HYDROSPHERE - INTRODUCTION TODAY: 1.What is the Hydrosphere? 2.Likely exam questions. 3.The Global Hydrological Cycle.

1. WHAT IS THE HYDROSPHERE? Earth’s surface waters. WHY DO WE LOOK AT THE HYDROSPHERE? Water is one of the most important resources on the planet. Unevenly distributed but crucial resource. Water also has the power to shape the landscape over long periods of time / shorter bursts of activity. Water is life-giving and life-threatening.

HYDROSPHERE Starting Point: a.Earth’s Water. b.Distribution of fresh and salt water.

Earth's Water and the Hydrologic Cycle

HYDROSPHERE 2. Likely exam questions: –OS Map question or explanations of how river features (i.e waterfalls, ox bow lakes) are formed roughly every 2 years –Every 3/4 years questions about the Hydrological Cycle and River Flow data (river regimes etc)

3. THE GLOBAL HYDROLOGICAL CYCLE You should be able to: 1.Draw a diagram highlighting the main elements of the cycle 2.Describe the global hydrological cycle as shown on a diagram 3.Explain how the balance is maintained within the cycle You may have come across the Global Hydrological Cycle in Biology

THE GLOBAL HYDROLOGICAL CYCLE Moist air moves upwards, begins to cool and condense Precipitation returns water to the Earth’s surface. Most water runs off the surface but some percolates through the soil and travels underground to seas and oceans Water converted into vapour by evaporation and transpiration

Write definitions for these key terms (use text book p.38 onwards) Hydrological cycle Condensation Infiltration Groundwater zone Evaporation Precipitation Throughflow Surface runoff Transpiration Storage Percolation Closed system

Homework: THE GLOBAL HYDROLOGICAL CYCLE Copy fig 3.2 p. 39 and using page 38  39: Describe the global hydrological cycle (6-10 marks) With a diagram this question is usually worth between 6 and 10 marks –The Earth contains a finite amount of water –The highest % is stored in the world’s oceans (95%) –Second highest % trapped in ice caps and at the poles –Heat from sun results in evaporation from the oceans –Moist air condenses and precipitation results –Clouds form and transport water –Precipitation may occur as rain or snow depending on altitude –Rainwater returns to oceans and seas via rivers and streams –Water can infiltrate the soil and rocks and return to the system as groundwater flow –Water can also be evaporated from lakes or transpired from vegetation