Common Sources Of Error In Laboratory

Common Sources Of Error In Lab

There is no such thing as a human error  This vague phrase does not describe the source of error clearly. A careful description of sources of error allows the future experimenters to improve on your techniques. If you find yourself stuck forward while describing sources of error, this list may help.

Incomplete Definition (Systematic or Random)

One reason that it is difficult to make careful estimations is that the estimation isn’t in every case unmistakably characterized. For instance, if two distinct individuals measure the length of a similar rope, they would likely get various outcomes in light of the fact that every individual may extend the rope with an alternate strain. The most ideal approach to limit definition mistakes to deliberately consider and indicate the conditions that could influence the estimation.

Failure to Account for a Factor (Usually Systematic)

The most testing some portion of planning a test is attempting to control or record for all potential elements aside from the one free factor that is being broken down. For example, you may accidentally disregard air opposition when estimating free-fall speeding up, or you may neglect to represent the impact of the Earth’s attractive field when estimating the field of a little magnet.
The most ideal approach to represent these wellsprings of blunder is to conceptualize with your friends pretty much all the components that might influence your outcome. This talk ought to be done before starting the trial so game plans can be made to represent the puzzling components before taking information. Now and again an adjustment can be applied to an outcome subsequent to taking information, however, this is wasteful and not generally conceivable.

Environmental factors (Systematic or Random)

Be aware of the errors introduced by your immediate working environment. You may need to consider for or shield your investigation from vibrations, drafts, changes in temperature, electronic clamor, or different impacts from close by the mechanical assembly.

Instrument resolution (Random)

All instruments have limited accuracy that restricts the capacity to determine little estimation contrasts. For example, a meter stick can’t separate separations to an accuracy obviously superior to about a portion of its littlest scale division (0.5 min for this situation). Probably the most ideal approach to get more exact estimations is to utilize an invalid distinction technique.
Instead of measuring a quantity directly. Null or balance methods involve using instrumentation to measure the difference between two similar quantities, one of which is down very accurately and is adjustable.
The two amounts are then adjusted and the size of the obscure amount can be found by correlation with the reference test. With this strategy, issues of source shakiness are killed, and the estimating instrument can be delicate and doesn’t require a scale.

Check Zero of Instrument (Systematic)

Whenever possible, the calibration of an instrument should be checked before taking the technical data provided by the manufacturer. When making a measurement with data. On the off chance that an alignment standard isn’t accessible, the exactness of the instrument ought to be checked by contrasting it and another instrument that is in any event as exact, or by consulting a micrometer, electronic balance, or an electrical meter, always check the zero reading first.
Re-zero the instrument if conceivable, or measure the uprooting of the zero perusing from the genuine zero and right any estimations appropriately. It is a smart thought to check the zero perusing all through the trial. Physical Variations (Random) T+ is consistently savvy to get numerous estimations over the whole range being vestigated. Doing so regularly uncovers varieties that may somehow go undetected. Whenever wanted, these varieties might be cause for nearer assessment, or they might be consolidated to find an average value.

Parallax (Systematic or Random)

The indicator used to obtain a measurement If the observer’s eye is not squarely aligned. This error can occur whenever there is some distance between the measuring scale and with the pointer and scale, the reading may be too high or low (some analog meters have mirrors to help with this alignment).

Instrument Drift (Systematic)

Most electronic instruments have readings that float after some time. The measure of the float is commonly not worried, however sporadically this wellspring of blunder ‘can be critical and should most electronic instruments have readings that float after some time. The amount of drift is being considered.

Lag Time and Hysteresis ( Systematic)

Some estimating gadgets expect time to arrive at balance, and taking an estimation before the instrument is steady will bring about an estimation that is commonly excessively low. A similar effect is a hysteresis where the instrument readings lag behind and appear to have a memory effect as data are taken sequentially moving up or down through a range of values.
Hysteresis is most commonly associated with materials that become magnetized when a changing magnetic field is applied.


All specimens arriving in the laboratory should be regarded as being potentially pathogenic. It is a very wrong notion to think that only specimens meant for bacteriological investigation are infectious. A specimen of cerebrospinal fluid sent for glucose estimation may be a part of the same specimen sent for bacterial meningitis investigation.
The same is true of a specimen of blood sent for hemoglobin or packed cell volume measurement which may contain infectious microorganisms.

Some of the rules for the laboratory worker are:-

1. Wear closed shoes and not walk barefooted in the laboratory.
2. Allspecimens and infected material should be handled with care.
3. He/she should avoid eating. Drinking or chewing gum in the laboratory.
4. He/she should refrain from smoking in the working zone of the laboratory and also
refrain from applying cosmetics in the laboratory.
5. Nothing should be pipette with the mouth. Gummed labels should not be licked
neither, should pens or pencils be put in the mouth, or stuck in the hair.
6. Protective gloves or plastic aprons should be worn when collecting blood samples
for hepatitis. AIDS or viral hemorrhagic fever investigations.
7. Used needle should be inserted back into its guard immediately after use. But due to the increased awareness of the risks of infection from needle pricks, it is no longer advisable to recap used needles. Instead, sharp safe containers should be made available for immediate disposal of used needles. The containers are finally incinerated.
8. When handling specimens or culture containing highly infectious pathogens gloves
should be worn.
9. Process specimens or cultures containing highly infectious pathogens in the safety cabinet.
10. Any cuts, insect bites, open sore or wounds should be covered with a waterproof adhesive dressing.
11. Fingernails should be kept short.
12. All infected or contaminated materials should be disinfected before disposal.
13. There should be a jar of disinfectant on each bench at the start of the day’s work. The disinfectants must be changed every day.
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