scientic method
logical approach to sloving problems by observing and colecting data, formulating hypothesis, testing hypotheses,formulating theories that are supported by data.
observing
use of the senses to obtain information
qualitative
describes
quantitative
numerical
system
specific portion of matter in a given region of space that has been selected for study during an experiment or observation.
hypothesis
testable statment
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. can be- visual,verbal,mathematical.
a theory
is a broad generalization that explains a body of facts or phenomena.
why is it important for a measurement system to have an international standard?
to have universal agreement and avoid confusion.
measurements
quantitative information.represent quantities.
quantity
something that has magnitude,size, or amount.
SI units
measurment system, terms of standards of measurement.
unit
compare what is to be measured with a previously defined size.
seven SI units and there quantity
1.meter-length;2.kilograms-mass;3.second-time;4.kelvin-temperature;5. mole-amount of substance
6. ampere-electric current 7.candela-luminous intensity
kilo
1000
hecto
100
deka
10
deci
1/10
centi
1/100
mili
1/1000
micro
1/1000 000
mass
measure of the quantity of matter. standard unit-kilograms.--balance
weight
a measure of the gravitational pull on matter;
spring scale
meter
standard unit for length.
explain why the second is not defined by the length of the day?
fundamental units must be unvarying,but day length depends on earth's rotation rate, which is not constant.
derived unit
combinations of SI base units. produced by muiltplying or dividing standard units.
volume
amount of space occupied by an object
area
square meters-length*width
derived SI unit for volume
cubic meter--length
width
height
derived SI unit for density
kilograms per cubic meter---mass/volume
density
the ratio of mass to volume or mass divided by volume
conversion factor
ratio deribed from teh equality between two different units that can be used to convert from one uint to the other.
accuracy
refers to the closeness of measurements to the correct or accepted value
precision
refers to the closeness of a set of measurements to one another
percent error
calculated by subtracting the experimental value from the accepted value, dividing the differences by the accepted value, and then multiplying by 1oo.
under what condition will percent error be negative?
if the accepted value is less than the experimental value.
how is the average for a set of values calculated?
by adding the values and dividing by the number of values.
state the rules governing the number of significant figures if addition and subtraction.
answer must have the same # of digits to the right of the decimal point as there are in the measurement with the fewest digits to the right of the decimal point.
state the rules governing the number of significant figures if multiplication and division
answer can have no more significant figures than are in the measurement with the fewest number of significant figures.
analyze
first step. read the problem carefully at least twice and to analyze the infor in it.
plan
second step. develop a plan for solving the problem
compute
third step.subsitute data&neccessary conversion factors into the plan you have developed.
evalute
fourth step. examine your answer to determine whether it is reasonable.
directly proportional
to each other if dividing one by the other gives a constant value. y/x=k or y=kx
inversely proportional
to each other if their product is constant. xy=k
scientic method
logical approach to sloving problems by observing and colecting data, formulating hypothesis, testing hypotheses,formulating theories that are supported by data.
observing
use of the senses to obtain information
qualitative
describes
quantitative
numerical
system
specific portion of matter in a given region of space that has been selected for study during an experiment or observation.
hypothesis
testable statment
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. can be- visual,verbal,mathematical.
a theory
is a broad generalization that explains a body of facts or phenomena.
why is it important for a measurement system to have an international standard?
to have universal agreement and avoid confusion.
measurements
quantitative information.represent quantities.
quantity
something that has magnitude,size, or amount.
SI units
measurment system, terms of standards of measurement.
unit
compare what is to be measured with a previously defined size.
seven SI units and there quantity
1.meter-length;2.kilograms-mass;3.second-time;4.kelvin-temperature;5. mole-amount of substance
6. ampere-electric current 7.candela-luminous intensity
kilo
1000
hecto
100
deka
10
deci
1/10
centi
1/100
mili
1/1000
micro
1/1000 000
mass
measure of the quantity of matter. standard unit-kilograms.--balance
weight
a measure of the gravitational pull on matter;
spring scale
meter
standard unit for length.
explain why the second is not defined by the length of the day?
fundamental units must be unvarying,but day length depends on earth's rotation rate, which is not constant.
derived unit
combinations of SI base units. produced by muiltplying or dividing standard units.
volume
amount of space occupied by an object
area
square meters-length*width
derived SI unit for volume
cubic meter--length
width
height
derived SI unit for density
kilograms per cubic meter---mass/volume
density
the ratio of mass to volume or mass divided by volume
conversion factor
ratio deribed from teh equality between two different units that can be used to convert from one uint to the other.
accuracy
refers to the closeness of measurements to the correct or accepted value
precision
refers to the closeness of a set of measurements to one another
percent error
calculated by subtracting the experimental value from the accepted value, dividing the differences by the accepted value, and then multiplying by 1oo.
under what condition will percent error be negative?
if the accepted value is less than the experimental value.
how is the average for a set of values calculated?
by adding the values and dividing by the number of values.
state the rules governing the number of significant figures if addition and subtraction.
answer must have the same # of digits to the right of the decimal point as there are in the measurement with the fewest digits to the right of the decimal point.
state the rules governing the number of significant figures if multiplication and division
answer can have no more significant figures than are in the measurement with the fewest number of significant figures.
analyze
first step. read the problem carefully at least twice and to analyze the infor in it.
plan
second step. develop a plan for solving the problem
compute
third step.subsitute data&neccessary conversion factors into the plan you have developed.
evalute
fourth step. examine your answer to determine whether it is reasonable.
directly proportional
to each other if dividing one by the other gives a constant value. y/x=k or y=kx
inversely proportional
to each other if their product is constant. xy=k