trades, just like a strong El Niño
   • No; La Niña is the cool phase, with stronger trade winds
   • No; La Niña has less upwelling
   • Correct; both are warm phases
3. 3.

   Map of the U.S. with the jet stream dipping south or north. A student says a change of 1 °C in the Pacific can't affect weather far away. Which reply fits NOAA, by Kira's reading?

   • Correct; small changes have no reach
   • No; small shifts move the rising air and shift the jet stream
   • Correct; the jet stream stays fixed no matter how the ocean warms
   • No; 1 °C flips the trade winds each day
4. 4.

   A number line of anomalies above and below zero. Model data: monthly Niño 3.4 anomalies are −0.6, −0.9 and −1.2 °C. What is the average, and which phase does it suggest, by Luz's math?

   • +0.9 °C, pointing to El Niño
   • −2.7 °C, pointing to La Niña
   • −0.9 °C, pointing to El Niño
   • −0.9 °C, pointing to La Niña
5. 5.

   A timeline with irregularly spaced warm and cool episodes. Episodes come every 2 to 7 years (NOAA). About how many could occur in 28 years, as a range, by Milo's math?

   • About 4 to 14
   • About 56 to 196
   • About 2 to 7
   • Exactly 28
6. 6.

   Cross-section of the Pacific warm layer. The normal 46 cm sea-level difference shrinks by half as the trades weaken (model data). What is the new difference, by Noah's math?

   • About 92 cm
   • About 44 cm
   • About 0 cm
   • About 23 cm
7. 7.

   Four evidence cards, labeled A to D. Which evidence best points to El Niño developing, by Pia's reading (NOAA)?

   • Stronger trades and cooler-than-normal water in the eastern Pacific
   • A cold week in Canada
   • More upwelling off South America
   • Weakening trades and warmer-than-normal eastern Pacific water
8. 8.

   Model map: rain shifts into the central Pacific and the western Pacific turns dry. Which phase fits, by Ren's reading (NOAA)?

   • A permanent shift
   • La Niña
   • El Niño
   • Normal conditions
9. 9.

   Map of the U.S. with the jet stream dipping south or north. Model data: a winter brings wet weather to the southern U.S. and mild, dry weather to the north. Which phase is most likely, by Tala's reading (NOAA)?

   • El Niño
   • Neutral, with no pattern
   • A permanent shift
   • La Niña
10. 10.

    Which summary of La Niña fits NOAA, by Ari's reading?

    • Trades weaken, and the eastern water warms
    • Upwelling stops completely
    • Southern U.S. winters turn wetter
    • Trades strengthen, upwelling grows, the east cools, the jet shifts north