Uncertainty In Data

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Accuracy Noun

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[ak-yer-uh-see]

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Accuracy

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A measure of how close a measured value is to the true or accepted value, indicating the correctness of a result.

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Example: This diagram uses a target to show accuracy as how close measurements (the dots) are to the true value (the bullseye).

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Precision Noun

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[pri-sizh-uhn]

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Precision

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A measure of how close a series of measurements are to one another, indicating the reproducibility of the measurement.

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Example: This image uses targets to show precision as how close multiple measurements (shots) are to each other, even if they are not close to the center.

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Experimental Value Noun

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[ik-sper-uh-men-tl val-yoo]

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Experimental Value

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A quantitative value that is measured and determined during the course of a scientific experiment or observation.

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Example: This image shows multiple thermometers measuring the same room's temperature. Each thermometer's reading is an 'experimental value,' and their slight differences demonstrate measurement uncertainty.

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Accepted Value Noun

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[ak-sep-tid val-yoo]

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Accepted Value

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A value that is considered true and correct, often used as a standard for comparison in scientific experiments.

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Example: Torricelli's barometer shows that standard atmospheric pressure supports a mercury column of 760 mm, a universally accepted value used for scientific comparison.

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Error Noun

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[er-er]

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Error

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The calculated difference between an experimental value and the corresponding accepted value, which quantifies the degree of inaccuracy.

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Example: A faulty measuring tool, like a broken tape measure, leads to an incorrect measurement, which is a type of measurement error in data collection.

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Percent Error Noun

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[per-sent er-er]

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Percent Error

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A measure of the error expressed as a percentage of the accepted value, indicating the relative size of the error.

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Example: This image shows how to calculate percent error by comparing a measured value (48 inches) to an accepted, true value (50 inches), showing the difference as a percentage.

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Significant Figures Noun

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[sig-nif-i-kuhnt fig-yerz]

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Significant Figures

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The digits in a measurement that are known with certainty plus one estimated digit, indicating the measurement's precision.

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Example: This diagram uses color-coding to show the different types of digits in a number, helping to identify which ones are significant.

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Density Noun

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[den-si-tee]

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Density

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An intensive physical property of a substance, calculated as the ratio of its mass to its volume.

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Example: This experiment shows how objects float or sink based on their density compared to the liquids. The less dense cork floats on oil, while the denser padlock sinks in water.

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Scientific Notation Noun

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[sahy-uhn-tif-ik noh-tey-shuhn]

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Scientific Notation

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A method of expressing very large or small numbers as a product of a coefficient and a power of 10.

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Example: This diagram shows how to write very large or very small numbers using scientific notation by breaking it down into a coefficient, a base of 10, and an exponent.

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Tolerances Noun

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[tol-er-uhn-siz]

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Tolerances

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A narrow range of allowable dimensions or values based on an acceptable amount of error, often used in manufacturing.

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Example: This table shows manufacturing tolerances, the acceptable range of error in a part's size. For example, a small part might have a tolerance of ±0.2 mm.