Flashcards in Practical Skills Deck (8)
Name the six S.I base units?
Ignore the candela- for brightness/intensity
K - kelvin
mol - mole
kg - mass
m - metre
s - second
A - ampere
What is meant by the term accurate?
How close a result is to the true value.
What is meant by the term precise?
How closely the repeated results are to one another.
What are errors?
The difference between an individual result and the true value.
What is an uncertainty?
An estimate of the range of values within which the true values lies for a measurement.
What is the absolute uncertainty?
The uncertainty in the quantity (e.g. distance) being measured.
(This is often the resolution of the instrument etc for a vernier calliper +/- 0.01mm)
How can the percentage uncertainty of a single measurement be calculated?
Percentage uncertainty = (Absolute uncertainty / measured value) x 10
Note: using a measurement with a higher resolution (smaller absolute uncertainty) will decrease the percentage uncertainty.