Uncertainty

[ibsurvivorhopefully]

is there any easy way of calculating uncertainties with long and tedious formulas? (ex: cylinder V= 1/4 x pi x d² x h)

I've just started IB and uncertainties are confusing me as its only been 3 days and I feel very stressed because i think everyone in my classes finds them really simple 

[Vioh]

is there any easy way of calculating uncertainties with long and tedious formulas? (ex: cylinder V= 1/4 x pi x d² x h)

I've just started IB and uncertainties are confusing me as its only been 3 days and I feel very stressed because i think everyone in my classes finds them really simple 

 

In order to calculate uncertainties for formulas, you can basically follow these four simple rules of propagation of errors:

 

(1) Leave all numbers that have no uncertainties the way they are. These numbers are usually constants.

 

(2) Addition & Subtraction Rule: If or , then

 

(3) Multiplication & Division Rule: If or , then

 

(4) Power & Root Rule: If , then (Note that for roots)

 

(Note that the symbol above represents the absolute error). So let's now use those four rules above to figure out the uncertainty of the volume () in the formula above.

 

Since and are constants, we can simply let them be. Now applying the third and the fourth rule to the right hand side of the equation, we have:

 

 

That's it! Feel free to ask if you have further question!