A device for measuring the rainfall in a specified period, usually one day. A standard gauge comprises a cylinder 20cm in diameter, with an upper surface in the shape of a funnel, set vertically on open ground with its upper rim 1m above ground level. Rain flows through the funnel into a measuring tube 6.32cm in diameter. The depth of water in the tube is 10 times the rainfall amount. In an alternative design, water passes from the first funnel to a second, smaller funnel, and from there to one of two ‘tipping buckets’. When one bucket is full, it descends, makes an electrical contact, and empties itself, while the second bucket is positioned to collect water. Because the buckets make an electrical contact each time they collect a predetermined weight of water the rain gauge provides a record of rainfall and does not require regular emptying.
Subjects: Ecology and Conservation — Earth Sciences and Geography.