Currents and Climate

1. Currents and Climate Science 9.2

2. Standards • Science 6.4 a Students know the sun is the major source of energy for Earth’s surface. • Science 6.4 e Students know differences in pressure, heat, air movement and humidity results in a change in weather.

3. Language of the Discipline • El Nino • La Nina • Salinity • Upwelling

4. Anticipatory Set • Once upon a time, a family was strolling along a beach in Washington and noticed sneakers covered the beach. They had been washed up to shore. A few weeks later the same sneakers showed up in Oregon. After that they showed up in Hawaii! How is this possible?

5. Input/ Surface Currents • Affect water to a depth of several hundreds meters are driven mainly by winds. • Currents are a large stream of moving water that flows through the ocean. • Suns radiation is the ultimate source of energy that powers global winds and surface currents in the ocean. • Continentals blocks and redirect the flow of currents.

6. Coriolis Effects • Causes global winds to curve as a results of Earth’s rotation • It causes surface currents to curve to the right in the Northern hemisphere and to curve to the left in the Southern hemisphere

8. Effects on Climate • Surface current warms or cools the air above it, influencing the climate of the land near the coast. • Winds pick up moisture as they blow across warm water currents. • Cold water currents cool the air above them. Cold air holds less moisture and brings cool, dry weather to the land.

9. El Nino and La Nina • El Nino and La Nina are short term changes in the tropical Pacific Ocean caused by changes in ocean surface currents and prevailing winds. • Warm water event: El Nino begins with unusally wind patters. It causes the ocean to become warm. • Occurs every 2 to 7 years. Brings heavy rains, flooding, and mudslides to California

10. El Nino and La Nina • La Nina when surface waters are colder than normal. Brings colder than normal winters and greater precipitation to the Pacific. • La Nina causes greater hurricane activity.

12. Guided Practice Independent Practice • Guided Practice • Science workbook pg. 180. Complete outline and #1-3 • STOP! Raise your hand for a stamp. • “R” got to back table • Independent Practice • Science workbook pg. 181 #4-8

13. Deep Currents • Deep currents are caused by differences in the density of ocean water. • Depends on temperature and salinity • The sinking of dense, cold water with high salinity occurs in deep currents formed in the oceans near the poles.

14. Global Conveyer Belt • Deep currents move and mix water around the world. They carry cold water from the poles toward the equator. • Deep currents flow slowly. • Moves water from the tropics towards the poles and cold water to the equator. • Dense water sinks near the poles it spreads out and mixes with surrounding water.

15. Upwelling • Upwelling brings up tiny ocean organisms, minerals, and other nutrients from the deeper layers of the water. • Occurs in the Pacific Ocean. • The movement of cold, deep ocean water to replace warm water at the surface. • March- September • El Nino prevents upwelling from occurring

17. Modeling • Identify 5 key components that are important to Currents and climates. • 1. Surface currents are driven mainly by winds • 2. Surface currents warms or cools the air around it • 3. California Current and Davidson Current are two important currents. • 4. Continents block and redirect the flow of currents • 5. Coriolis changes global winds

18. Checking for Understanding • Identify 5 key components that are important to El Nino and La Nina

19. Guided PracticeIndependent Practice • Guided Practice – Worksheet #1-5 • Stop! Raise your hand and have your answers checked. • Independent Practice – Worksheet # 6-10