Uncertainty in Measurement

Measurements are made in scientific laboratories, and are commonly used in scientific calculations. To carry out scientific calculations properly it is important to discuss the following concepts;

• Accuracy
  • refers to the agreement of a particular value with the true value.
• Precision
  • refers to the degree of agreement among several measurements of the same quantity.
  • Sample animation differentiating between accuracy and precision.
• Exact numbers
  • those numbers that we know exactly. Counting objects is an experiment that can be carried out with complete accuracy.
• Uncertainty
  • . numbers that are not known exactly. When we measure lengths (of an object), volumes (of a liquid) or masses (of a solid) the measurements are not exact, they have some degree of uncertainty.
• Sample animation demonstrating uncertainty in measurement.

Significant figures