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Unformatted text preview: Science, Systems, Matter, and Energy CHAPTER 2 PART 1 Key Concepts: What is Science? Matter Laws of matter Energy Laws of energy Scientific Thinking Science is an attempt to understand nature and use that knowledge to make predictions . When scientists think they know what is going on or why this or that works the way it does, they postulate a hypothesis , an explanation of what they have observed. To be valid, these hypothesis must adequately explain all cases relating to the subject. Scientific Theories If it passes all these tests, a hypothesis becomes a scientific theory. Theories are well documented and tested explanations of observed phenomena. To scientists, a theory is as close to reality as you will ever come. The 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 hypothesis become scientific theories Scientific Theory vs Layman Theory Scientific theories are serious explanations of natural phenomena. They are not just a casual idea of what is happening. Until someone presents rigorously tested evidence to counter the current theory, the theory holds. The scientific process always leads to more questions and ideas The bottom line: Scientists can do two things: (1) prove that something is wrong (2) establish that a model, theory or law has a very high probability of being true (statistics) The term scientifically proven is a misnomer, (ie misleading). Most scientists dont use the word proof, at least not in scientific journals Word of caution about predictions: it is better to use the term likely to happen, or will happen to the best of our knowledge Other Science Types Frontier Science preliminary results, can be argued about, put out so that others can get involved in the controversy Sound science (consensus science) generally agreed upon, widely accepted in peer reviewed journals Junk science presented as sound science but has not undergone peer review, ie not widely accepted How to ferret out junk science: Are they experts, source of funding, compare with consensus, impartial peer review? Matter: Forms, Structure, and Quality Elements Compounds Atoms Ions Molecules Matter : Anything that takes up space, elements and compounds Atoms : Subatomic Particles: protons, neutrons, electrons Atomic characteristics: Atomic number, atomic mass, ions, isotopes Electrons vs Protons Electrons are negative charged particles and have very little mass compared to protons Protons (+ charge) are found in the nucleus Neutrons no charge, found in the nucleus Atomic # and Mass # Atomic # = number of protons (and number of e- as they are equal) The mass number is the number of protons and neutrons in the nucleus Ion vs Isotope Ions are electrically charged atoms, this occurs when an atom loses or gains an electron ie, Salt in water: Na+ & Cl- ions in solution...
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- Spring '09