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20 Cards in this Set
 Front
 Back
System

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 

Scientific Method

logical approach to solving problems by observing and collecting data, formulating hypotheses, testing hypotheses, and formulating theories that are supported by data


Hypothesis

testable statement


Model

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 

Theory

a broad generalization that explains a body of facts or phenomena


Quantity

something that has magnitude, size, or amount
not the same as measurement; quantity represented by a teaspoon is volume 

SI

scientists all over the world have agreed on a single measurement system called Le Systeme International de Unites


Weight

a measure of the gravitational pull on matter


Derived units

combinations of SI base units


Volume

the amount of space occupied by an object


Density

the ratio of mass to volume
MASS DIVIDED BY VOLUME D=M/V 

Conversion factor

a ration derived from the equality between two different units that can be used to convert from one unit to the other


Dimensional analysis

mathematical technique that allows you to use units to solve problems involving measurements


Accuracy

refers to the closeness of measurements to the correct or accepted value of the quantity measured


Precision

refers to the closeness of a set of measurements of the same quantity made in the same way


Percentage error

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 

Significant figures

in a measurement consist of all the digits known with certainty plus one final digit, which is somewhat uncertain or is estimated


Scientific notation

numbers are written in the form M x 10^nwhere 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 

Directly proportional

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 

Inversely proportional

two quantities are  to each other if their product is constant
