23 terms

# Unit 1 Vocabulary

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Scientific Method
A logical, systematic approach to the solution of scientific problems
Hypothesis
A proposed explanation for an observation.
Experiment
A procedure that is used to test a hypothesis
Independent Variable
The variable that the experimenter changes during an experiment. It is also called the manipulating variable.
Dependent Variable
The variable that is observed during the experiment. It is also called the responding variable.
Theory
A well-tested explanation for a broad set of observations. It can never be proven because it is possible that it may be changed in the future.
Law
A concise statement that describes an observation and is well-tested.
Chemical Change
A change that produces matter with a different composition than the original matter
Chemical Property
A description of the ability of a substance to undergo a specific chemical change.
Physical Change
A change during which some properties of a material change, but the composition of the material does not change
Physical Property
A description of a quality or condition of a substance that can be observed or measured without changing the composition of the material
Extensive Property
A property that depends on the amount of matter in a sample
Intensive Property
A property that depends on the type of matter in a sample, not the amount of matter
Precipitate
A solid that forms and settles out of a liquid mixture
Accuracy
The closeness of a measurement to the true or accepted value of what is being measured
Precision
Describes the closeness of a set of measurements taken under the same conditions.
International System of Units
The revised version of the metric system adopted by international agreement in 1960
Measurement
A quantitative description that includes both a number and unit
Percent error
The percent that a measure value differs from the accepted value
Significant Figures
All the digits that can be known precisely or with certainty in a measurement plus a last estimated digit.
Kelvin
The temperature scale in which the lowest temperature is absolute zero
Dimensional Analysis (Factor-label)
A technique of problem solving that uses units that are part of a measurement to help solve the problem
Conversion Factor
a ratio of equivalent measurements used to convert a quantity from one unit to another