Defining Accuracy in Measurement
Accuracy refers to how close a measured value is to the true or accepted value of a quantity. A highly accurate measurement yields a result that is very near to the actual value, indicating a minimal degree of systematic error in the measurement process. It reflects the correctness of the measurement.
Defining Resolution in Measurement
Resolution, also known as discrimination or readability, is the smallest increment of quantity that an instrument can detect or display. It describes the level of detail or fineness of a measurement. For instance, a ruler marked in millimeters has a higher resolution than one marked only in centimeters because it can distinguish smaller changes.
The Key Difference Between Accuracy and Resolution
The primary difference lies in what they describe: accuracy indicates the correctness of a measurement (closeness to truth), while resolution indicates the smallest discernible step in a measurement (fineness of detail). A measurement can have high resolution (many decimal places or small increments) but be inaccurate (far from the true value due to error), or it can be accurate but have low resolution (close to the true value but only expressed coarsely).
Why Both Matter: A Practical Example
Imagine weighing an object using a digital scale. If the scale displays '10.000 g' (high resolution) but is poorly calibrated and consistently reads 1.000 g higher than the object's true weight, then your measurements are high resolution but low accuracy. Conversely, an old analog scale that reads '10 g' (low resolution) might consistently be very close to the true value, making it accurate but coarse. For reliable scientific results, both high accuracy (correctness) and appropriate resolution (detail) are essential to capture precise, meaningful data.