10/1/13Agenda: Chapter 8 Quiz Importance of

Water Practice FRQ

Life’s Work:Read ch. 11 and study for quiz Friday

Objective: SWBAT describe the characteristics

and importance of the hydrologic cycle.

Due Now: Ocean Zones chart,Freshwater questions

Do Now:Practice AP FRQ: Be prepared to grade your own! You don’t have to write the question.

List and describe four ways that humans impact freshwater ecosystems.

Score Your Own FRQ4 points total

Describe FOUR ways that humans have affected freshwater ecosystems, not just list; 1 point for each described; score only the first four.

Deejays suspended for "dihydrogen monoxide" April Fools jokeMark Frauenfelder at 7:25 am Thu, Apr 4, 2013

Jim Leftwich says: "Two Deejays for "Gator Country 101.9" warned that 'dihydrogen monoxide' was coming out of peoples' water faucets. Georgians panicked.

“Water is the driver of nature.”

- Leonardo da Vinci

Without water, the other nutrient cycles would not exist in their present forms, and life on earth could not exist.

What Makes Water so Special?Unique Properties of H2O

Property Why it MattersHydrogen bonds: there are strong forces of attraction between molecules of water.

It takes lots of energy to vaporize (evaporate) water.

Heat capacity: water changes temperature very slowly because it can store heat.

This protects living organisms from the shock of abrupt temperature changes

Polar structure (one positive end, one negative end): water can dissolve a wide variety of compounds.

Water can easily become polluted by water-soluble wastes.

Expands when freezes Ice has a lower density than liquid water, so continental ice shelf floats on water.

Why is Water Important? Water keeps us alive, moderates

climate, sculpts the land, removes and dilutes wastes and pollutants, and moves continually through the hydrologic cycle.

Only about 0.02% of the earth’s water supply is available to us as liquid freshwater.

How Do We Use Water?70% Irrigation:

watering crops20% Industry:

cooling down power plants

10% Domestic and Municipal: drinking, sewage, bathwater, dishwater, & laundry

So Do We Use Water Responsibly?We currently use more than half of

the world’s reliable runoff of surface water and could be using 70-90% by 2025.

About 70% of the water we withdraw from rivers, lakes, and aquifers is not returned to these sources.

Why does this matter? There is only a limited amount of water available on Earth!

Fig. 14-3, p. 308

Unconfined Aquifer Recharge Area

Precipitation Evaporation and transpiration Evaporation

Confined Recharge Area

Runoff

Flowing artesian well

Recharge Unconfined Aquifer

Stream Well requiring a pumpInfiltration Water

table LakeInfiltration

Unconfined aquiferConfined aquifer

Confining impermeable rock layer

Less permeable material such as clay

Hydrologic Cycle BasicsPrecipitation (rain, snow, sleet, hail)

Some infiltrates the ground and is stored in soil

and rock (groundwater)

Some runs off into

bodies of water

(surface runoff)

Land from which the

surface water drains into a

body of water is called its

watershed or drainage

basin

Some evaporates from

the ground

Surface Water Comes from precipitation Examples: streams, rivers, and lakes Watershed flow: small streams

larger streams rivers sea Tributary: river or stream flowing into

a larger river or stream

Freshwater Streams and Rivers:From the Mountains to the Oceans

Water flowing from mountains to the sea creates different aquatic conditions and habitats.

Figure 6-17

Headwater StreamA narrow zone of cold, clear water

that rushes over waterfalls and rapids.

Large amounts of oxygen are present.

Fish are also present. Ex. trout.

DownstreamSlower-moving waterLess oxygenWarmer temperaturesLots of algae and cyanobacteria.

Groundwater Aquifers: porous rock with water flowing through Water Table: the level of earth’s land crust to

which the aquifer is filled Renewability: the circulation rate of groundwater

is slow (300 to 4,600 years). Why is knowing renewability rates important?

Practice AP FRQ (16 minutes)2002 - #2

On a separate sheet of paper, complete questions (a) and (b).

Be prepared to grade your own response.

Do not use your notes.