UNIT 2: THE EARTH´S PHYSICAL CHARACTERISTICS. PART 2: THE EARTH´S HYDROSPHERE

1. UNIT 2: THE EARTH´S PHYSICAL CHARACTERISTICS. PART 2: THE EARTH´S HYDROSPHERE

2. In thisunityouwill… • - Understandthewatercycle • Learnaboutoceans and seas • Learnabout continental waters, such as glaciers, rivers, lakes and groundwater • Understandthewateris a vital resourceforusall 6minutes long video abouttheimportance of thewater in ourplnet

3. PAGES 30-31 THE WATER CYCLE THERE IS ALWAYS THE SAME AMOUNT OF WATER ON EARTH THIS CONTINUAL MOVEMENT OF WATER IS CALLED THE WATER CYCLE IT MOVES CONTINOUSLY BETWEEN THE ATMOSPHERE, THE OCEANS AND THE CONTINENTS IT SOMETIMES CHANGES STATE, AND CAN BE IN LIQUID, GAS OR SOLID FORM THIS CYCLE IS MADE UP OF THREE PHASES WATER CONDENSES IN THE AIR AND FORMS CLOUDS WHEN CLOUDS CANNOT ABSORB ANY MORE WATER, THERE IS PRECIPITATION IN THE FORM OF RAIN, SNOW OR HAIL WATER EVAPORATES, RISES AND COOLS IN THE ATMOSPHERE

4. 7:15 minuteeslong video aboutthewatercycle and thehydrosphere. Takethefirst 2:30 Thewatercyclesong (3:17)

5. True or False: Oceans and seas occupy the same Earth´s surface than the continents False They occupy 71% of the Earth´s surface and are mostly in the Southern Hemisphere

6. SALTWATER SALINITY IS HIGHER IN HOT, ENCLOSED SEAS BECAUSE THE PROPORTION OF SALT RISES WHEN THE WATER EVAPORATES ABOUT 97% OF THE EARTH´S WATER IS SALTWATER, LOCATED IN THE OCEANS AND SEAS SALINITY IS THE AMOUNT OF SALT DISSOLVED IN WATER THE SALIINITY OF THE DEAD SEA IS TEN TIMES HIGHER THAN ANY OTHER BODY OF SALTWATER. THIS MEANS THAT NOTHING CAN LIVE IN IT. WE CAN HOWEVER FLOAT IN IT VERY EASLY THE TEMPERATURE OF SALTWATER VARIES. IT IS WARMER NEAR THE SURFACE (12-30 ºC) AND COLDER IN DEEP WATER (4-1 ºc) SALTWATER IS DENSER THAN FRESH WATER. FOR THAT REASON NAVIGATION IS EASIER

7. FRESH WATER ABOUT THE 3% OF THE EARTH´S WATER IS FRESH WATER FOUND ON CONTINENTS AND ISLANDS MOST OF THIS WATER IS ICE AT THE POLAR REGIONS AND IN GLACIERS SOME OF IT IS GROUNDWAETER UNDER THE EARTH´S SURFACE ONLY A SMALL PROPORTION OF IT IS FOUND IN WATER VAPOUR AND IN LAKES OR RIVERS

9. SEAS AND OCEANS OF THE WORLD OCEANS ARE LARGE ACCUMULATIONS OF SALT WATER THAT FILL THE DEPRESSIONS OF THE EARTH´S CRUST AND SEPARATES THE CONTINENTS SEAS ARE PART OF THE OCEANS THAT ARE NEAR THE COASTS. THEY ARE NOT AS DEEP AS THE OCEANS

10. A 9:23 video longaboutwaves, tides and oceancurrents and alsothe machines usedtostudyoceans • OCEANIC WATERS THE WATER IN SEAS AND OCEANS IS IN CONSTANT MOVEMENT. THERE ARE THREE TYPES OF MOVEMENT WAVES TIDES OCEAN CURRENTS LARGE MASSES OF OCEAN WATER WHICH MOVE FROM ONE POINT OF AN OCEAN TO ANOTHER. THERE ARE TWO TYPES: WARM AND COLD CURRENTS (DEPENDING ON THE TEMPERATURE OF THE WATER SURROUNDING). ONDULATIONS ON THE SURFACE OF THE SEA CAUSED BY WINDS THE RISE AND FALL OF SEA LEVELS CAUSED BY THE INFLUENCE OF MOON. WHEN THE WATER LEVEL RISES, IT IS CALLED,HIGH TIDE. WHEN IT FALLS IT IS CALLED LOW TIDE.

11. WAVES WAVES ARE ONDULATIONS OF THE SURFACE OF THE WATER PRODUCED BY WIND. WAVES DO NOT MOVE FORWARD BUT GO UP AND DOWN IN A CIRCULAR MOTION. THEIR SHAPE CHANGES WHEN THEY COME INTO CONTACT WITH SEA FLOOR.

12. TIDES TIDES ARE THE DAILY RISE AND FALL OF THE WATER LEVEL. THEY ARE CAUSED BY GRAVITIONAL FORCES OF THE MOON AND THE SUN. WHEN THE WATER LEVEL RISES, IT IS CALLED HIGH TIDE. WHEN THE LEVEL FALLS, IT IS CALLED LOW TIDE. On the left, the top panel shows the force of gravity felt by the Earth from the Moon. In the right panel, the two images show how the Sun also contributes to the tides on Earth. The tidal force on the Earth from the Sun is WEAKER than the tidal force on the Earth from the Moon.

13. OCEAN CURRENTS OCEANS CURRENTS ARE LARGE MASSES OF WATER, SIMILAR TO RIVERS, WHIC CIRCULATE THROUG OCEANS . CURRENTS CAN BE COLD (IN BLUE) OR WARM (IN BLUE). WHEN THE TEMPERATURE OF A CURRENT IS HIGHER THAN THE WATER AROUND IT, IT IS A WARM CURRENT. WHEN THE TEMPERATURE OF A CURRENT IS COLDER THAN THE WATER AROUND IT , IT IS A COLD CURRENT. OCENS CURRENTS INFLUENCE THE CLIMATE OF THE COASTAL AREAS NEARBY.

14. CONTINENTAL WATER CONTINENTAL WATERS HAVE LOW SALINITY LEVELS. THEY ARE FRESHWATER AS OPPOSED TO SEAWATER. THEY CAN BE FOUND IN: AQUIFERS RIVERS GLACIERS LAKES LARGE ACCUMULATIONS OF WATER IN DEPRESSED AREAS OF THE EARTH´S CRUST THAT ARE MORE THAN ONE METER DEEP. CONTINUOUS COURSES OF WATER THAT FLOW NATURALLY ACCUMULATIONS OF SUBTERRANEAN WATER THAT ARE CAUSED BY WATER FILTRATIONS FROM THE SURFACE LARGE SLOW MOVING MASSES OF ICE THAT CAN BE FOUND IN POLAR REGIONS AND HIGH MOUNTAIN AREAS.

15. Science expert Emerald Robinson explains what a glacier is and how it forms (2´) • GLACIER GLACIERS MAKE UP MOST OF THE EARTH´S FRESH WATER. GLACIERS ARE MASSES OF ICE CREATED BY ACCUMULATION OF SNOW. THEY ARE FOUND IN POLAR REGIONS AND AT THE TOP OF MOUNTAINS. GLACIERS WHICH REACH THE SEA BREAK AND FORM ICEBERGS. AN ICEBERG A FLOATING MASS OF ICE. TODAY GLACIERS COVER 10% OF THE EARTH´S SURFACE.

16. Science expert Emerald Robinson explains what a lake is (2´) • LAKES Thetragedy of theAral Sea (11´) LAKES ARE PERMANENT MASSES OF WATER WHICH HAVE ACCUMULATED INLAND. WHEN THEY ARE SMALL, THEY ARE CALLED LAGOONS. IF THEIR WATER IS SALT WATER, THEY ARE CALLED INLAND SEAS. THE LARGEST LAKE IN THE WORLD IS CASPIAN SEA.

17. A really short video (2´) in whichEmerald Robinson explainswhat a riveris and howwe can define it • RIVERS OF THE WORLD RIVERS ARE PERMANENT CURRENTS OF WATER. MANY RIVERS START FROM GROUNDWATER WHICH RISES AND FORM SPRINGS. OTHER ORIGINATE FROM GLACIERS OR LAKES OR FROM THE ACCUMULATION OF RAINFALL OR FROM MELTING SNOW.

18. THE COURSE OF A RIVER THE PLACE WHERE A RIVER STARTS IS CALLED ITS SOURCE OR SPRING SMALL RIVERS FLOWING INTO A LARGER RIVER ARE CALLED TRIBUTARIES THE AREA OCCUPIED BY A RIVER AND ITS TRIBUTARIES IS CALLED BASIN THE FLOW OF A RIVER REFERS TO THE AMOUNT OF WATER IT CARRIES

19. FLUVIAL EROSION GORGE WATERFALLS ALLS MEANDERS ALLUVIAL PLAIN GLACIER DELTA RIV ERS TRAVEL FAST DOWN STEEP SLOPES. THEY ERODE MATERIALS, AND CREATE DEEP VALLEYS AND CANYONS WHEN THE SLOPES ARE GENTLER, THE WATER MOVES MORE SLOWLY. IT TRANSPORT THE ERODED MATERIALS. WHEN RIVERS ARRIVE AT THE FLATTER LANDS WHICH ARE NEAR THE SEA, THE Y DEPOSITE SEDIMENT ON THEIR BANKS. THESE AREAS ARE KNOWN AS ALLUVIAL PLAINS UPPER COURSE CANYON MIDDLE COURSE LOWER COURSE

20. THE COURSE OF A RIVER

21. GROUNDWATER AND AQUIFERS RAINWATER THAT INFILTRATES ROCKS AND THE SOIL CAN BE FOUND AS GROUNDWATER UNDER THE EARTH´S SURFACE AQUIFERS ARE STORES OF GROUNDWATER THAT ACCUMULATE UNDERGROUND ON TOP OF IMPERMEABLE LAYERS OF ROCK. INFLITRATION SPRING AQUIFER WE USE WELLS TO BRING THIS WATER TO SURFACE GROUNDWATER MAKES UP ABOUT 20% OF THE EARTH´S FRESH WATER This 5´long video helpsustounderstandtheimportance of grroundwater

22. SHORTAGE POLLUTION GROUP THINKING MANY KINDS OF HUMAN ACTIVITY AFFECT THE QUALITY OF OUR WATER: CHEMICAL AND PESTICIDES WASTE SEWAGE RADIACTIVE WASTE ACID RAINº • WHAT PROBLEMS ARE RELATED TO WATER TODAY? FLOODS DROUGHTS THERE MAY BE FLOODS IN SOME TROPICAL REGIONS BECAUSE OF THE SAMOUNTS OF WATER THAT FALLS THERE IN A SHORT PERIOD OF TIME . HOWEVER, WATER IS EXTREMELY SCARCE IN VERY DRY REGIONS

23. ANY QUESTIONS?