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Online Chemistry Labs | Learning Objectives

Background:

This introductory exercise introduces students to experimental error, variability, and its measurement and significance in experimental work. Our virtual instruments are designed to simulate both random and systematic errors, and error can be controlled for each instrument in each lab. For instance, as the balance displays the mass of an object, the student will observe random fluctuations in the displayed value due to simulated electronic and vibration noise. In addition, an offset error can be introduced as well as a linear systematic percentage deviation from the "true" mass.

OLL Error Figure 2

 Learning Objectives:

  1. Introduce the concept of measurement error. 
  2. Illustrate how scatter in replicate measurements or the properties in comparable objects can be quantified by calculating the standard deviation, σ.
  3. Illustrate the 68% and 99.7% expectation of σ and 3 σ in random errors.
  4. Compare and analyze the relative significance of measurement error and variability in a sample set.
  5. Understand the difference between systematic and random error sources.
  6. Demonstrate the ability to calculate σ algebraically, and by using functions available in programs like Excel and Open Office Calc.