Eudiometer

Eudiometer A eudiometer is a device used to measure oxygen content in the air. The tool was developed in 1772 by the British physicist Joseph Priestley in the process of experimenting with various gases, which resulted in discovery of air composition. In fact, in his experiments Priestley discovered many new gases, such as oxygen, hydrogen chloride and ammonia. Depending on the reaction to be measured the device can take different forms. In a most general case, a eudiometer looks like a graduated cylinder, and is most common in two sizes: 50 ml and 100 ml. The upper part of the device is closed, whereas the lower - submerged in water or mercury. In some reactions, two platinum wires (or other nonoxidizable electrodes) are placed into the sealed end so that an electric spark could be generated in between them. An electric spark can initiate a reaction in a gaseous blend, which is then used to determine changes in the volume as a result of the reaction. The device is used similarly to the original barometer, except for the fact that the gas inside displaces a certain amount of liquid that is being used. Today's laboratory eudiometer consists of a glass tube-package with two taps that have electrodes inserted into them through rubber stoppers. The upper and the lower part of the package are closed by the rubber stoppers with glass tubes. The package has marks that divide its volume into equal parts. Despite the fact that the device was invented over 200 years ago, it still continues to be used for laboratory purposes and demonstration of physical experiments.

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Science & Technology