Learning Objective – you should

know:

Scientific methods, critical thinking

Definition of systems

Positive/Negative feedback in systems

Concepts of energy transfer, energy quality, and forms of energy,

Conservation of Matter and relationship to environmental impacts and pollutants

Laws of Thermodynamics and relationship to environmental impacts

Concepts of energy throughput in systems

How to be a good scientist

human

When faced with new information you need to:

Critically evaluate what you are being fed

Gather information

Understand key concepts and terms

Question how the information was obtained

Question the conclusion that was reached

Consider if the investigator started with valid assumptions

– was he/she biased?

Are the findings in new (frontier) areas or in areas where

there is current consensus?

Make your own decisions to accept or reject ideas.

What to review ‘cause we’re

not!

All of these are in Chapter 3

Scientific Method

Basic Chemistry

States of Matter

Methods of Energy Transfer

The EM spectrum

The concept of feedback is important in environmental science.

Try to follow the ideas listed here and develop an understanding

For the differences between positive and negative feedback.

Hyperlinks have been added to supplement and support these concepts.

Follow them for greater understanding.

Systems

Systems are a set of components that

function and interact together

and

Can be isolated for individual study

Earth is a System – a big one, but a

system.

Parts of a System

Inputs – in our context this is energy,

resources (matter) or information.

Flows or throughputs – movement of

the inputs at specific rates.

Stores – temporary or longer-term

accumulations of the inputs within a

component of the system.

Outputs – matter, energy, or information

that the system releases into sinks in the

environment.

Systems Operation

Systems change due to feedbacks.

Often feedbacks “loop” back into the

system from which they originated and

cause a change in the systems actions.

Positive Feedback – a change that causes a

system to change further in the same

direction.

Negative Feedback – a change that causes

a system to decrease the amount of change

it has in the same direction (reverse

direction)

Positive Feedback Loop

Climate

Warms CO2

Permafrost

melts

Additional CO2

is released

• Power plants produce CO2

• CO2 causes warming.

• With warming, permafrost melts,

causing additional CO2 to be

released from tundra soils

• This causes further acceleration

of warming. The hyperlink takes you to a short article about the effects of warming on

turndra, including the release of CO2 into the atmosphere.

Negative Feedback Loop

Climate

Warms CO2

• Power plants produce CO2

• CO2 causes warming.

• With warming, glaciers and ice

melt and cold water enters the

oceans

• This cools ocean waters and

alters ocean current patterns.

• Earths heating patterns change.

• Earth cools

• A new ice age starts.

Glaciers

Melt

Cold water

enters

oceans

Ocean

currents

cool

Note – this is an example of

one feedback that may or

may not operate as stated.

There is much disagreement

on this outcome. It does

make a good example though.

You read a short article about

Yellowstone and wolves.

How did you describe the feedback

loop of the positive and

negative feedback that occurs in the

Yellowstone Ecosystem as a result of

the re-introduction of wolves.

Concept – Energy Quality

The ability of energy to do useful work.

High Quality Energy – a concentrated form

that is capable of doing work

○ Sunlight, coal, petroleum, high temperature

steam, etc.

Low Quality Energy – dispersed energy, less

capable of doing work

○ Low temperature water (100 C), waste heat

from other processes

The Law of Conservation of

Matter

Matter can be neither created nor

destroyed

We can never “throw anything away” – even

if a substance breaks or changes form, the

matter (at some level) still exists.

This has critical implications in the

environment

In some cases, toxins simply don’t quit being

toxic, but they may become even more

dispersed through the environment.

Laws of Thermodynamics

1st Law: Energy is neither created nor

destroyed but it can be converted from

one form to another

2nd Law: When energy changes form,

some of the useful energy is always

degraded to a lower quality, less useful

form (usually low qualilty heat).

Connecting Concepts - Energy

High

Quality

Energy

“Burns”

Energy

Converts

Form

Matter

Conserved

Low

Quality

Heat

Energy

“Inputs” “Conversion” “Outputs”

1st Law 2nd Law

Example – Combustion of Methane

CH4 + 2O2 CO2 + 2H20 (+heat)

Chemical Equation is Balanced

Energy Conversion in Nature

1st Law – No energy is lost, it

changes forms

(Photosynthesis, biomass)

2nd Law – Lower

quality energy - cellular

respiration causes loss

of heat, CO2 . Some

energy is now stored

as potential energy for

future use by whatever

eats the beans.

Application of Thermodynamics

to Economies and Environment

Inputs Throughputs Outputs

Energy Goods Low Quality

and Energy

Services Natural Waste and

Resources Industrial

by-products

(Pollution)

Note that the goods and services are throughputs, not outputs