BIOL 111 Chapter Notes - Chapter 3: Cosmic Ray, Electromagnetic Radiation, Universal Generalization

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3 Feb 2016
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CHAPTER 3
THE NATURE OF SCIENCE
1. A scientific hypothesis is an unconfirmed explanation of an observed phenomenon that can be tested.
2. A scientific theory is a verified, credible, and widely accepted hypothesis among scientists.
3. A scientific law is a description of what happens in nature (eg, the second law of thermodynamics).
4. Inductive (bottom-up) reasoning involves using specific observations to make a general hypothesis.
5. Deductive (top-down) reasoning involves using a generalization (logic) to make a specific hypothesis.
6. Frontier science is science that has not been widely tested and accepted.
7. Sound (consensus) science consists of data, theories, and laws that are widely-accepted.
8. Junk science consists of scientific results presented as sound science without being peer-reviewed.
MODELS AND BEHAVIOR OF SYSTEMS
1. A system is a set of components (inputs, throughputs, outputs) that function in a regular manner.
2. A feedback loop occurs when an output of information is fed back into the system as input.
3. Positive feedback (eg, new exposed land absorbs more sunlight) causes change in the same direction.
4. Negative feedback (eg, recycling aluminum) causes change in the opposite direction (reduces wastes).
5. Complex systems show a time delay between the input stimulus and response (eg, reforestation).
6. Time delays allow an environmental problem to build slowly, until a threshold level is reached.
7. Synergy is when processes interact so that the combined effect is > the sum of separate effects.
MATTER
1. Matter (eg, solid, liquid, gas, and plasma) has mass and takes up space. Stars are made of plasma.
2. An atom (element) is the smallest unit of matter that exhibits the characteristics of an element.
3. An ion (anion or cation) is an electrically charged atom or combination of atoms.
4. A molecule (compound) is combination of two or more atoms of the same or different elements.
5. Subatomic particles are positively-charged protons, negatively-charged electrons, & neutral neutrons.
6. Each element has its own atomic number, equal to the number of protons in the nucleus.
7. An element’s mass number is equal to the total number of neutrons and protons in the nucleus.
8. Various forms of an element with the same atomic number and different mass number are isotopes.
9. The amount of a substance in a unit volume in a medium (eg, air, water) is its concentration.
10. The concentration of hydrogen ions in water is represented by the pH (acidity or alkalinity).
ENERGY
1. Energy is the capacity to do work and transfer heat.
Kinetic energy is due to speed (eg, wind, flowing water, flow of electrons in a current).
Potential energy is stored energy (eg, still water behind a dam, chemical energy in gasoline).
Electromagnetic energy is carried by radiation, propagating in space as waves (eg, light).
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