UNIT # 2 Environmental Science Matter and Energy
UNIT # 2 Environmental Science – Matter and Energy
A ) CASE STUDY – Easter Island
Easter Island or Rapa Nui
Basic Information:
- Relatively large Island – 163.6 km2 - 64 square miles
Stillwater – 28.4 square miles
Sandyston – 43.3 SM
- Located in a subtropical region 270 S. Latitude (mild climate)
- 3600 km – 2000 miles West of Chile
- rich Volcanic soils
Inhabitation:
- 2 Estimates
- ~ 800 A.D. – radiocarbon dating / linguistic studies
- ~ 1200 A.D. – updated radiocarbon dating
- Population estimated 6000 – 20,000 – some as low as 3,000
Stillwater ~ 4300
Sandyston ~ 1900
- Polynesians
Life on the island before inhabitation:
- Pollen studies show rich subtropical forest on island for 35,00 years before
inhabitation
- Large palm in family Jubaea
- Large basswood trees
- Numerous land and pelagic birds
Frigate birds, Albatross, terns
Life during early inhabitation:
- Early fire pits showed remains of – Fish >1/4 , porpoise ~ 1/3, birds – frigate birds, albatross, boobies, terns at east 25 species
- Also showed rats (possibly imported as food) Chickens
- Around 1280 deforestation begins to occur
* Used for fuel
* Used for canoes
* Used to move famous Easter Island Statues – Moai
* possibly deforested by imported rats
- Deforestation led to some erosion
- ½ native species became extinct
- 1722 Dutch explorer Jacob Roggeveen found
* Island of grasses little to no trees
* 2-3 thousand malnourished natives
- Some evidence of cannibalism
WHAT CAN BE LEARNED?
B) Matter and the hierarchy of the Earth
Matter- anything that has volume and mass
- All life is made up of matter
- Matter must be looked at as finite
- Matter is cycled through biogeochemical cycles of the Earth
* High Quality Matter – highly concentrated (refined, pure )
- easily gathered
- easily concentrated and purified for use
- Fuel, aluminum cans, coal, salt
ALUMINUM RECYCLING
Recycling requires less than 5 percent
one can, can save enough energy to keep a 100-watt bulb burning about three and a half hours.
one-tenth the cost of the facilities to mine and refine ore
* Low quality Matter – dilute / dispersed matter
- tough to concentrate
- requires quite a bit of energy to make useful
- Bauxite ore, exhaust gas, salt solution
Atoms – Smallest unit of matter which holds the chemical properties of the atom
Biologically important – C,H,O,N,P,S, Ca, K, Na, Cl, Mg - 99%
All other 81 natural
* Isotopes – atoms with unequal # of protons to neutrons
Examples – H1 1P 0N – hydrogen
H2 1P 1N – deuterium
H3 1P 2N – tritium
Molecule- two or more atoms bonded together in a specific ratio
Organic – Molecule made up of carbon rings or chains by living things
Inorganic – all other molecules
Organelle –
Cell –
Tissue –
Organ –
Organ System –
Organism –
Populations – a group of like organisms living in a given region
Communities – all of the populations in a given area
Ecosystem – The organisms of a region as well as the abiotic environment
Biosphere – anywhere on Earth which life can be found
III. Pollution and the law of conservation of mass
· Matter cannot be created nor destroyed
What does this mean for pollutants?
Pollutants must be dealt with. What we need to analyze.
- Toxicity
- Concentration of pollution
- Persistence of pollution
How can we deal with pollution.
1- Matter must either stay as a pollutant
2- Be collected and recycled
3- Be collected and interned
4- Degrade naturally
· Degradable
broken down through biological means
chemical means
radioactive
physical means
· Slowly degradable (persistent pollution)
DDT
Plastics
Nuclear waste
· Non-degradable
Elements Pb Hg As
IV. Special consideration Nuclear waste
Radioactive material – Atoms which have unstable nuclei which degrade releasing matter (alpha and beta particles) and radiant energy gamma rays.
Half life – the time required for ½ of the material to change into another isotope.
· Steady
· Cannot be changed
· Often 10 half lives is thought about as bringing material to safe level
C14 - 4730 +/- 40 yr
I 131 – 8.0197 days
Pu 239 – 24110 Yrs
Danger – Radioactive materials are mutagenic carcinogenic and teratogenic
Energy and particles disrupt DNA
Where do these toxins come from?
· Fission – The splitting of large nuclei of isotopes
- Produces smaller elements / isotopes
- Produces energy
- Produces neutrons
+ Neutrons cause other fission reactions – chain reaction
+ Controlled Nuclear reactor
+ Uncontrolled nuclear bomb - atomic bombs – A bombs
August 6th 1945 – Uranium based bomb – Hiroshima
August 9th 1945 – Plutonium Based bomb – Nagasaki
100,000-200,000 deaths
· Fusion – The building of a larger nucleus from two smaller nuclei
+ High pressures and temperatures
+ H2 – Deuterium + H3 Tritium à He4 + neutrons + energy
1P/1N + 1P/2N à 2P/2N + N
+ Hydrogen Bomb – H bomb – thermonuclear bomb
These are a thousand times more powerful than H bombs
V. Energy and the environment
Energy- The ability to do work or cause motion
2 Types
Kinetic energy – The energy of movement
- Mechanical
Wind
Water
- Heat
- Electromagnetic spectrum
Cosmic rays à radio waves
High energy Low energy
- Electrical – movement of electrons
Potential energy – Stored energy
- Stored due to position – rock, hydroelectric
- Chemical energy – stored in the bonds of molecules
- Nuclear energy – energy stored in the nucleus of atoms
Laws governing the use of energy
1st law of thermodynamics – energy cannot be created nor destroyed
Energy in = energy out
Finite energy on Earth
Energy can be transformed but not created
2nd law of thermodynamics – in any energy conversion some energy
will be “lost” as low grade energy
Energy going through transformations is degraded in process
Degradation is called Entropy
Entropy usually results in heat
Examples:
Fuel oil – oil (chemical potential energy) burned to release
heat for heating your home
Heat = low quality kinetic energy
- cannot be harnessed and reused
- escapes into atmosphere
Gasoline – High quality CPE burned
Some energy as movement of vehicle
Some as chemical potential energy (battery)
Some as light
Most as heat
Photoautotrophs – Solar energy (kinetic energy)
Converted to chemical potential energy
Some lost as heat during chemical reactions
Trophic levels – food chains
Rule of 10%
Most lost as heat – organism movement
Homeotherms
Chemical reactions
VI. What does the law of conservation of matter and the laws of
thermodynamics mean to mankind?
Focus must be on reducing matter and energy use.
5 “R’s”
* Refuse – do not purchase materials that are high pollution causers
* Replace – Find alternate sources for materials
* Reduce – Attempt to find ways to reduce initial
* Reuse – Use products for full life / find alternate uses for them
* Recycle – Reforming materials
Increase efficiencies
* Look to maximize amount of energy obtained from high quality
Energy
* Look to maximize matter resource – reduce waste
Move towards Low- throughput society
- Increase efficiencies of resource use
- Put in place matter feedback loops
- Look to reduce overall use of all products