An illustration of water molecule packing in solid water (ice)

Transcription

1 Prperties f Water The water cycle has always served as nature s principal water purificatin prcess. When water evaprates, cntaminants are left behind. Pure water shuld fall as precipitatin but cntaminants enter the water supply again. Prperties f Water water is called the UNIVERSAL SOLVENT it is able t disslve many different substances clear(transparent), clurless, durless and tasteless high heat capacity means that large bdies f water act as heat reservirs density f 1.0 g/ml but slid water is LESS dense than liquid water (thus, ice flats n water acting as an isulatr) An illustratin f water mlecule packing in liquid water. An illustratin f water mlecule packing in slid water (ice) A side view illustrating the spaces between the mlecules.

2 Water is a plar mlecule Diples allw intermlecular frce called HYDROGEN BONDING, allwing water mlecules t be mre tightly held tgether Melting pint/ freezing pint f 0 C and biling pint f 100 C water is a liquid at rm temperature water has a high biling pint because lts f energy is required t break H bnds Able t disslve ther plar mlecules and inic cmpunds Since water is such a gd slvent, water can easily becme cntaminated with a great variety f substances GROUND WATER water that seeps undergrund and cllects in aquifers Impurities in sil and rck add irn, zinc, magnesium and calcium t water SURFACE WATER water in lakes, pnds, rivers and streams Primary surce f drinking water

3 Water Cycle Answer Key Vcabulary: aquifer, cndensatin, evapratin, freezing, glacier, melting, phase change, precipitatin, reservir, runff, transpiratin, water cycle Prir Knwledge Questins (D these BEFORE using the Gizm.) 1. When yu turn n a water faucet, where des the water cme frm? Mst drinking water is piped in frm artificial reservirs. 2. Animals and plants have been using water fr millins f years. Why dn t we run ut? Water is cntinually recycled thrughut the planet. Eg. Plants and animals release water back int the air and sil when they breathe and ecrete wastes. Water is als returned t sil when plants and animals die and decmpse. Gizm Warm-up Water n Earth is always in mtin. These mtins frm a repeating circuit called the water cycle. The Water Cycle Gizm allws yu t eplre the different paths water takes as it mves frm Earth s surface t the atmsphere and back. 1. Click Oceans. What percentage f Earth s water is fund in the ceans? 97.25% 2. Click Atmsphere. Hw des water get t the atmsphere? By evapratin 3. Click Cluds. Hw d cluds frm? Water vapr in the atmsphere cls and cndenses. 4. Click Precip (rain). ( Precip is shrt fr precipitatin, r water falling t Earth s surface.) What causes it t rain? Rain ccurs when water drplets in cluds are large enugh t fall. 5. Click Oceans again, and then chse the PATH tab. Because it has the same beginning and end, the path is a cmplete cycle. Hw many steps des this cycle have? 5 steps Activity: The water cycle Get the Gizm ready: Select the SIMULATION tab, and click Reset.

4 Questin: What are the parts f the water cycle? 1. Cllect data: Create tw water cycles using the Gizm. Each cycle shuld have at least fur steps and shuld begin and end at the same lcatin. Chse any starting pint frm the list n the right. When the cycle is cmplete, chse the PATH tab and write the steps belw. Cycle 1: _eg. Ocean, atmsphere, cluds, precipitatin, rivers, sil, vegetatins, wildlife, atmsphere, cluds, rain, reservir, persn, wastewater, cean Cycle 2: 2. Analyze: Use the infrmatin presented in the Gizm t answer the fllwing questins. A. What percentage f Earth s water can be fund in sil? 0.005% B. What percentage f Earth s water is stred in ice and snw? 1.9% C. What percentage f Earth s fresh water is stred in ice and snw? 68.7% D. What percentage f Earth s water is fund in lakes? 0.009% E. What is transpiratin? (Hint: Click the Vegetatin buttn.) Plants releasing water vapr frm their leaves. F. What human activity uses the mst water wrldwide? Agriculture (70%) G. What human activity uses the mst water in the United States? Industry (59%) H. What rganisms break dwn chemical wastes in a treatment plant? Bacteria I. What is an aquifer? An aquifer stres water in the grund. J. What is a reservir? A bdy f water (ften a lake) that stres water fr human use. K. In what ways can runff be a prblem? Runff causes flding and ersin and can als wash pllutants int rivers. (Activity cntinued n net page)

5 Activity (cntinued frm previus page) 3. Define: A phase change is a change frm ne state t anther, such as frm a liquid t a gas. Based n what yu have read in the Gizm, fill in the blanks with the wrds liquid, gas, r slid t define each change. Evapratin: Cndensatin: Melting: Freezing: Change frm a liquid t a gas Change frm a gas t a liquid Change frm a slid t a liquid Change frm a liquid t a slid 4. Practice: Fill in the prcess that causes each transitin. Yur chices are evapratin, cndensatin, precipitatin, melting, and freezing. A. Ocean Atmsphere Evapratin B. Atmsphere Cluds Cndensatin C. Clud Snw Freezing D. Glacier (river f ice) River Melting E. Clud Sil Precipitatin 5. Practice: Fill in the tw prcesses that cause each f the fllwing transitins. A. Ocean Clud Evapratin, cndensatin B. Clud Glacier Freezing, precipitatin (r precipitatin, freezing) 6. Think and discuss: Water cvers ver tw-thirds f Earth s surface. Yet water shrtages are a majr prblem fr many peple arund the wrld. Why d yu think this is the case? Answers will vary. There are many acceptable answers t this questin. Sample answer: Over 97% f Earth s water is salt water, which is nt useful fr peple. Mst f the fresh water n Earth is lcked up in glaciers and ice caps, s it cannt be used either. Only abut 1% f Earth s water is available fr human use. Many parts f Earth are very dry, and there is nt enugh water fr agriculture, industry, and human cnsumptin. Sme peple use ecessive amunts f water, leaving less fr thers t use.

6 Assessment Questins (5): 1. Which f the fllwing cntains the largest percentage f the Earth's water? A. Atmsphere B. Oceans C. Ice/Snw D. Vegetatin 2. What is the defining characteristic f a water cycle? A. The water passes thrugh at least five different lcatins. B. It des nt include any human water usage. C. It passes thrugh plants, animals and the cean. D. It has the same starting and ending pint. 3. What human activity uses the mst water, wrldwide? A. Drinking B. Industry C. Agriculture D. Bathing 4. Where is the majrity f the Earth's fresh water stred? A. In glaciers and icecaps B. In lakes C. In plants D. In the atmsphere 5. What sequence f prcesses transprts water frm the cean int a clud? A. Evapratin and cndensatin. B. Cndensatin and freezing. C. Precipitatin and cndensatin. D. Evapratin and precipitatin.

7 GIZMO: Water Pllutants Tic Sediment Nutrient Bacteria Eplanatin Materials that cause DEATH, DISEASE and BIRTH DEFECTS in rganisms that ingest them Eamples Paint, gas, battery acid, mercury, pesticides Cnsists f SOIL, SAND and MINERALS washed frm land int water after rain. Sediments pile up in reservirs, rivers and harbrs, destry fish and wildlife habitat and clud the water s that sunlight cannt reach aquatic plants. Careless farming, mining and building activity epses sediment material Cntaminatin f water resurces by ecessive amunts f nutrients. A nutrient is a substance used by living things t prmte grwth (eg. Nitrgen and phsphrus) T many nutrients causes ecess algal prductin, reducing the amunt f sunlight entering lakes, rivers. Ecess fertilizer, manure and human waste. Micrscpic living rganisms that can help with pllutin cntrl by breaking dwn rganic matter in sewage, il spills and ther pllutants. Sme bacterial in sil, water and air can cause human, animal and plant health prblems. Animal manure, imprper fd handling and human waste. Eample Tic Sediment Nutrient Bacterial Effect Farmer dumps chicken manure int nearby river. Several trips t the grcery stre instead f ne. Using lts f pesticides and nt rtating crps. Manure cntains bacteria causing illness; nutrients can cause algae vergrwth Car ehaust and fluids are tic; nitrgen ide can cause nutrient prblems Pesticides are tic t many animals.

8 Chpping dwn trees t build mvie theatre. Dumping car il and antifreeze in an alley. Chpping dwn shrubs and trees. Putting paint and slvents int a garbage bag. Using t much water in shwers and in tilets. Fds individually packaged with paper prducts. Subdivisin with a parking lt/ park beside water. Overfertilizing yur lawn. Leaking r verflw in septic tanks. Wind and rain will erde sil causing sediment t build-up in nearby waterways Tic t land and water animals. Sil will erde leaving t much sediment in the river. Tic chemicals can leak during transprt r cntaminate sil and water at landfill site. Ecess sewage ges int waterways untreated bacteria can cause illness and ecess nitrgen will cause algal grwth. Mre paper = mre trees cut dwn leading t sil ersin Chemicals frm cars will leak int water supply; ersin will ccur while subdivisin is being built. Unused fertilizer washes away with the rain causing etra nutrients in nearby waterways. Human waste cntains bacteria causing sickness and high nitrgen cntent leading t nutrient pllutin.

9 4.2 What s in Clean Water? Bttled water cmes frm: Tap water that is reprcessed by DISTILLATION (water is vaprized and then cndensed) this is pure H 2 O Undergrund springs and wells - this is water that seeps thrugh sil and rck and therefre cntains many disslved ins. Ins can be fund in drinking water that are: i) helpful eg. Fe +2, Fe +3, and Mg +2 ins lw cncentratins f these ins give water flavur and benefit human health ii) harmful S -2 has a bad dur T many Fe ins gives bad taste Heavy metals are dangerus fr health cancer, mutatins/defects Hard water Refers t water that cntains many disslved minerals (eg Ca +2, Mg +2,,Fe +2, Fe +3, and Mn +2 ) Hard water causes: Bathtub ring Scale depstis n heating devices Reduces the sudsing ability f saps Water can be sftened by: Adding sdium carbnate r sdium heametaphsphate The sda-lime prcess in used in sme municipalities in Ontari sda (sdium carbnate) and lime (calcium hydride) are added t remve Ca +2 and Mg +2 ins ILLUSTRATION: Disslved ygen The amunt f ygen in water is als mnitred as it affects what is able t survive in the water. T little ygen results in the death f many large fish and decreases aquatic diversity. 3 min vide n municipal drinking water treatment vide n wastewater treatment

10 4.3 What s in Plluted Water? In the activity last day, we lked at several types f pllutants. These can be further classified as belw. Type f pllutant Physical cntaminants Bilgical cntaminants Chemical cntaminants Definitin Eamples Methd f remving frm water Objects that Oil and Remval by d nt petrleum screens disslve in prducts Sme less dense water Garbage chemicals can Tree branches be skimmed ff Silt, clay, sil Sand filtratin (als called Flcculatin sediment) Bacteria and E. cli bacteria Adding chlrine kills viruses frm agricultural bacteria (farm) runff r Substances that are sluble in water (disslve) human waste Manufactured chemicals Metal ins and cmpunds (Pb, Hg, Cd) Pesticides Fertilizers Sluble petrleum prducts salts Sme chemicals degrade naturally Bacteria are able t break dwn sme chemicals Sme may nt be remved and remain tic t plants,animals and humans Ways yu can help with the water pllutin prblem 1. Schl labratry Any unsafe chemicals are cllected fr special hazardus waste dispsal. 2. At hme Husehld hazardus wastes (cleaners, paints, batteries) anything labeled CORROSIVE, FLAMMABLE, REACTIVE r TOXIC shuld be brught t designated hazardus waste facility.

11 4.6 Case Study: Prtecting Canada s Great Lakes Envirnment 1. a) What are the three main gals f the Great Lakes Actin Plan? T establish a healthy envirnment T prtect the health f citizens T sustain cmmunities b) List the seven specific bjectives required t meet thse gals. T restre areas f cncern T cnserve eclgically imprtant areas T cntrl the intrductin f etic species T advance sustainable use f the Great Lakes Basin T reduce harmful pllutants T assess and manage ecsystem health 2. a) What is an AOC? Why are they a cncern? AOC = area f cncern In these areas, pllutants frm industrial surces, sewage treatment plants, landfills, and agricultural runff have entered the waterways, destryed the quality f the water, and created unsafe situatins fr peple and wildlife b) What is an RAP? - RAP = remedial actin plan - a plan designed t restre the eclgical health f an area and t make recreatinal use pssible - identifies cntaminants & surces, treatment needed t clean the water, preventative measures t relieve future cntaminatin 3. a) Identify and eplain ne reasn fr the success f the RAP fr Hamiltn Harbur. - success was achieved because gvernment, envirnmentalists, business peple, peple frm industries, and cncerned individuals wrked tgether t slve the prblem b) Eplain the Yellw Fish prgram - t raise awareness abut the impact f tic substances n lcal waters, participants paint yellw fish symbls beside strm drains t remind peple nt t pur harmful, hazardus materials ( il, cleaners, paints, pesticides, prducts with warning labels, sap) dwn the drains c) Describe tw eamples f evidence f the successful restratin f Hamiltn Harbur. - peple are swimming in the harbur - public access t the harburfrnt has been imprved - fish ppulatins are increasing d) Give tw ways that human health has benefited frm the restratin f the harbur? - reducing epsure t cntaminants - health and well-being are increased by habitat restratin, imprvement f water quality, rehabilitatin f shrelines and creatin f shreline trails

12 Great Lakes: Trubled Waters(90056) 1. List sme f the chemicals that are plluting the Great Lakes and their surces. Pesticides Plastic PCB s Diins Mercury, silver, lead, arsenic Sewage Industrial waste Waste frm pulp mills cyanide 2. Give three ptins chemists have regarding chemical pllutants. i) stp using chemicals ii) invent ther chemicals t break dwn harmful substances iii) use different chemicals 3. What is an AOC? Give an eample f ne. AOC = area f cncern Eample: Great Lakes epsed t hazardus wastes and sewage Arund the Great Lakes there are 42 AOC s since mre businesses and peple are lcated clse t the water. 4. Hw can the amunt f pllutin in water be measured? Mnitring wildlife mnitr numbers f animals/birds/insects; mnitr reprductin rates, mnitr eggs Mnitr tumrs and cancer in fish Chemical analysis directly measure chemicals in the water 5. Cmplete these statements: a. What we d with the envirnment tday, will cme back t haunt us tmrrw. b. Dilutin is nt the slutin t pllutin.

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