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20 Cards in this Set
- Front
- Back
System
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specific portion of matter in a given region of space that has been selected for study during an experiment or observation
--when you observe a reaction in a test tube, the test tube and its contents form a system |
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Scientific Method
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logical approach to solving problems by observing and collecting data, formulating hypotheses, testing hypotheses, and formulating theories that are supported by data
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Hypothesis
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testable statement
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Model
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in science is more than a physical object; it is often an explanation of how phenomena occur and how data or events are related
--may be visual, verbal, or mathematical |
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Theory
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a broad generalization that explains a body of facts or phenomena
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Quantity
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something that has magnitude, size, or amount
--not the same as measurement; quantity represented by a teaspoon is volume |
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SI
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scientists all over the world have agreed on a single measurement system called Le Systeme International de Unites
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Weight
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a measure of the gravitational pull on matter
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Derived units
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combinations of SI base units
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Volume
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the amount of space occupied by an object
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Density
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the ratio of mass to volume
MASS DIVIDED BY VOLUME D=M/V |
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Conversion factor
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a ration derived from the equality between two different units that can be used to convert from one unit to the other
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Dimensional analysis
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mathematical technique that allows you to use units to solve problems involving measurements
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Accuracy
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refers to the closeness of measurements to the correct or accepted value of the quantity measured
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Precision
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refers to the closeness of a set of measurements of the same quantity made in the same way
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Percentage error
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is calculated by subtracting the accepted value form the experimental value, dividing the difference by the accepted value, and then multiplying by 100
PE = Ve - Va / Va X 100 |
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Significant figures
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in a measurement consist of all the digits known with certainty plus one final digit, which is somewhat uncertain or is estimated
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Scientific notation
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numbers are written in the form M x 10^n--where the factor M is a number greater than or qual to 1 but less than 10 and is a whole number
65000 = 6.5 x 10^4 |
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Directly proportional
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to each other if dividing one by the other gives a constant value
--if the masses and volumes of diff. samples of aluminum are measure, the masses and vulumes will be directly proportional to each other |
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Inversely proportional
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two quantities are ----- to each other if their product is constant
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