Water and Water Use IWater and Water Use I

Dihydrogen MonoxideDihydrogen Monoxide

Dihydrogen Monoxide (DHMO) is a colorless and Dihydrogen Monoxide (DHMO) is a colorless and odorless chemical compound, also referred to by some odorless chemical compound, also referred to by some as Dihydrogen Oxide, Hydrogen Hydroxide, as Dihydrogen Oxide, Hydrogen Hydroxide, Hydronium Hydroxide, or simply Hydric acid.Hydronium Hydroxide, or simply Hydric acid.

Some dangers related to DHMO: 1) death due to Some dangers related to DHMO: 1) death due to accidental inhalation, even in small quantities; 2) major accidental inhalation, even in small quantities; 2) major component of acid rain; 3) gaseous DHMO can cause component of acid rain; 3) gaseous DHMO can cause severe burns; 4) found in biopsies of pre-cancerous severe burns; 4) found in biopsies of pre-cancerous tumors and lesions.tumors and lesions.

Dihydrogen MonoxideDihydrogen Monoxide

In spite of its potential dangers, DHMO is still an In spite of its potential dangers, DHMO is still an additive in baby food products, is found in medicines, additive in baby food products, is found in medicines, and common products such as beer and shampoo, and it and common products such as beer and shampoo, and it is a major industrial solvent. is a major industrial solvent.

It is known that regular ingestion of DHMO may It is known that regular ingestion of DHMO may improve athletic performance. However, over use of improve athletic performance. However, over use of DHMO may lead to: 1) excessive sweating; 2) excessive DHMO may lead to: 1) excessive sweating; 2) excessive urination; 3) a bloated feeling; 4) nausea; 5) vomiting; urination; 3) a bloated feeling; 4) nausea; 5) vomiting; and 6) an electrolyte imbalance.and 6) an electrolyte imbalance.

So why is DHMO still made available to humans? So why is DHMO still made available to humans?

Dihydrogen MonoxideDihydrogen Monoxide

Because we cannot survive without dihydrogen monoxide – WATER!!!

Potential Test QuestionsPotential Test Questions:

1.1. Draw a diagram of a water molecule, indicating the regions Draw a diagram of a water molecule, indicating the regions of partial positive and partial negative charges and how of partial positive and partial negative charges and how hydrogen bonds form between adjacent water molecules.hydrogen bonds form between adjacent water molecules.

2.2. Discuss the properties of water related to its being a polar Discuss the properties of water related to its being a polar molecule.molecule.

3.3. Discuss the types of locations where fresh water may be Discuss the types of locations where fresh water may be found. Which of the fresh water sources is available for found. Which of the fresh water sources is available for human consumption?human consumption?

Potential Test QuestionsPotential Test Questions:

4.4. Relate some of the problems caused by overdrawing Relate some of the problems caused by overdrawing surface water and aquifer depletion for the following: the surface water and aquifer depletion for the following: the Colorado River basin, Mono Lake, and the Ogallala Colorado River basin, Mono Lake, and the Ogallala Aquifer.Aquifer.

5.5. What is channelization? Discuss the negative effects of What is channelization? Discuss the negative effects of channelization on habitat diversity, fresh water availability, channelization on habitat diversity, fresh water availability, and flooding.and flooding.

What is Water So Versatile?What is Water So Versatile?

TermsTerms

Specific HeatSpecific Heat - amount of heat energy (calories) required to - amount of heat energy (calories) required to raise 1 gram of water 1 degree C. Water is the standard for raise 1 gram of water 1 degree C. Water is the standard for determining specific heat and defining calories.determining specific heat and defining calories.

HydrophilicHydrophilic ("water-loving") - substances that have a polar or ("water-loving") - substances that have a polar or

ionic nature (e.g., salt crystals; paper- many OH groups, ionic nature (e.g., salt crystals; paper- many OH groups, and water soaks in easily).and water soaks in easily).

HydrophobicHydrophobic ("water-fearing") - substances do not have a ("water-fearing") - substances do not have a polar structure (e.g., oils and waxes).polar structure (e.g., oils and waxes).

Structure of Chemical BondsStructure of Chemical Bonds

Atoms in chemical compounds, such as water, are combined Atoms in chemical compounds, such as water, are combined by either ionic bonds, polar bonds, or non-polar bonds. by either ionic bonds, polar bonds, or non-polar bonds.

Each of these different types of bonds relates to the degree to Each of these different types of bonds relates to the degree to which electrons are shared by the combining atoms.which electrons are shared by the combining atoms.

The degree of electron The degree of electron sharing or transferring is sharing or transferring is influenced by the influenced by the principle that chemical principle that chemical interactions are most interactions are most stable when the outer stable when the outer electron shell of atoms is electron shell of atoms is either filled or emptied.either filled or emptied.

Structure of Chemical Bonds - IonicStructure of Chemical Bonds - Ionic

Structure of Chemical Bonds - Structure of Chemical Bonds - CovalentCovalent

Structure of Chemical Bonds - Structure of Chemical Bonds - CovalentCovalent

InIn non-polar covalent bonds the electrons are shared non-polar covalent bonds the electrons are shared fairly equally among the atoms of the compound. In fairly equally among the atoms of the compound. In polar covalent bonds (e.g., between hydrogens and polar covalent bonds (e.g., between hydrogens and oxygen in water) the oxygen in water) the electrons are not equally shared between the atoms within a molecule, causing unequal distribution of charge.

Water Polar Covalent BondsWater Polar Covalent Bonds

Hydrogen Bonding of WaterHydrogen Bonding of Water

Hydrogen bonds - weak Hydrogen bonds - weak attractive forces between attractive forces between molecules.molecules.

Attractive forces due to uneven Attractive forces due to uneven distribution of electrons in polar distribution of electrons in polar bonds.bonds.

Qualities of Water Because It Is A Qualities of Water Because It Is A Polar MoleculePolar Molecule

1. Cohesion and adhesion2. High heat holding capacity3. Expansion upon freezing4. Universal Solvent

Properties of Properties of Water Related Water Related to Hydrogen to Hydrogen

BondingBonding

Cohesion – attraction Cohesion – attraction among water among water molecules.molecules.

Adhesion – attraction Adhesion – attraction between water between water molecules and other molecules and other molecules.molecules.

Cohesion and AdhesionCohesion and Adhesion

Cohesion and adhesion of Cohesion and adhesion of water produces: 1) surface water produces: 1) surface tension and 2) capillary tension and 2) capillary action.action.

Mechanism by which plants Mechanism by which plants draw water upward from draw water upward from roots to leaves through small roots to leaves through small vessels. Mechanism by vessels. Mechanism by which water moves through which water moves through groundwater reservoirs groundwater reservoirs between the particles of between the particles of rock.rock.

Water Movement in PlantsWater Movement in Plants

Cucumber stem in cross Cucumber stem in cross section showing vascular section showing vascular bundles that convey water bundles that convey water by capillary action.by capillary action.

Water Movement in PlantsWater Movement in Plants

Surface TensionSurface Tension

High Heat Holding CapacityHigh Heat Holding Capacity

1.1. Water has a high boiling point, so water is a liquid over a Water has a high boiling point, so water is a liquid over a wide temperature range.wide temperature range.

2.2. Water has the ability to absorb much heat, so large bodies Water has the ability to absorb much heat, so large bodies of water can minimize temperature changes.of water can minimize temperature changes.

3.3. Water produces evaporative cooling. The heat loss Water produces evaporative cooling. The heat loss associated with evaporation makes evaporation an associated with evaporation makes evaporation an effective way for organisms to shed excess effective way for organisms to shed excess heat.

Expansion of Water Upon FreezingExpansion of Water Upon Freezing

Floating ice insulates the water below and prevents seas Floating ice insulates the water below and prevents seas and lakes from freezing solidand lakes from freezing solid.

Liquid Water is More Dense Than IceLiquid Water is More Dense Than Ice

Water Temperature and LakesWater Temperature and LakesAquatic organisms are subjected to less temperature variation Aquatic organisms are subjected to less temperature variation

than terrestrial organisms. Also, the extremes are not as than terrestrial organisms. Also, the extremes are not as great and the rate of change is much slower than on land.great and the rate of change is much slower than on land.

Thermal Stratification Thermal Stratification - waters become layered by - waters become layered by temperatures. This usually occurs in lakes deeper than 7 temperatures. This usually occurs in lakes deeper than 7 meters (25 ft), with lake morphology and wind important. meters (25 ft), with lake morphology and wind important.

Water Temperature and LakesWater Temperature and Lakes

Spring and Fall OverturnsSpring and Fall Overturns - very important in temperate - very important in temperate zone lakes. zone lakes.

Ex = Spring Overturn (circulation) where initially under Ex = Spring Overturn (circulation) where initially under winter conditions are such that temperatures increase winter conditions are such that temperatures increase below ice from near 0 at the surface to about 4C at the below ice from near 0 at the surface to about 4C at the bottom (stratified by density). The ice melts and surface bottom (stratified by density). The ice melts and surface waters warm to near 4 C and begin to sink. Continues waters warm to near 4 C and begin to sink. Continues until whole lake is homothermous (sameuntil whole lake is homothermous (same temperature).temperature).

Results in mixing of deeper, nutrient-rich water with Results in mixing of deeper, nutrient-rich water with surface, nutrient-poor water.surface, nutrient-poor water.

Water Temperature and LakesWater Temperature and Lakes

Water As The Universal SolventWater As The Universal Solvent

Water is the medium Water is the medium in which all of life’s in which all of life’s chemical reactions occur.chemical reactions occur.

Compounds necessary Compounds necessary for living cells (nutrients, for living cells (nutrients, sugars, amino acids, etc.) sugars, amino acids, etc.) can be dissolved in water, can be dissolved in water, the solution of a cell.the solution of a cell.

Water As The Universal SolventWater As The Universal Solvent

pHpH

pH measures the hydrogen pH measures the hydrogen ion concentration of a ion concentration of a solution. It is measured on a solution. It is measured on a logarithmic scale (i.e., logarithmic scale (i.e., number change is a factor of number change is a factor of 10x the previous number).10x the previous number).

The higher the HThe higher the H+ +

concentration the lower the concentration the lower the pH number.pH number.

AcidsAcids donate H donate H+ + , while , while basesbases accept Haccept H+ .+ .

Instead of Terra, we should call the earth Aqua because Instead of Terra, we should call the earth Aqua because water is its outstanding feature.water is its outstanding feature.

Hydrologic CycleHydrologic CycleContinually distills and distributes water through the Continually distills and distributes water through the processes of evaporation and transpiration, precipitation, processes of evaporation and transpiration, precipitation, surface runoff and infiltration, and ground water movement.surface runoff and infiltration, and ground water movement.

Hydrologic CycleHydrologic CycleContinually distills and distributes water through the Continually distills and distributes water through the processes of evaporation and transpiration, precipitation, processes of evaporation and transpiration, precipitation, surface runoff and infiltration, and ground water movement.surface runoff and infiltration, and ground water movement.

RainfallRainfall

Earth’s Water CompartmentsEarth’s Water Compartments

Earth's water compartments-estimated volume of water in storage(thousands ofkm3), percent of total, and average residence time.Category Volume % Total Water Residence TimeTotal 1,403,377 100 2,800 yearsOcean 1,370,000 97.6 3,000/30,000 yearsIce and snow 29,000 2.07 1 to 16,000 yearsGroundwater 4,000 0.28 Days to 1000s yrsLakes/Reservoirs 125 0.009 1 to 100 yearsSaline lakes 104 0.007 10 to 1,000 yearsSoil moisture 65 0.005 2 weeks to 1 yearPlants/Animals 65 0.005 1 weekAtmosphere 13 0.001 8 to 10 daysSwamps/marshes 3.6 0.003 Months to yearsRivers and streams 1.7 0.0001 10 to 30 days

Earth’s Water Earth’s Water CompartmentsCompartments

Freshwater ResourcesFreshwater Resources

Water Water UseUse

Per-capita Water UsePer-capita Water Use

1 cubic meter = 264 U.S. gallons 1 cubic meter = 264 U.S. gallons

~1,300 gallons/day

How Much Water Is Needed Per How Much Water Is Needed Per PersonPerson

The average person needs a minimum of The average person needs a minimum of 1.3 gallons (5 liters) of water per day to 1.3 gallons (5 liters) of water per day to survive in a moderate climate at an survive in a moderate climate at an average activity level.average activity level.

The minimum amount of water needed for The minimum amount of water needed for drinking, cooking, bathing, and sanitation drinking, cooking, bathing, and sanitation is 13 gallons (50 liters). is 13 gallons (50 liters).