1. Instrument limitations:
* Resolution: The smallest increment the instrument can measure. A ruler with millimeter markings has lower resolution than one with markings in tenths of a millimeter. Lower resolution leads to lower accuracy.
* Sensitivity: The ability of the instrument to detect small changes in the measured quantity. A less sensitive instrument might miss subtle variations, leading to inaccuracies.
* Calibration: If the instrument isn't properly calibrated, its readings will be systematically off. A miscalibrated scale will always give inaccurate weight readings.
* Zero error/offset: A systematic error where the instrument doesn't read zero when it should. This leads to a constant offset in all measurements.
* Drift: Gradual changes in the instrument's readings over time, even without changes in the measured quantity. This is common in electronic instruments.
* Linearity: Ideally, an instrument's response should be linear (a straight line relationship between input and output). Non-linearity introduces errors.
* Hysteresis: Differences in readings depending on whether the measured quantity is increasing or decreasing.
2. Environmental factors:
* Temperature: Temperature changes can affect the dimensions of measuring instruments and the properties of the material being measured.
* Humidity: Humidity can affect the accuracy of some measuring instruments, particularly those involving electrical components or sensitive materials.
* Pressure: Changes in atmospheric pressure can influence measurements, especially those related to volume or gas flow.
* Electromagnetic interference (EMI): EMI can affect the readings of electronic measuring instruments.
* Vibration: Vibrations can cause instability and inaccuracies, particularly in delicate measurements.
3. Human error:
* Parallax error: Error caused by not viewing the measurement at eye level, leading to an inaccurate reading.
* Misreading the scale: Errors from incorrectly interpreting the markings on the instrument.
* Improper handling of the instrument: Rough handling can damage the instrument and affect its accuracy.
* Observer bias: The observer's expectations or preconceptions might influence their reading.
* Insufficient sampling: Measuring only a few samples might not be representative of the entire population, leading to inaccurate conclusions.
4. Methodological errors:
* Incorrect procedure: Following the wrong procedure or not following the procedure precisely.
* Insufficient precision: Not making measurements to a fine enough degree.
* Inappropriate instrument: Using the wrong instrument for the measurement.
* Systematic errors: Errors that consistently occur in one direction (e.g., always overestimating).
* Random errors: Errors that occur randomly and can be positive or negative.
Minimizing errors requires careful consideration of all these factors, choosing appropriate instruments, using proper techniques, and understanding the limitations of the measurement process. Statistical analysis can also be used to assess the accuracy and precision of measurements and identify potential sources of error.