apes chapter 3 – science, systems, matter, energy€¦ · · 2013-01-30all of these are in...
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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.
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