What does an Anemometer Measure — Reading Comprehension

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This comprehensive science passage, suitable for middle school students, defines what an anemometer is and explains its core function: measuring wind speed. It details the mechanics of the common cup anemometer, where spinning cups count rotations to determine wind velocity. The passage also introduces the hot-wire anemometer and its different method of measurement. Real-world connections are emphasized, highlighting the importance of anemometers in various fields, including meteorology for weather forecasting, aviation for flight safety, engineering for structural design, and the renewable energy industry for wind farm placement and efficiency. The content aligns with NGSS physical science standards related to energy and engineering design, providing students with a solid understanding of how a scientific instrument works and its societal relevance.

CONTENT PREVIEW

Anemometer-Measure — A cup anemometer, a common instrument used in weather stations, spins to measure the speed of the wind.

An anemometer is a scientific instrument specifically designed to measure wind speed. The name comes from the Greek word anemos, meaning "wind." Anemometers are crucial tools for meteorologists, pilots, and engineers because understanding wind speed is essential for forecasting weather, ensuring safe travel, and designing structures. While you might not see one every day, they are a fundamental part of a weather station's equipment, providing the data needed to understand and predict atmospheric conditions.

The most common type of anemometer is the cup anemometer. This device features three or four hemispherical cups mounted on horizontal arms that rotate around a vertical axis. When the wind blows, it catches the cups and causes them to spin. The stronger the wind, the faster the cups rotate. The anemometer then counts these rotations over a set period. This rotational speed is then converted into a wind speed measurement, typically in units like miles per hour (mph), kilometers per hour (km/h), or knots. This simple yet effective design provides a reliable way to measure the average wind speed over a short time.

Beyond weather forecasting, anemometers have many real-world applications. Pilots use them to assess wind conditions for safe takeoffs and landings. Engineers use anemometers to test the effects of wind on buildings, bridges, and other structures to ensure they are strong enough to withstand high winds. The renewable energy industry also relies on them heavily; anemometers are used to determine the best locations for wind farms and to monitor the performance of wind turbines. The data collected helps maximize energy production and prevent damage from excessive wind speeds.

A different type of anemometer, the hot-wire anemometer, measures wind speed by a different principle. It uses an electrically heated, thin wire. As air flows past the wire, it cools it down. The amount of electrical current needed to maintain the wire at a constant temperature is then used to calculate the wind speed. This type of anemometer is particularly useful for measuring very low air speeds and is often used in scientific research or to monitor airflow in ventilation systems.

Fun Fact: The first known description of a simple anemometer dates back to 1450, by the Italian artist and architect Leon Battista Alberti.

What is the primary function of an anemometer?

To measure air pressureTo measure wind speedTo measure wind directionTo measure temperature

The word "anemometer" is derived from a Greek word meaning which of the following?

SkyStormAirWind

How does a cup anemometer typically measure wind speed?

By measuring the force of the wind on a flat plateBy counting the number of rotations of its cupsBy measuring the angle of a swinging diskBy monitoring the cooling effect on a heated wire

Which of the following is a real-world application of an anemometer mentioned in the passage?

Measuring the depth of rainfallPredicting the arrival of a hurricaneDetermining the best location for a wind farmCalculating the air quality in a city

A hot-wire anemometer calculates wind speed based on which principle?

The speed of sound traveling through the airThe amount of light blocked by a spinning propellerThe force exerted on a rotating cupThe amount of electrical current needed to keep a wire hot

Why might an engineer use an anemometer when designing a new skyscraper?

To ensure the building can withstand high windsTo measure the building's internal temperatureTo determine the building's geographic locationTo calculate the building's weight and mass

What is the main idea of the reading passage?

To explain the history of weather instrumentsTo describe different types of weather patternsTo define an anemometer and its usesTo argue for the importance of renewable energy

Based on the passage, if the cups on a cup anemometer are spinning very quickly, what can you infer about the wind?

The wind is blowing gently.The wind is changing direction.The wind is moving at a high speed.The wind is creating high air pressure.