2.1: Physical Quantities and Units Flashcards
What is accuracy?
A measure of how close a measured value is to the true, accepted value. (In practice, the true value usually is not known).
What does it mean if an experiment is accurate?
It means that the experiment result is very close to the true value.
What is validity?
A measure of whether an experimental procedure obtained values that provide an answer to the question being asked.
What does it mean for an experiment to be valid?
It means that the results obtained answered the question asked in the experiment.
What is a random error?
An error that occurs due to unexpected changes during an experiment. These cannot be predicted.
How might a random error affect repeated results?
It can cause repeated results to differ from one another.
What is an anomaly/outlier?
A data point or a value in a set of results that does not fit the trend of data and is therefore an unexpected result.
What may cause an anomaly/outlier?
Random errors during an experiment may cause an anomaly.
What is a systematic error?
An error that occurs due to faults in equipment or the experimental method. Systematic errors cause results to differ by the same amount each time, making them predictable.
What can cause a systematic error?
They can occur if an instrument is not calibrated correctly.
State three ways of reducing random errors.
- Take at least three repeats and calculate a mean average (this increases the likelihood of identifying anomalies).
- Use computers/data loggers
- Use higher resolution equipment
