APES
Chapter 2 Science Review
Environmental “Science”
• Some areas of ES research are experimental
and lab-based
• Most research is field-based, involving the
study of highly complex FEEDBACK LOOPS
• ES research is characterized by
– A focus on CONNECTIONS & INTERACTIONS
– LONG time periods
– SYNERGISTIC connections
Experimental Design
• Problem
– Question to be
answered
• Hypothesis
– Scientifically testable
statement
• Independent or
Manipulated Variable
– The one(s) being tested
or changed
• Dependent or
Responding Variable
– The one(s) being
measured
• Control Group
– No M.V. (for
comparison)
• Constants
– All other variables
influencing the outcome
Precision vs. Accuracy
• Accuracy
– The nearness of a
measurement to an agreed
standard (ex. how close to
1kg is a 1kg standard weight
on a particular balance?)
• Precision
– The degree of reproducibility
and consistency of a
measuring device
throughout multiple
measurements
Energy & Matter
•
•
•
•
•
Fixed amounts of each in the universe
Can be converted interchangeably (e = mc2)
Earth is an “open system” regarding energy
Earth is a “closed system” regarding matter
Energy & Mass Laws
– 1: Energy/Matter cannot be created or destroyed
– 2: Energy is always converted to “lower quality”
forms whenever work is done
High vs. Low Quality Matter
• High Quality Matter
– Concentrated, easy to
extract
• Low Quality Matter
– Dispersed, difficult to
extract
Atomic Structure
• The nucleus is tiny and very dense
• The volume is almost entirely the electron cloud
Nuclear Chemistry Review
• Three types of radiation
– Alpha (He nucleus)
– Beta (electrons)
– Gamma (EMR wave)
• Differences in
penetration
– Alpha (sheet of paper)
– Beta (block of wood)
– Gamma (concrete wall)
Fission and Fusion
• Fission
– 1 nucleus splits into
fragments (chain
reaction)
– Ex. Nuclear reactor
• Fusion
– 2 or more nuclei fuse
together
– Ex. The Sun
Energy Laws
• First Law
– Energy cannot be created
or destroyed, only
transformed or converted
between different forms
• Ex. Solar energy to
chemical energy during
Photosynthesis
– During work, energy “in”
ALWAYS equals energy
“out”
– “You cannot get
something for nothing”
• Second Law
– During work, some
energy is degraded into
lower quality forms
• High Quality (ex. Electricity,
Nuclear Fission)
• Medium Quality (ex. Normal
sunlight)
• Low Quality (ex. Geothermal
heat)
– You always end up with
less useable energy
than you start with
– “You cannot break even”
Electromagnetic Spectrum
pH and Solutions
What is pH?
• pH stands for “Potential/Power of Hydrogen”
• The negative logarithm of the concentration
of hydrogen ions in a solution
• A high number = a very small concentration
of H+ ions in solution
• A low number = a very high concentration of
H+ ions in solution
• Logarithmic scale = each number on the
scale represents 10x more or less H+
Elements Important to the
Study of Environmental Science
Ions Important to the Study of
Environmental Science
Types of Pollution
• Degradable
– Ex. Human sewage, organic matter
• Persistent
– Ex. DDT, certain plastics, laminates
• Non-degradable
– Ex. heavy metals, lead & mercury
Through-Put Economies
• High Through-Put Economy
– High consumption of both matter and energy
• Matter Recycling Economy
– Reduced matter consumption
– Still very high energy consumption
• Low Through-Put Economy
– Reduced matter and energy consumption
– Is this possible to achieve?
Inputs, Throughput, and
Outputs of an Economic System
Core Case Study: Carrying Out a
Controlled Scientific Experiment
• F. Herbert Bormann, Gene Likens, et al.:
Hubbard Brook Experimental Forest in NH
(U.S.)
• Compared the loss of water and nutrients
from an uncut forest (control site) with one
that had been stripped (experimental site)
The Effects of Deforestation on the
Loss of Water and Soil Nutrients
Nitrate (NO3– ) concentration
(milligrams per liter)
60
40
Undisturbed
(control)
watershed
Disturbed
(experimental)
watershed
20
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
Year
Fig. 2-4, p. 37
The Second Law of
Thermodynamics in Living Systems