Chapter 2: Environmental SystemsModule 4: Systems and Matter

A Lake of Salt Water, Dust Storms, and Endangered Species

The story of Mono Lake shows how a change in one factor can have unexpected effects.

Background of Mono Lake Characterized by towers of limestone called tufa (created by evaporation of

water) terminal lake…no output So salty that fish cannot survive…only brine shrimp ad alkali fly larvae Used as a migration stop for birds

Starting in 1941 the lakes health was deteriorating due to water diversion of feeder streams....

1. Can cause dust storms2. May contain high amounts of arsenic3. Destroys ecosystem (algae, brine shrimp), harms migratory birds

The health of Mono Lake is recovering due to decreased water diversion from feeder streams. To offset the human need of water…

L.A. needed to reduce water consumption Used xeriscaping (native plants not requiring water rather than grass-

covered lawns) Required low flow shower heads and water-saving toilets

Matter and Atoms

Matter is anything that has mass and occupies space.

Basic Unit is the Atom (made of protons, neutrons and electrons).

An Element is a substance made of one type of atom. Found on the periodic table

Atoms vs. Ions vs. IsotopesAtoms Ions Isotopes

All represent specific ElementsSame number of protons….atomic number

Most common isotopeElectrically neutral

StableGain or lose electrons to get full outer energy level

Varying mass numbers

Radioactivity Radioactive isotopes like U-235 undergo radioactive decay as their unstable

nuclei come apart emitting energy Half-life: time it takes for ½ of the original radioactive “parent” element to

decay Useful….carbon dating

Chemical Bonds

Ionic Polar covalent Nonpolar covalent

Hydrogen

Metal and Nonmetal

Share electrons unequally

Share electrons equally

Weak bond

Electrical

Exchange electrons to form ions

Salt

Sugar, Water Oil, Fats attraction between two polar molecules

Water Properties Unique properties of water make life on Earth possible… Facilitate transfer of chemical elements and compounds from one system to

another Support conditions necessary for life

Due to the polarity of water….

1. Universal solvent: dissolves solutes with the same polarity (polar or ionic)2. Surface tension: due to the cohesion of water; water making hydrogen bonds

with other water molecules; “skin” on top of water3. Capillary action: water moving up a hollow tube; requires water to be

adhesive to “tube”4. High boiling point: allows water to be a solid, liquid and gas in Earth’s temp.

range5. High specific heat: it takes a lot of energy to change water’s temperature6. Water floats as a solid due to its crystalline structure making the molecules

expand as it freezes.

Acids and Bases All acids and bases are aqueous (water-based) solutions

pH scale shows relative strength of acids and bases. Logarithmic….based on the power of 10

o pH of 3 is 10x more acidic then a pH of 4 0-14 Acids….below 7 Neutral…7 Bases…above 7

Acids Bases Dissociates into Hydronium

or hydrogen ions (when dissolved in water)

Start with H- HCl, H2SO4

Dissociates into Hydroxide ions (when dissolved in water)

Ends with –OH or –H NaOH, NH3

Chemical Reactions

Conservation of Matter….matter cannot be created or destroyed Balancing Reactions

Example: Combustion of Propane (C3H8)

Can occur in one or both directions…. Ozone

Combustion releases metals/sulfur associated to fossil fuels into the atmosphere…they deposit somewhere else…no longer tied up in the fossil fuel

Macromolecules Organic vs. InorganicOrganic Inorganic

Contains carbon along with hydrogen

Fossil fuels Carbs, lipids, proteins, nucleic

Does not contain carbon to carbon bonds…does not have carbon along with hydrogen

Salt (NaCl)

acids CO2, H2O

MacromoleculesCarbohydrates Lipids Proteins Nucleic Acids

Monosaccharides like glucose

Sugar Cellulose (cell

walls) Starch

Saturated vs. Unsaturated Fats

Fatty acids Wax Steroids Cholesterol Triglyceride Phospholipids

(cell membranes)

Amino acids Enzymes Peptide

bonds Muscle antibodies

Nucleotides DNA RNA Code of life

Cells Smallest structural and functional component of organisms. Made of Carbohydrates, proteins, lipids, nucleic acids and aqueous solutions

surrounded by a membrane.

Module 4 OUTPUT….

A Lake of Salt Water, Dust Storms, and Endangered Species

Compare and contrast Mono Lake to the Aral Sea…use a Venn Diagram.

Matter and Atoms 1. Complete the Table below. Pg.34

Element Name and Symbol

Atomic Number Mass Number Common substance that

contains the element

Carbon (C)Hydrogen (H)Oxygen (O)Nitrogen (N)Phosphorus (P)Sulfur (S)

2. Draw an atom of Carbon3. Watch the video “How Does Radiocarbon Dating Work?” on Youtube and

write notes on how carbon dating works as well as how it is useful in science. Feel free to watch additional videos.

Chemical Bonds Create cartoons that show differences between different types of chemical bonds.Water Properties Mini-Lab….

For each demo, name the property of water exhibited.1. Pour water into a glass until it forms a slight dome on top. Carefully rest a

paperclip on the surface.2. Drop ice into a clear bottle of water and seal the top. Then turn the bottle

upside down until the ice rises to the water’s surface.3. Drop a couple of drops of dark food coloring into a beaker of water.

Watch as the color dissolves in the water. 4. Dip the edge of a paper towel into the beaker of water in which the food

coloring has been added. Lay the rest of the paper on the table and watch as the water creeps up the paper.

Complete the table below….Property of Water Function in environment

Surface tensionCapillary actionHigh boiling and melting pointsExpands when freezesGood solvent

Acids and Bases Mini-lab Draw the pH scale. Label the portion that represents acids, neutral,

bases. Also label H+ and OH-

Complete the following table….pH

Tap waterTap water after blowing into the water for 30 seconds using a straw

Use the data above to infer why is the pH of rain slightly acidic? Create a picture to help you remember this fact.

Place a piece of chalk (made of Calcium carbonate…similar to limestone and shell fish) in vinegar. Create a visual to display what you observe.

How did pH change? What reaction are you observing? How does this relate to environmental science?

Using Fig.4.7 (pg.39) and the figure below, answer the following questions:

o At what pH range can all selected species survive? Is this acidic, neutral or basic?

o At what pH range do the fewest species survive? Is this acidic, neutral or basic?

o Which species are the most sensitive to acidic environments? How can you tell?

o Which species are the most tolerant of acidic environments? How can you tell?

o Do you think pH is an important factor in determining the health of an ecosystem? Why or why not?

Chemical Reactions Mini-lab1. What happens to wood when it burns?2. What happens to organic matter when an animal decomposes?3. What is the source of plant matter as it grows?

Balance the following reactions….

Macromolecules Create a foldable or chart that illustrates differences between carbohydrates, lipids, proteins and nucleic acids. Be sure to include pictures, monomers, examples, important functions.

Cells Draw an animal cell and a plant cell; label at least 5 parts/organelles in each drawing.

Module 5: Energy, Flows and Feedbacks

INPUT….

Energy What is the difference between energy and power?o Energy is the ability to do work or cause changeo Power is the rate at which work is doneo Energy = power x time……kWh (kilowatt-hours) (seen in a power

bill)o Power = energy/time….kW (kilowatt) (tells the power of the

turbine generating electricity) Basic unit of energy is called a joule (J)

o There are other units of energy….

There is A LOT of math involved in energy in describing energy, work and power (that is why we are doing a lab)

Do the Math (pg. 46)…..Let’s do it together

Forms of Energy Potential vs. Kinetic Potential: stored energy that has not been released yet

o Chemical energy: energy stored in the bonds of compounds Food: fat has more energy than carbs. Fuels: biofuels vs. fossil fuels

o Nuclear energy: energy stored in the nuclei of elements Released as thermal energy (temp.=kinetic)

Kinetic: energy of motion; often generated when potential energy is released

o Temperature: measure of the average kinetic energy of a substance (also called thermal energy)

o Mechanical: moving

Electromagnetic energy Carried by photons Energy depends on wavelength

o Long wavelength=low energyo Short wavelength=high energy

Wavelengths in the visible light spectrum are used by plants for photosynthesis.

Majority of the radiation produced by the sun lies within 250-2500 nm or 2.5 x 10-8 m - 2.5 x 10-6 m

Energy Conversions

Energy cannot be created nor destroyed…therefore it is conserved. Energy is converted from one form to another….efficiency measures how

“good” this conversion is…in other words… the more efficient the conversion the least amount of energy is lost as “waste” heat

Think food chains or driving your car….chemical to mechanical (some lost as heat)

The form and amount of energy in an environment determines what kinds of organisms can live there.

Latitudeo Further away from equator = less energy from sun = less

diversity of life Deep ocean vents lack sunlight….energy comes from chemicals (sulfur)

emitted from vents…supports specialized forms of life (plant-less) that can respire anaerobically

Laws of Thermodynamics

First Law of Thermodynamics Energy cannot be created nor destroyed but it can change from one form

to another

Second Law of Thermodynamics When energy is transformed, the amount of energy remains the same

BUT its ability to do work diminishes. Energy efficiency: ratio of the amount of energy expended to the amount

of energy introduced to the new system (in other words…energy input/energy output)

Uh Oh….Math again….o Calculate the overall energy efficiency of converting coal into

compact fluorescent lighting, which is 20 percent efficient. How does this compare to the overall efficiency of an incandescent light bulb (pg.48)?

Energy Quality: the ease at which an energy source can be used for work High (gasoline) vs. Low (wood)

Entropy: disorder, randomness 2nd law of thermodynamics also says that all systems move toward

randomness rather than toward order unless an input of energy from outside the system creates order.

System Dynamics Why is it important to look at the whole system rather than only the pars of a system?

Need to know how all the parts interact A system is defined by the nature of the interactions and its various

components.Open vs. Closed system

Open Closed Most systems are open Matter and energy are exchanged

across borders Example: a lake interacts with the

surrounding land and atmosphere

Matter and energy exchanges do not occur across boundaries

Example: Biobottles, Underground cave

Inputs and Outputs Inputs: matter and energy coming “IN” to the system Outputs: matter and energy coming “OUT” of the system

Steady State Equilibrium Inputs=Outputs

Feedbacks:Positive Negative

Bad for the system Amplify the change in the

system Example: Polar ice melting,

increasing the albedo effect

Keeps the system at a steady state

Example: Reintroducing the wolves to Yellowstone…predator-prey relationships

Change across space and time Temperature, precipitation, soil composition, topography and altitude vary

among natural systems….they determine the biologics that exist in that region

Studying natural variations helps scientists understand correlations between species distribution and landscape variation.

o Can be used to predict the effect of changes in a given ecosystem

o Give information so that humans can help conserve or mitigate the effects of our impacts

Module 5 OUTPUT….

Energy Who’s Got the Power Lab

Forms of Energy Draw a picture to show difference between kinetic and potential energy.(Optional) Design a lab to test if biofuels or fossil fuels have more chemical energy. If time….Carry it out!!

Energy Conversions

Describe how energy from the sun is able to be used by organisms on Earth. Use a picture to aid in your description. Label the different forms of energy.

Laws of Thermodynamics

1st and 2nd law of thermodynamics: Create a drawing (not a car) that illustrates the fundamental concept that energy can neither be created nor destroyed but can change from one form to another. Be sure to show how efficient the system is.

Energy Quality: List at least 3 other sources of energy other then gasoline or wood….which one do you think has the highest energy quality? Create a visual to aid in your answer.

Entropy: create a visual to depict one of the examples of entropy on page 50

System Dynamics Create a pocket to keep 2 index cards…Label one Positive Feedback Loop and the second Negative Feedback Loop…Write examples on the back of the appropriate card