What factors can change the reading of a barometer?

The correct answer emphasizes three critical environmental factors that significantly influence barometric readings: temperature, humidity, and elevation.

Temperature affects air density and pressure; as the temperature increases, the air expands and becomes less dense, which can lead to a decrease in barometric pressure. Conversely, cooler air is denser, and this can increase the pressure readings. Humidity also plays a role because humid air is lighter than dry air due to the molecular weight of water vapor. When humidity increases, it can result in lower pressure readings on the barometer. Elevation or altitude is another crucial factor because as you ascend in altitude, the air pressure decreases due to the reduction of the weight of the air above you. Therefore, higher elevations result in lower barometric pressure readings.

Understanding these factors is vital for accurate weather prediction and atmospheric studies, as barometers are used to measure atmospheric pressure and help in forecasting weather changes.