32 terms

# Chapter 3a - Scientific Measurements

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measurement
is a comparison of a dimension of an object or substance to an appropriate standard, usually an instrument with a calibrated scale.
standard
is a known quantity that everyone agrees will be used for comparison when measuring
instrument
any artificial device made for the purpose of refining, extending or substituting for the humans senses when measuring
dimension
a property that can be measured
calibrated scale
the spacing of the marks on the instrument
unit
the segment of a dimension assigned a value of 1 for measuring
metric system
measures meter (m) and the kilogram (kg)
measured data
has two parts:
1) a number that gives the size of the measurement
2) dimensional unit
observational bias
is a flawed perspective on data that results from a person's desire to see a certain outcome
qualitative data
described data
quantitative data
numerical data
accuracy
is an assessment of the measurement error
calibrated
..., -marked with measurements
mass
amount of matter in a given volume
objective observation
a more precised(exact) observation, more accurate-(it is not possible to be exact, but close)
subjective observation
not as precised as the projective observation
SI
Le Système International d'Unités, or the International System of Units, which is the measurement system that is accepted worldwide...METRIC SYSTEM
conversion factor
any factor (mulltiplier) used to convert from one unit of measure to another.
error
difference between a measuremnt and the actual value
accuracy
is an assessment of the measurement
precision
exactness, accuracy of a measurement
significant digit (SD)
a digit in the measurement used to communicate the precision of the measurement.
scientific notation
a convenient way to express very large or small numbers in the form of M x 10, an expression of numbers in the form m × 10n where m is equal to or greater than 1 and less than 10, and n is an integer, a way of writing very large or very small numbers using a number between 1 and 10 multiplied by a power of ten
weight (w)
force of gravity pull on the matter in an object
spring scale
an instrument that measures weight by balancing the pull of the earth's gravity on the object being weighed
electronic balance
an electronic instrument that measures the weight of an object and then displays is equivalent mass
balance
an instrument that compares a known mass to an unknown mass. when balanced the weight of the object with unknown mass equals the weight of the known mass.
volume
the space enclosed or occupied by an object
meniscus
The curved surface of a liquid
density(ρ)
the amount of mass of the substance contained in a specific volume
electronic scale
object to be weighed is placed on a metal plate on top of the instrument. the scale converts the pull of gravity on the object into an electronic signal - weight is displayed on a digital screen.
Law of mass conservation
mass is neither created or destroyed-physical or chemical change of matter is the same before after

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