Science, Systems, Matter, & Energy Chapter 2 AP Environmental Science Ms. C. Johnson Period 1

Chapter Overview Questions What are major components and behaviors of complex systems? What are the basic forms of matter, and what makes matter useful as a resource? What types of changes can matter undergo and what scientific law governs matter?

Chapter Overview Questions (cont’d) What are the major forms of energy, and what makes energy useful as a resource? What are two scientific laws governing changes of energy from one form to another? How are the scientific laws governing changes of matter and energy from one form to another related to resource use, environmental degradation and sustainability?

The Effects of Deforestation on the Loss of Water and Soil Nutrients

Science and Technology 2.1 Science – knowledge of how the world works Technology – creation of new processes intended to improve the quality of life

Scientific Method Ask a question Do experiments and collect data Formulate hypothesis to explain data Do more Experiments to test hypothesis Revise hypothesis if necessary Well-tested and accepted hypotheses become scientific theories Interpret data Well-tested and accepted patterns In data become scientific laws

Core Case Study: Environmental Lesson from Easter Island Thriving society –15,000 people by Used resources faster than could be renewed –By 1600 only a few trees remained. Civilization collapsed –By 1722 only several hundred people left. Figure 2-1

Scientists Use Reasoning, Imagination, and Creativity to Learn How Nature Works Important scientific tools –Inductive reasoning: Specific observations and measurements to arrive to a general conclusion. –Deductive reasoning: uses logic to arrive to a specific conclusion based on generalization. Scientists also use –Intuition –Imagination –Creativity

Scientific Theories and Laws Are the Most Important Results of Science Scientific theory –Widely tested –Supported by extensive evidence –Accepted by most scientists in a particular area Paradigm Shift When new information of ideas can disprove or overthrow a well-accepted scientific theory –An example is plate tectonic theory

Environmental Science Has Some Limitations Scientist can disprove things, but not prove anything absolute Bias can be minimized by scientists Environmental scientist often rely on estimates Environmental phenomena involve interacting variables and complex interactions

Matter 2.2 Nature’s Building Blocks; anything that has mass and takes up space Types of Matter: –elements – single type of atoms, cannot be broken down into other substances 92 natural +18 synthesized –compounds - 2 or more different elements, held together by chemical bonds (fixed proportions) ex: H2O

Elements Important to the Study of Environmental Science

8 elements make up 98.5% of the Earth’s crust

Compounds Important to the Study of Environmental Science

Building Blocks Atoms- smallest unit of matter –Atomic theory- all elements made up of atoms Molecules- Two or more atoms of the same or different elements held together by chemical bonds ex: H 2, O 2, N 2

Basic Chemistry Terms Atomic Number - # of protons Subatomic particles –Protons (p) with positive charge and neutrons (0) with no charge in nucleus –Negatively charged electrons (e) orbit the nucleus Mass Number- protons (+) plus neutrons(0)

Atoms, Ions, and Molecules Are the Building Blocks of Matter (2) Ions- electrically charged atom or combination of atoms –Metals- LOSE e - –Nonmetals- gain e - pH –Measure of acidity –H + and OH - –Neutral -7 –Basic 8-14 –Acid 1-6

Ions Important to the Study of Environmental Science

Loss of NO 3 − from a Deforested Watershed

Isotopes Elements with same atomic number but a different mass # (C 12, C 13 & C 14 )

Atoms, Ions, and Molecules Are the Building Blocks of Matter (3) Chemical formula – type of short hand to show the type and # of atoms/ions in a compound. Ex. NaCl or CH 4 Ionic compound- made up of opposite charged ions Na + Cl - Covalent compounds- uncharged atoms CH 4

Organic Compounds Contain carbon and hydrogen –Hydrocarbons C 8 H 18 gasoline and chlorinated hydrocarbons C 14 H 9 Cl 5 DDT –Simple carbohydrates C 6 H 12 O 6 –Macromolecules: complex organic molecules Complex carbohydrates Proteins Nucleic acids Lipids

Inorganic Compounds No carbon to carbon or carbon to hydrogen bonding, not originating from a living source –Earth’s crust – minerals,water –Water, nitrous oxide, nitric oxide, carbon monoxide, carbon dioxide, sodium chloride, ammonia

Matter Comes to Life through Genes, Chromosomes, and Cells Cells: fundamental units of life Genes: sequences of nucleotides within the DNA Chromosome: composed of many genes

Matter Occurs in Various Physical Forms Solid Liquid Gas High-quality matter Low-quality matter

Matter Quality: High or Low A measure of how useful matter is for humans based on availability and concentration.

Matter Undergoes Physical, Chemical, and Nuclear Changes Physical change - chemical composition not changed ex: water and ice Chemical change or chemical reaction- chemical composition has changed Nuclear change –Natural radioactive decay Radioisotopes: unstable –Nuclear fission (split apart) –Nuclear fusion (fuse together)

Nuclear Changes Nuclei of certain isotopes spontaneously change (radioisotopes) or made to change into one or more different isotopes –Alpha particles –Beta particles –Gamma rays –Neutrons –Positrons

Fig. 2-7, p. 41 Stepped Art Beta particle (electron) Radioactive decay Radioactive isotope Alpha particle (helium-4 nucleus) Gamma rays Nuclear fission Uranium-235 Energy Fission fragment Fission fragment Neutron n Uranium-235 n n n n n Nuclear fusion Fuel ProtonNeutron Hydrogen-2 (deuterium nucleus) Hydrogen-3 (tritium nucleus) Reaction conditions 100 million °C Products Helium-4 nucleus Energy Neutron

Ionizing and Nonionizing Radiation Ionizing: radiation with enough energy to change the structure of molecules or atoms –Gamma, ultraviolet Nonionizing: radiation that does not change the structure of molecules or atoms –Alpha, infrared

Half - Life Time needed for one-half of the nuclei in a radioisotope to decay and emit their radiation. General rule for decay: goes through 10 half –lives before it becomes a non- radioactive form.

We Cannot Create or Destroy Matter Law of conservation of matter –no atoms are created/destroyed during a physical or chemical change. Matter consumption –Matter is converted from one form to another

Energy quality 2.4 Measure of how useful an energy source is in terms of concentration and ability to perform useful work

Severity of Pollutants Chemical Nature Concentration: ppm Persistence: categories –Degradable/Biodegradable: human sewage, leaves –Persistent -decades-plastics and DDT –Nondegradable-lead, arsenic, mercury

Energy E= capacity to do work (w =f x d) Types: –Kinetic Energy -energy in motion –Potential energy - stored energy Forms of energy: –Light, heat, electrical, chemical, electromagnetic radiation

Electromagnetic radiation * energy that travels in waves * shorter wave lengths = high energy

X-ray image of SunRadio image of sun UV image of Sun Light image of Sun

Fig. 2-8, p. 42 Ultraviolet Energy emitted from sun (kcal/cm 2 /min) Visible Wavelength (micrometers) Infrared

US Frequency Allocations

First Law of Thermodynamics Also known as law of conservation of energy Energy can change from one form to another but can never be destroyed No “away” in “throw away” -things that have been thrown away are still present on Earth, but just exist in another form.

Second Law of Thermodynamics You cannot even break even –When energy is changed from one form to another, some of the useful energy is always degraded to lower quality, more dispersed, less useful energy.

The Second Law of Thermodynamics in Living Systems

Systems 2.5 –Systems: set of components that function and interact in some way. Key Components: –Inputs from the environment (energy, matter, information) –Throughputs: flow of input within the system –Outputs to the environment (energy, matter, information) Models can used to test these systems. – Ex: Mathematical Models – use of equations

Feedback Loop and Systems Change in one part of a system influences another part of the system

Positive Feedback Loop –Causes system to change in same direction. Example: Exponential growth of population – more individuals lead to increased number of births

Negative Feedback Loop –Causes system to change in opposite direction. Example: Temperature regulation in humans – increased temperature leads to decrease in temperature by sweating

What Affects Complex Systems? Time lags/ time delays – change in a system leads to other changes after a delay (input response) –Problems can build slowly in systems until reaching a tipping point –Ex: lung cancer Resistance to change – built in resistance – political or economic Synergy-when two or more processes interact so that the combined effect is greater Chaos – unpredictable behavior in a system

Implications for the Environment – High Waste Society

Implications for the Environment – Low Waste Society