Used to measure wind

Answer 1

• Wind speed is an important factor in a variety of fields, including maritime operations, civil engineering and weather forecasting. The device used to measure wind speed is called an anemometer. Quantitative measurements of wind speed were first made with anemometers as early as the 15th century. Modern weather services use adaptations of the anemometer that incorporate modern technologies like lasers or ultrasound sensors to increase measurement precision and repeatability. Two types of anemometers are used; namely cup anemometers and hot wire anemometers.

• Though basic in construction, the cup anemometer introduced in 1846 is considered an industry standard in measuring wind speed. Modern variants of this technology use three cups that spin around a vertical axis. The torque generated by the movement of wind is proportional to the wind speed. Cup anemometers must be calibrated because the torque also depends on the geometry of the cups used and the length of the arms they are attached to. Cup anemometers are relatively inexpensive and simple to construct, making them a popular project for science fairs.

• Hot wire anemometers exploit the electrical properties of metals to indirectly measure wind speed. The electrical conductivity of a metal wire is proportional to the temperature of the metal. A hot wire anemometer is essentially a fine metal wire that is heated above ambient temperatures. When wind blows, the wire is cooled, measurably reducing its conductivity. The degree to which the conductivity is reduced is proportional to the velocity of the wind. Hot wire anemometers are small and require electrical measurement equipment to use effectively.

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Answer 2

It is a wind sock.