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| Attempt to discover order in the natural world and to use that knowledge to make predictions about what is likely to happen in nature | ||
| Widely tested and accepted hypothesis | ||
| What we find happening over and over again in nature | ||
| (1) publish details of methods, results of experiments and models, reasoning behind hypotheses; (2) other scientists in same field examine and criticize | ||
| The changing parts of the experiment | ||
| Isolate and study one variable at a time | ||
| chosen variable is changed in a known way | ||
| no treatment group | ||
| parts of experiment that Stay the Same | ||
| specific observations and measurements arrive at a general conclusion or hypothesis bottom-up reasoning going from specific to general | ||
| logic to arrive at a specific conclusion top-down approach that goes from general to specific | ||
| has not been widely tested (starting point of peer-review) | ||
| consists of data, theories and laws that are widely accepted by experts | ||
| is presented as sound science without going through the rigors of peer-review | ||
| System changes further in the same direction Example: loss of ice caps and global warming | ||
| System changes in opposite direction; corrective Example: aluminum recycling results in less aluminum ore needing to be mined from earth's crust | ||
| Occurs when two or more processes interact so that the combined effect is greater than the sum of their separate effects Example: smoking cigarettes and asbestos exposure: fifty times more likely to develop lung cancer | ||
| anything that has mass and takes up space; ex: solids, liquids, gases | ||
| building blocks of matter | ||
| 2 or more different elements held together | ||
| smallest unit of matter that exhibits characteristics of a specific element | ||
| found in nucleus of atom - positive charge | ||
| found in nucleus of atom - no charge | ||
| "floating" around nucleus of atom - negative charge | ||
| center of an atom made of protons and neutrons | ||
| number of protons in an atom | ||
| number of protons and neutrons in an atom | ||
| element with same atomic number (same protons) and different atomic mass due to different number of neutrons | ||
| atom or groups of atoms with net positive or net negative charge | ||
| acidity of a solution; hydrogen ion concentration in 1 liter of water; "potential of hydrogen" | ||
| pH of 7; ex: water | ||
| pH less than 7 and possibly as low as 0; ex: lemon juice, vinegar | ||
| pH more than 7 and possibly as high as 14; ex: soaps, detergents, baking soda | ||
| Two or more atoms of the same or different elements Building blocks of compounds Examples: C6H12O6 O2 | ||
| shorthand ways to show the atoms and ions in a chemical compound. | ||
| has carbon and hydrogen; ex: macromolecules, biomass | ||
| may have carbon or hydrogen or neither; ex: water, minerals, salt, iron | ||
| basic structural and functional units of all forms of life | ||
| organic and necessary for life; ex: carbohydrates, lipids, proteins, nucleic acids | ||
| segment of DNA that codes for a trait | ||
| all the DNA of a cell condensed and found in the nucleus of eukaryotic cells; ex: humans have 46 of them in their body cells and only 23 of them in their sex cells | ||
| is concentrated and easily extracted; ex: coal, gasoline | ||
| is more widely dispersed and more difficult to extract; ex: exhaust from automobile, air pollution and emissions from a power plant | ||
| maintains original chemical composition; ex: breaking a piece of ice into smaller pieces of ice | ||
| chemical reaction which changes the arrangement of the elements or compounds involved; coal is burned and released into the air as sulfur dioxide and carbon dioxide | ||
| When a physical or chemical change occurs, no atoms are created or destroyed | ||
| measure of how long it stays in the air, water, soil, or body | ||
| broken down completely or reduced to acceptable levels | ||
| living organisms (usually bacteria) break down matter | ||
| takes decades or longer to degrade; ex: DDT | ||
| cannot be broken down; ex: lead, mercury, arsenic | ||
| unstable isotopes (radioactive isotopes or radioisotopes) spontaneously decay at a constant rate and give off energy | ||
| unstable isotopes that result from natural radioactive decay | ||
| time needed for one-half of the nuclei to decay to form a different isotope | ||
| splitting of atoms; ex: process used at nuclear power plant | ||
| atoms being joined together; ex: process used on sun | ||
| energy in motion | ||
| energy at rest | ||
| flows from hotter object to cooler object | ||
| concentrated; can perform much useful work | ||
| dispersed and has little ability to do useful work | ||
| also 1st law of thermodynamics; energy is not created or destroyed, just changes forms | ||
| energy quality always decreases; entropy increases |
