BRAINCAKERandom Errors and Systematic Errors
Errors fall into two types, and each one is dealt with differently.
Random errors make readings scatter unpredictably above and below the true value. They come from things that vary from one reading to the next, such as judging the exact bottom of a meniscus, slight changes in when the end point is judged, or small draughts affecting a balance. Random errors reduce precision. Because they are equally likely to be high or low, they can be reduced by repeating measurements and taking a mean.
Systematic errors shift every reading by the same amount in the same direction. Examples:
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Key terms in this lesson
- zero error
- A systematic error where an instrument does not read zero when the true value is zero, for example an unzeroed balance.
- precision
- How close together repeated measurements are to each other, shown by how little they scatter.
- accuracy
- How close a measured value is to the true or accepted value.
More in Errors and Uncertainties
- Errors vs Mistakes
- Accuracy and Precision
- Uncertainty
- Percentage Uncertainty
- Adding Uncertainties
- Adding Percentage Uncertainties
- Minimising Errors and Uncertainties
- Percentage Yield
All 14 lessons in Errors and Uncertainties · All Edexcel AS-level Chemistry topics