Which tool would you use to measure air temperature precisely?

• A. Barometer
• B. Thermometer
• C. Hygrometer
• D. Anemometer

Answer: (B)

Measuring air temperature precisely requires a thermometer because it is the instrument designed to respond directly to how hot or cold the air is and to give a numeric reading in degrees. A thermometer uses a substance that expands or changes its electrical properties with temperature, producing an accurate temperature value on a scale you can read or digital display.

Barometers measure atmospheric pressure, which helps with weather forecasting but doesn’t tell you the exact air temperature. Hygrometers measure humidity, the amount of water vapor in the air, not temperature. Anemometers measure wind speed, which is about how fast air is moving, not how hot it is. So for knowing the precise air temperature, a thermometer is the appropriate tool.