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19 Cards in this Set
- Front
- Back
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Isotopes
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Atoms of the same element with different numbers of neutrons.
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Radioactive Decay
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The spontaneous release of material from the nucleus of radioactive isotopes.
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Half-Life
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The time it takes for one-half of an original radioactive parent atom to decay. It is a useful parameter to know because some elements that undergo radioactive decay emit harmful radiation. Knowledge of the half-life allows scientist to determine the length of time that a particular radioactive element may be dangerous. |
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pH
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The number that indicates the relative strength of acids and bases in a substance. A pH value of 7 is neutral (pure water). Anything over 7 is basic, or alkaline, (seawater, bleach, sodium hydroxide). Anything under 7 is acidic (rainwater, cola beverage, stomach fluid). The lower the number, the stronger the acid, and the higher the number, the more basic the substance.
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Law of Conservation of Matter
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A law of nature stating that matter cannot be created or destroyed; it can only change form.
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Potential Energy
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Stored energy that has not been released.
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Kinetic Energy
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The energy of motion.
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Chemical Energy
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Potential energy stored in chemical bonds.
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1st Law of Thermodynamics
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A physical law which states that energy can neither be created nor destroyed but can change from one form to another. This law dictates that you can't get something from nothing. When an organism needs biologically usable energy, it must convert it from an energy source such as the Sun or food. The potential energy contained in firewood never goes away but is transformed into heat permeating a room when the wood id burned in a fireplace.
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2nd Law of Thermodynamics
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The physical law stating that when energy is transformed, the quantity of energy remains the same, but its ability to do work diminishes. To understand this law, we use the concept of energy efficiency. An example of this is how a car changes energy into a less usable form, heat. The heat that is created is called waste heat, meaning that it is not used to do any useful work. And it is inevitable that any time there is a conversion of energy from one form to another, some of that energy will be lost as heat.
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Energy Efficiency
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The ratio of the amount of energy expended in the form you want to the total amount of energy that is introduced into the system. We can also calculate the energy efficiency of transforming one form of energy to another into other forms of energy. The energy efficiency of a traditional fireplace is low because so much heated air can escape through the chimney. Whereas a modern woodstove, which can heat a room using much less wood, is considerably more energy efficient.
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Energy Quality
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The ease with which an energy source can be used for work.
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Open System
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A system in which exchanges of matter or energy occur across system boundaries.
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Closed System
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A system in which matter and energy exchanges do not occur across boundaries.
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System Analysis
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An analysis to determine inputs, outputs, and changes in a system under various conditions.
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Steady State
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A state in which inputs equal outputs, so that the system is not changing over time.
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Negative Feedback Loops
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A feedback loop in which a system responds to a change by returning to its original state, or by decreasing the rate at which the change is occurring. Happens in natural systems. An example is, when water levels drop, there is less lake surface area, so evaporation decreases. With less evaporation, the water in the lake slowly returns to its original volume. (Resists Change) |
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Positive Feedback Loops
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A feedback loop in which changes in a system is amplified. Also occurs in the natural world. The more members of a species that can reproduce, the more births there will be, creating even more of the species to give birth, and so on. (Amplifies Change) |
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Adaptive Management
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A plan that provides flexibility so that managers can modify it as changes occur. A plan for addressing future problems. It is the answer to scientific uncertainty. In a highly complex system, any changes, however well intentional, may have unexpected consequences.
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