No doubt your teacher will have spoken to you about the importance of errors / uncertainties in lab work – but why all the fuss? Doesn’t it matter if that titration is nearly correct? A few extra drops of reagent here or a slightly over filled volumetric flask there won’t matter – will it?
Well errors do matter and they do become a bit of a problem – here is why:
In September 2011, the scientific world quaked in its boots (for a while) – scientists in Italy had found that some neutrinos had arrived at their detector sooner than they should have. The neutrinos in question had come from CERN in France /Switzerland and were being sent South West, underground to Italy (but let’s not get too bogged down by the detail).
So what? Well, a neutrino moves at the speed of light. Not ‘round about’ the speed of light or ‘just a bit under’ the speed of light but at exactly the speed of light.
This meant only one thing – to arrive sooner than expected they needed to be travelling faster than light … which was thought of as being impossible.
The implications were huge – massive – almost unthinkable. They really were shocking. If true, it would have meant that in your lifetime you would have witnessed the biggest ever scientific discovery of all time – of the entire universe! Time travel would become possible (in theory) and all interesting things could have happened – you may have ended up meeting your grandchildren when they were older than you.
The scientists knew something was wrong … or did they? They thought something was wrong …. Or was it?
From the data they had, the results showed (within the calculated random errors) that the neutrinos were going faster than light but something must have been wrong. So the scientist looked and looked … and when their looking didn’t give them any answers – they asked the outside world for help – could the results be verified or could the systematic error be found?
I do find this asking for help quite amusing – instead of boldly announcing ‘we’ve done it, we have discovered the impossible’ they actually were really humble about it (almost embarrassed) more of a ‘um, look guys, we’ve got these ground breaking results that can’t possibly be correct – help us find out where we have gone wrong, please!’
So what happened? Well, as you have probably guessed, in the end, the systematic errors were found – there were two, the timing gear and an optical fibre connection but it cost the head of the experiment his job!
And the relevance (as there is not a bit of chemistry here, I know!) – This is a great example of the Nature of Science in action.
NOS statement 3.3 states:
“Scientists need to be aware of random errors and systematic errors, and use techniques such as error bars and lines of best fit on graphs to portray the data as realistically and honestly as possible. There is a need to consider whether outlying data points should be discarded or not.”
If our scientists had not been aware of systematic errors they would have thought they had made the biggest breakthrough of all time – they did however know about them and even though they couldn’t find them they acknowledged they were there somewhere.
Which also ties in with NOS statement 4.4:
“Scientists spend a considerable amount of time reading the published results of other scientists. They publish their own results in scientific journals after a process called peer review. This is when the work of a scientist or, more usually, a team of scientists is anonymously and independently reviewed by several scientists working in the same field who decide if the research methodologies are sound and if the work represents a new contribution to knowledge in that field.”
So next time your teacher moans at you about errors and uncertainties – try to see where your teacher is coming from. You may not lose your job like the head of the above experiment but it may stop you from masking some incorrect statements about your lab work! J