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CE: Human Errors


dessskris

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As we all know, there are 3 types of error in the sciences:

1. Systematic error

2. Random error

3. Human error

Where the third one is not an appropriate type of error to be discussed in the Conclusion&Evaluation part in lab reports.

My question is what are the examples of human errors? I only know a few but I am not sure on that anymore because I forget :P

For example, last week I did a Chemistry experiment. I understood the procedure wrongly and I repeated the experiment after my teacher explained to me what I was actually asked to do. This wasted my time and I ended up not finishing the experiment. So we will continue the experiment tomorrow (4 out of the 5 of us made mistakes haha). Now, is this counted as a human error? Why?

Thank you

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Human error hinges on the experimenter doing the experiment truly to the best of his ability, but being let down by inexperience. Examples of human errors include writing down balance values incorrectly. In a nutshell, human error is the error made by an individual with respects to perception and/or miscalculation. That's my opinion.

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Human errors are errors done by you. For example, here's a quote from my best friend's lab, she got very good on her IAs:

Human error when stopping the clock: a person’s hand-eye coordination differs from one person to another, thus how fast one person might stop clock would affect the time given for the reaction to take place; the more time available, the more electron transfer is expected to take place and hence the greater the change in mass of the anode. To ensure that results are as accurate as possible, the same person should be in charge of stopping the clocks for all trials.

Here are other examples:

1) if an experiment requires constant stirring, the person may not be able to stir the whole time..so they'll stop once in a while or go slower at times and faster at others.

2)Wrong measurement readings, for example when you're reading a measurement on a burette, as you know you have to take the reading at the eye level just on the meniscus. Many people make the mistake of not taking it at the eye level which may add or subtract 0.5 cm3 or so to the original reading.

3)When you're using a pipette to measure a certain volume into a test tube, after you get the correct volume and are about to move it to the test tubes, if you're not very careful, a drop or two may not make it into the test tube.

4) If an experiment requires you to keep the beaker or test tube very still, you might accidentally hit the test tube rack or something.

So anything of that sort, just look at every step in your experiment and think about anything you could accidentally do.

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A fundamental one is measuring a liquid in a cylinder. You must measure it at the bottom of the meniscus and not the top. That is human error because humans are retarded and don't do as they're supposed to.

Hehehe...loved the part about humans! Of course....the meniscus is the most obvious of obvious examples. :(

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Ok thanks people. What about my other question?

For example, last week I did a Chemistry experiment. I understood the procedure wrongly and I repeated the experiment after my teacher explained to me what I was actually asked to do. This wasted my time and I ended up not finishing the experiment. So we will continue the experiment tomorrow (4 out of the 5 of us made mistakes haha). Now, is this counted as a human error? Why?

Yeah my teacher told me not to include human error in the CE too.

Systematic errors are errors regarding the procedure, IMO. For example you are asked to heat it but you even burn it or evaporate it all. Or maybe you're supposed to dilute it first (by adding distilled water) but you don't dilute it and just go to the next procedure straight away.

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Human errors are to do with the operator’s incompetence or inexperience. A systematic error occurs when there is something inaccurate about the experiment itself, even when the operator performs all instructions correctly and random uncertainties are not taken into account. A classic example would be heat loss, where all the heat doesn’t go into the substance you are heating thus giving a lower temperature increase than the actual increase. There’s nothing the operator can do to accommodate this error, nor can the precision of equipment change this outcome.

So not reading the instructions properly does count as a human error. It’s the same as the ‘meniscus’ example except to a more general situation.

Edit: Actually there are some cases were you can incorporate the human error into the random uncertainty. For example, I think someone mentioned above the use of a stopwatch. To take the random uncertainty of a stopwatch to be 0.01 seconds is ludicrous so you would normally incorporate the human error element into it to give a result of e.g. 5 seconds +/- 0.5 or 1s.

Edited by Keel
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