Paper 6 practical test Flashcards
define true value
value you get in an ideal experiment
define measurement error
diff btw measured value and true value
define accuracy
how close measurement is to true value
define precision
-how close the reading are to each other
-how detailed the values are
define reliability
variations btw values is small; produce consistent result
eg. repeat experiment multiple times
define repeatability
if you can get same result when doing the same experiment again
define reproducibility
if you can get same results when doing a diff experiment
define validity
experiment is fair or not
have controlled variables
define range
max and minimum values of the variables
define anomaly
value which is outside of general pattern of values
define dependent variables
-what you measure
-x axis
-left of table
define independent variable
-what you change
-y axis
-right of table
define control variables
-what you keep the same
-helps with comparison
-for validity
how to increase reliability
-take minimum 3 readings and find mean
-repeat experiment and find mean value
-make sure rest of variables are controlled
how to increase accuracy
-use proper apparatus
-use correct method when using apparatus
-repeat readings
-take readings at smaller intervals and find mean
how to increase precision
-like more decimal place (eg. 3.2 is more precise than 3)
-use proper apparatus (more suitable ones)
-raw value is more precise than mean value
what is amount used for
-time
-energy
-money
what word do you use for liquid
-volume
-ml
-cm^3
what word do you use for countable things
number
what word do you use for like measuring solute is solvent (eg. salt in water)
-concentration
-mol/ dm^3
-%
what word do you use for measure mass
-mass
-kg
-g
percentage change formula
final - initial
——————- X 100%
initial
rules for drawing graphs
-independent variable - x axis
-dependent variable - y axis
-x & y axis must be labeled with units
-draw the line of best fit- curve or straight
-scale must be even on both side
-use up more than half of the paper on both sides ( x & y)
-plot using “x” - has to be in middle of 4 boxes
-graph doesn’t have to start from 0
how do you calculate gradient
-rise over run (hypothenuse)
-in 3 sf
why is repeating and finding mean/ average reliable
identifies anomalies
note: same decimal place in table & units in heading
why does a reaction stop
-the reactants are used up
define validity
how appropriate an experimental method is to achieve the aim of the experiment
why must you let the plant sit for 10 min before taking measurements
to give the plant time to adjust to the conditions & equilibrate
Requirements when planning an experiment
DR SICA
D - dependent variable; how to measure; unit & precision of measurement
R - repeats & find mean
S - safety; hazards; how to reduce risks
I - independent variable; method; range
C - control variables; how to control each
A - apparatus used
