Experimental Analysis

In this article, we are going to discuss the analysis of physical experiments in detail. We are aware that the experiments contain errors, uncertainty, and misconclusions. To avoid that, the need for valid experiment analysis is required. This experimental analysis consists of error analysis. Without using this error analysis, the scientific conclusions may be drawn as invalid in the experiment. 

Experimental analysis

Error analysis

The measurement in physics requires a lot of calculations and calibrations. So, there would be uncertainties and errors. The error can be analysed by the evaluation of uncertainty associated with the measurement theory. The error analysis is much needed and has a major impact on real-life if ignored. Without analysing the error, it is not possible to draw or get a valid conclusion. 

We cannot directly define or describe an error as a bug. It is actually an unavoidable imprecision. Precision and accuracy are the elements of uncertainty.

Process of comparison

In physics, we have the value called standard or ideal value. This standard value is calculated or derived by theoretical analysis. The experimental value is compared with the standard value. This phenomenon happens in error analysis. Either the value should be equal, or it should be within a certain range of prediction values. So, the error can be defined as the difference between the ideal value and the predicted value.

Accuracy

The errors in the measurement can be reduced by the right calibration. The errors are minimised to achieve accuracy in the measurement. It is limited by the least count of the instrument used for the measurement. 

Types of errors

There are three types of errors. They are:

• Constant errors
• Random errors
• Systematic errors

Constant errors

The constant errors occur due to constant reasons. 

For example, you might have some faulty or aged instruments in the laboratory. When using those instruments, you are likely to get some faulty calibration results. It is better to avoid those instruments as much as possible.

Random errors

Random errors occur due to unknown reasons. 

For example, while doing the experiments, unfavourable conditions in the instrument might happen. This leads to incorrect judgments or conclusions. These errors can be reduced by repeating the experiments and calculating the mean.

Systematic errors

The systematic errors occur due to the governance of systematic rule. 

For example, These errors occur at screw gauge – zero error and optical bench – index error. These errors can be minimised by following the systematic rules.

Factors affecting the physical experiments

The following factors affect the experiments in various means:

• Environmental factors
• Calibration failure
• Drift
• Resolution 
• Physical variations
• Parallax
• Lag time
• Hysteresis
• Personal factors

Environmental factors

Environmental factors come under both systematic and random error. This factor is caused by the surrounding conditions. It can be minimised by being aware of environmental errors.

Calibration failure

Calibration failure comes under systematic error. The calibration should be checked once or twice before taking any data.

Drift

Drift comes under systematic errors. The drift is the significant source of error, which most electronic instruments persist. 

Resolution 

This is the factor that comes under random errors. Every instrument has the ability of precision, which omits the small differences.

Physical variations

This factor comes under random errors. This variation can be avoided by taking or repeating the measurement and calculating their mean. It results in a valid conclusion or result. 

Parallax

The parallax factor comes under both systematic and random errors. These errors occur when the eye of the observer is not focusing between the scale and pointer. This leads to faulty reading, either low or high.

Lag time

This factor comes under systematic errors. Lag time is the time that occurs between the equilibrium time and measuring time. When we take the data before the instrument reaches the equilibrium, the data resulting will be somewhat lower than the ideal value. For example, temperature measurement using a thermometer.

Hysteresis

Hysteresis error occurs due to the memory effect of the instrument. The results oscillate between the range of values.  It occurs in the magnetising instrument, because of the application of changing magnetic fields in those instruments. 

Personal factors

Personal errors can be made by humans. This should be avoided and corrected by not avoiding carelessness.

Significant figures

Significant figures are the last two digits of the measured value of physical quality. It results in the correctness of the digits.

Rounding off

Rounding off is the process of removing the superfluous digit in the measured value of the physical quantity, 

Conclusion

In this article, we have seen the need for experimental analysis in physics experiments. The error analysis is the main phenomenon to be followed in the experiments. It will bring serious consequences if this analysis is ignored. We have also discussed the types of errors and the circumstances these errors occur in. We have significant figures and rounding-off methods in experimental analysis.