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Tools Used for Measuring Weather
- Thermometers and barometers are simple tools still used to measure weather.barometer image by Alex White from Fotolia.com
Tools used for measuring the weather have gotten increasingly sophisticated, but the basic science behind this high-tech equipment has remained virtually the same. Amateur weather forecasters can still provide reliable results based on the tools that have been used for centuries.
- The thermometer is used to measure the temperature. Most thermometers today rely upon either alcohol or liquid mercury for measurement because both substances expand reliably when heated and contract when cooled. It is the measurable rate of expansion and contraction that occurs regularly as the temperature rises or falls that makes alcohol and mercury ideal for thermometers even in the digital age.
- Along with the thermometer, the barometer is one tool used to measure equipment that can be found in many homes. A simple aneroid barometer measures air pressure fluctuations by using a vacuum capsule made of steel or beryllium. The capsule compresses when air pressure rises and expands when the pressure falls. This movement of the capsule is read by a set of levers that create graphs that can be plotted to measure changes in the pressure.
- Rainfall amounts are measured by using a rain gauge. The most effective rain gauges place the stem of a funnel within a jar or bottle with a narrow neck. This helps to prevent evaporation that can affect the accuracy of the count. Accuracy is important in gauging rainfall because gauges can also be affected by wind patterns that are in turn affected by trees, buildings and topographical features.
- An anemometer is the weather tool used for measuring wind. Simple anemometers can be made by mounting paper cups on a central rotating shaft. The wind pushes against the interior of the cup and the number of rotations made indicates the speed of the wind. Electronic anemometers are used to provide a continuous record of the speed of wind as well as to provide a more immediate and accurate measurement.
- Humidity is a weather element that is measured by a tool known as a hygrometer. The amount of moisture in the air is calculated by comparing temperature readings recorded by a wet-bulb thermometer and a dry-bulb thermometer. The comparison results from the difference in the temperature of saturated air with the actual temperature. If both thermometers read the same, it means there is a relative humidity of 100 percent.
Campbell-Stokes Sunshine Recorder
- The Campbell-Stokes sunshine recorder is a tool used to measure duration and intensity of sunshine. A glass sphere is used to focus and magnify light from the sun onto a special card. The card is fire-retardant and if the sunlight is bright enough a trace will be burned onto the card. The longer the length of this trace, the more sunshine there has been that day.