How can precision be improved?

Apr 7, 2014

Precision means that we have a number of measurements which are all in close agreement with each other. Different measurement tools will allow for more or less precise measurements.

Let's say you want to measure 100mL, which piece of lab equipment should you select?

A 100mL beaker has an uncertaintly of ±5%. So one measure that you believe to be 100mL might actually be 95mL. A second measure you believe to be 100mL could actually be 105mL. A beaker would be a bad choice for precise measurements of this volume.

A 100mL graduated cylinder has 1mL increments, so the decreased uncertainty* of this tool for measuring 100mL will ensure that your measurements are much more precise.

*You'll find different opinions about determining the uncertainty for a 100mL graduated cylinder. Some people will say that the uncertaintly of this tool is 1/2 the increment. That would make the uncertainty ±0.5mL

The graduated cylinder is a much better tool for precise measurements because of its smaller uncertainty because now your possible range of volume for multiple measurements attempting 100mL will range from 99.5mL - 100.5mL, much better than the beaker range of 95-105mL.