ch. 2 - measurements & calculations Flashcards
observation
using 5 senses to obtain info
research
reliable sources to learn background info
hypothesis
a testable statement that serves as a basis for predictions and further experimenting
(if… then… because); a proposal
experiment
testing hypothesis in order to provide data that supports or refutes it
qualitative data
descriptive (ex; texture, color)
quantitative data
numbers (ex; graphs, counting, measuring)
variables
experimental conditions that change or can be changed
independent variable
is changed by experimenter, affects dependent dependent
dependent variable
being tested and measured, affected by independent
control
experimental conditions that stay constant/continuous; a comparison to another thing
theory
BROAD GENERALIZATION used to explain observations; lots of evidence to support it but can change overtime
model
PHYSICAL OBJECT that explains/illustrates complex concepts OR an explanation of how phenomena occur and how data/events are related
weight vs mass
weight = measure of gravitational pull on matter mass = measure of the quantity of matter; DOES NOT depend on gravity
precision vs accuracy
precision = same results repeatedly accuracy = matches up to actual data
inversely vs directly proportionate
inversely = while one variable decreases, the other increases (product has a constant value) directly = if one variable increases/decreases, the other does too (dividing one by the other gives a constant value)
scientific notation (rules)
m(10^n) - m is greater than or equal to 1 but less than 10; n is a whole number
addition & subtraction = VALUES HAVE TO HAVE SAME EXPONENTS! – stay the same when # is added
multiplication = exponents are added
division = exponents are subtracted
scientific method
a logical approach to solving problems by observing and collecting data, formulating hypotheses, testing hypotheses, and formulating theories supported by data
what are SI measurements and what are the 7 base units?
a system that scientists worldwide agreed on
7 base units = meters (length), kilograms (mass), seconds (time), kelvin (temperature), mole (amount of substance), amperes (electric current), candela (luminous intensity)
derived SI units
square meter (area), cubic meter (volume)
density
ratio of mass to volume
conversion factors
used to convert from one unit to another
quantity giver x conversion factor = quantity sought
percentage error
experimental value minus accepted value divided by accepted value and multiplied by 100
significant figures
consist of all the digits known with certainty plus one final digit, which is somewhat uncertain or estimated
addition/subtraction = answer has no more digits to the right of the decimal point than there are in # w/ smallest number of sigfigs to the right of decimal point
multiplication/division = answer has no more sigfigs than the # with the fewest sigfigs
exact conversion factors
completely certain and don’t limit # of digits in calculation
system
specific matter in a given region of space that has been selected for study during an experiment or observation.
derived units
a combination of SI base units
system
specific portion of matter in a given region of space that has been selected for study during an experiment or observation
