Flashcards on Understanding Experimental Uncertainty and Evaluation
Understanding Experimental Uncertainty and Evaluation
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Experimental Uncertainty and Evaluation
17 cards
Card 1
Question: What is 'uncertainty' in the context of experimental measurements?
Answer: Uncertainty is the amount of error a measurement or result might have — each result has some uncertainty due to random error and equipment limits.
Card 2
Question: Why do repeated measurements often give slightly different results?
Answer: Because of random error: small unpredictable variations each time you repeat a measurement.
Card 3
Question: How does the resolution of equipment affect measurements?
Answer: Limits in the resolution of equipment introduce uncertainty because the instrument can only resolve values to a certain precision.
Card 4
Question: How do you calculate the uncertainty of a set of repeated measurements using the range method?
Answer: Uncertainty = range / 2, where range = largest value − smallest value.
Card 5
Question: Using the example values 20.1, 19.8, 20.0 cm³, what is the range?
Answer: Range = 20.1 − 19.8 = 0.300 cm³.
Card 6
Question: Using the same example (20.1, 19.8, 20.0 cm³), what is the uncertainty of the mean?
Answer: Uncertainty = range / 2 = 0.300 / 2 = 0.150 cm³, so mean = 20.0 ± 0.150 cm³.
Card 7
Question: How are uncertainties usually shown when reporting a measurement?
Answer: Uncertainties are shown using the '±' symbol (for example 20.0 ± 0.150 cm³).
Card 8
Question: What does a larger range of repeated measurements indicate about precision and uncertainty?
Answer: A larger range indicates less precise results and greater uncertainty.
Card 9
Question: How can measuring a greater amount or over a longer period affect percentage uncertainty?
Answer: Measuring a greater amount or over a longer period reduces the percentage uncertainty in the results.
Card 10
Question: What should an evaluation of an investigation comment on regarding the method?
Answer: Whether the method was valid, whether other variables were controlled, and whether the test was fair.