In the visual comparison method, what materials are used to compare samples?

In the visual comparison method, Nessler tubes are specifically designed for comparing the color intensity of liquid samples. This method typically involves adding a reagent to the sample, which produces a color that can be visually compared against a standard scale or a blank sample in a Nessler tube. The shape and characteristics of Nessler tubes facilitate consistent viewing and comparison of the color, making them an ideal choice for this type of analysis.

Other materials like pipettes, burettes, and beakers serve different purposes in laboratory settings, such as measuring or transferring liquids or containing samples, but they do not provide the specific properties necessary for accurate visual comparison of color intensity in the context of this method.