Chapter 1C Measuring Weather
1. How does sunlight affect air temperature?
The angle of sunlight and the number of daylight hours affect air temperature.
Different surfaces on the earth heat the air at different rates.
A theremometer measures air temperature.
2. How does temperature affect air movement?
Changes in air temperature cause changes in air pressure and wind.
A barometer measures air pressure.
A wind vane measures wind direction. An anemometer measures speed.
3. What causes clouds and precipitation?
Clouds form when water vapor in the air condenses into tiny water drops.
Clouds have different sizes, shapes, and colors, and they form at different heights.
Rain, snow, and hail are three kinds of precipitation.
A hygrometer measures humidity. A rain gauge measures precipitation.
Evaporation, condensation, and precipitation move water through the water cycle.
4. How do meteorologists predict weather?
An air mass is a large body of air. A front is where two air masses meet.
Meteorologists use information from the National Weather Service, maps, and weather instruments to track and predict weather.
Meteorolgists' predictions provide people time to take precautions to keep safe during severe weather.
Low-pressure area a place where warm air rises and pushes down on the earth’s surface with less pressure
High-pressure area a place where cool air sinks and pushes down on the earth’s surface with more pressure
Barometer a tool that measures air pressure
Wind vane a tool that shows wind direction
Anemometer a tool that measures wind speed
Precipitation moisture that falls from clouds to the ground
Rain gauge a tool that measures precipitation
Humidity amount of water vapor in the air
Hygrometer a tool that measures humidity
Air mass a large body of air that has about the same temperature and humidity
Front the line were two air masses meet
Forecast a prediction of what the weather will be like
Meteorologist a person who studies weather
National Weather Service a government agency that collects information about weather