To determine which of the given options represents a random error, let's first understand the difference between random and systematic errors:
1. Random Error:
- Occurs unpredictably and lacks a consistent pattern.
- Examples include fluctuations in measurements due to varying environmental conditions or human error during multiple measurements.
2. Systematic Error:
- Predictable and consistent, affecting measurements in the same manner each time.
- Examples include instrument calibration errors or consistent procedural mistakes.
Let's analyze each option:
Option A:
- Reversing two numbers when recording a measurement.
- This error, once made, will produce consistently incorrect results. It is not unpredictable but rather a consistent human error. Hence, it's a systematic error.
Option B:
- Miscalibration of a pipette leading to all measurements being off by a specific amount.
- Miscalibration will affect all measurements uniformly and predictably. Therefore, this represents a systematic error.
Option C:
- Not zeroing a weigh boat before measuring the mass of a substance.
- Failing to zero the weigh boat means that every measurement will consistently include the weight of the boat. This is a systematic error as it consistently adds a specific bias to all measurements.
Option D:
- The volume of a liquid in a graduate cylinder being recorded as 10.1 mL and 10.2 mL by different students.
- Different students recording slightly varying volumes indicates small, unpredictable differences in human observation. This variability is characteristic of random error, as it does not follow a consistent pattern.
Thus, the example of random error is:
Answer: D: The volume of a liquid in a graduate cylinder being recorded as 10.1 mL and 10.2 mL by different students.
