How do you report a measurement with uncertainty?

Report the measured value using the correct number of significant figures and include an explicit uncertainty if possible, for example nineteen point eight five plus or minus zero point zero one milliliters.

When you measure something, think of the number as two parts: the best value you found and how sure you are about it. The best value is written with only the digits that are meaningful, which we call significant figures, and the uncertainty tells how much that number might wiggle. If you can, give the uncertainty as a plus or minus number with the same unit, and make sure the uncertainty is written to one or at most two significant figures so it does not pretend to be more precise than your tools allow. Match the decimal places of the measured value and the uncertainty so the numbers line up and are easy to compare.

A common mistake is writing too many digits and pretending your measurement is more accurate than it really is, which makes the number misleading; the fix is to round the result to the precision implied by the uncertainty. Another frequent error is giving an uncertainty with too many significant figures, which confuses people about the true precision; report the uncertainty with one or two significant figures and round the measured value to the same decimal place. Some students forget to include units or write inconsistent units between the value and uncertainty, so always include the same unit for both parts.

For more examples and video explanations go to w w w dot gumball degree dot com to find additional resources and worksheets on reporting measurements with uncertainty.

Reporting Measurements with Uncertainty

1. Write the best measured value
2. Use correct significant figures
3. Provide an uncertainty value
4. Uncertainty as plus or minus
5. Uncertainty one or two sig figs
6. Match decimal places of values

Common Measurement Mistakes

1. Reporting too many digits
2. Uncertainty with too many sig figs
3. Missing or inconsistent units

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