uncertainty Flashcards
What equipment do we use
= equipiment that reduces the percentage uncertainty
= increase resoultion of the equipment
= the methid
= the size of increments
What is a reading?
= making a single judgement
= tempertaure, heieigt of liquid,
= sually +- 0.5 tghe smallest scale
What is a measurement?
= desctive a value taken by difference between t2o judgements
= measurements with a tuker judge the start and end postiition
= leads to two points of uncertainty
What are examples of a reading?
= thermometer
= ph meter
= balance
=measuring cylinder
What are examples of a measurement?
= ruler
= stop watch
How to work out the uncertainty in the reading of an instrument with one judgement?
= plus or minus half of the smallest division
How to work out the uncertainty for a measuremrn?
= two judgements
= uncertainty of both judgements,
= if the ruller is mm the ends of the ruler have a 0.5 plus or minus uncertainty so add them together and this is 1
If they give u the value how would u work out uncertainty?
= +1 the last significant digit
= so if 1660 this last signigicant is in the 10ths
=
Why may the uncertainty be lower?
= cannot determine these details of the resolution of the instrument and the method followed
How can we reduce uncertainty for repeated measurements?
= repeating measurements can reduce uncertainty- detect anomalies
= calculate the mean
= calculate the range half the range
= if measurements are repeated
How do we calculate percentage uncertainty of a mewasurement?
= uncertainty / value x 100
How to calculate percentage uncertainty of a repeated measurement?
= uncertaitny / mean value x 100
When we are adding or subtracing what do we do with absoulte uncertainties?
= add them
What do we do if we are multiplying values together?
= add the percentage uncertainities.
= find the percentage uncertainty of each uncertainty
=
What do we do if we are dividing values?
= add the percentageunceratintiies
