11.1 Determine the uncertainties in results [SL IB Chemistry]

If you add or subtract data then the uncertainties must also be added. Multiplication or division of data means that the percentage uncertainties must be added.

This is version 5 of the video -- no other video has given me this much trouble or dare I say it uncertainty...

[LiquidCandy]

i am uncertain as to whether or not this video helped me.

[aytaj]

This video is just amazing. I wasted so much time watching other "helpful" videos trying to understand this topic. Thank you for the explanation.

[AlexPiotrowski]

wait so are all these example dealing with dependent errors?
i thought to calculate the density of that object, the errors are independent (one comes from mass and the other comes from volume)?

is it better just to use dependent errors in all questions?

also thanks for the video, now i can multiple and divide.

[Cristina-cqhv]

Literally saved my life, thank you so much!!!

[StarCai]

For the part during 8:00, if you have an uncertainty that has, let's say hundredth place: 3.0 plus minus 0.24 g then do you add a zero to the 3.0 making it 3.00?

[bherrnnyk]

yoo you literally turned my teacher's work into bullshit thanks fr
keep it up man...

[kiip]

The second last example: average of 3 uncertainties
10.5±0.1m, 12.5±0.1m, 10.0±0.1m is 11.0±0.1m



If I simply calculate the uncertainty of 10.5m, 12.5m, 10.0m

average = (10.5m+12.5m+10.0m)÷3 = 11.0m

uncertainty = (max-min)÷2 = (12.5m-10.0m)÷2 = 1.25m = 1.3m (round to 1 dp)

so I would get 11.0±1.3m



How do I relate 11.0±0.1m with 11.0±1.3m?

How do I calculate an uncertainty of uncertainties?

[themikebroadhead]

Shouldn't students assume some uncertainty (ie, +/- 0.01) in the ideal gas constant rather than ignore it?

[vvxyow]

How do you work out uncertainty when you have to add/subtract and multiply/divide at the same time, for instance, if you have to input values into an equation?

[ayomiajibade]

Hey, I get this could you make a video explaining uncertainties when it comes to making a standard solution and doing a titration please please please please !!

[minihillary]

So all uncertainties should only have 1s.f., regardless of whether it is an absolute uncertainty or a percentage uncertainty?

[ladyluuuna]

where did you get the 0.500 kg/l from?

[mcluk]

Dear Sir, , Could you please help me? I have got a Physics practical exam on Monday. could you please help me with following questions?? IN CALCULATING g (gravity) by free fall using a timer

Q1 how to comment on the accuracy of my value of results?
is the experimental valuse realistic?? how I know this??
why take several measurements??
why plot a graph and calculate ''g'' from it??
why not find several ''g'' values from h=1/2gt2?? and calculate a mean average for ''g''??
which measurements of time and height show the greatest errors?? why??
if you were to improve the experimental technique which variable would you choose to aim to measure more precisely?? justify your decision??

COULD YOU PLEASE HELP ME WITH THESE QUESTIONS??

THANK YOU!!

[sadhanakoganti]

Hey! Mr.Thornley
Could you please please please make a video of how to calculate total uncertainties (in percentages) for lab works and enthalpy calculations, etc.
Thanks!!!! (:

[spencerpencer]

Is it just me or is your first question asked wrong? If you have a measurement of 9.0 cm how can you have an uncertainty of 0.05? Errors have to be reported to the same precision as the measurement. Am I wrong?

[fedoras]

What if you are dividing a number with an uncertainty by a number without an uncertainty? Do you just divide the uncertainty in the same way?

[daianabilbao]

/what about uncertainty with time? like seconds.. plus or minus what?

[adijain]

If you divide the same uncertainties, do they cancel out or add up?

[lovelight]

Shpuldnt you square the uncertainties prior to adding then take the square root of the sum?

[sushislushier]

Can you explain the differences for IB physics?