Practical skills Flashcards
what are the 6 base SI units
length (meter/m)
time (seconds/s)
mass (kilogram/km)
Temperature (kelvin/K)
electrical current (amp/A)
amount of substance (mole/mol)
what are the 10 prefixes
Tera T (10^12)
Giga G (10^9)
Mega M (10^6)
kilo k (10^3)
centi c (10^-2)
milli m (10^-3)
micro mew (10^-6)
nano n (10^-9)
pico p (10^-12)
femto f (10^-15)
what are the 3 variables
IV- thing you are changing
DV- thing you are measuring
CV- thing you are keeping the same
what is a hazard
thing that can cause harm
what is a risk
how someone could be harmed
what is a prevention
how someone can be prevented from harm
when would you use a micrometer
when there’s a very small distance
eg. diameter of a wire
how do you use a micrometer
place an object between the jaws (anvil and spindle) and turn the ratchet to tighten (ratchet prevents object from getting squashed)
when would you use a vernier calliper
when measuring an object or an internal diameter.
however there is no ratchet
what are the differences with different vernier scales
a vernier scale is essentially a zoomed in version of 1mm. depending on how many divisions it has is it precision. eg. 10 divisions means a precision of 0.1mm
what are the 4 types of data
discrete-only set numbers
continuous-any value
categoric-has categories (doesn’t need to be numerical)
ordinal- can be put in order (ranked)
what are the rules when making tables
independent variable on the left
7 readings taken
all measurements taken to the same precision (which is of the equipment)
units written in heading
averages ignore anomalies
how many decimal places should data be written to
raw data- precision of the equipment
calculated- same number across column
what are the 2 types of error
systematic-all readings off by the same amount (calibrate equipment)
random- readings off by different amounts (take averages/avoid parallax error)
what are the 4 ways to judge uncertainties
reading
digital meters
measurement
exam data
how do you measure uncertainty in a reading
you look at the reading once
it will be +/- 0.5 the smallest division
how do you measure uncertainty in a measurement
you look at the reading twice
it will be +/- 1 the smallest division
how do you measure uncertainty in a digital meter
where the measuring device has a digital display
it will be +/- 1 the smallest division
how do you measure uncertainty in exam data
when you dot know how its measured
+/- 1 the smallest significant figure
what is an absolute uncertainty
the uncertainties given with units
what is a percentage uncertainty
the uncertainties are given as a percentage making it easier to compare with values with different units
how do you reduce percentage uncertainty
by decreasing absolute uncertainty or increasing the reading
how do you reduce absolute uncertainty
you use a more precise piece of equipment
eg. micrometer instead of a ruler
how do you increase the reading
by measuring multiple of an object
eg. measuring 10 coins instead of 1
what happens to absolute uncertainty when the measurement is divided by
the absolute uncertainty is divided by the same amount
what happens to uncertainty when you add 2 measurements
you add the absolute uncertainties
what happens to uncertainty when you subtract 2 measurements
you add the absolute uncertainties
what happens to uncertainty when you multiply 2 measurements
you add the percentage uncertainties
what happens to uncertainty when you divide 2 measurements
you add the percentage uncertainties
what happens when you raise a value to a power
you multiply the percentage uncertainty by the power
