Weather Instruments

CONTENTS

Think About . . . What Causes Earth’s Weather? ...... 2 How Do We Measure Air Temperature? ...... 3 How Do We Measure Air Pressure? ...... 4 How Do We Measure Wind? ...... 5 What Causes Clouds and Precipitation? ...... 6 How Do We Measure Humidity? ...... 7 How Do We Measure Precipitation? ...... 8 Other Weather Instruments ...... 9

People in Science Gabriel Fahrenheit ...... 10 Anders Celsius ...... 10 Sir Francis Beaufort ...... 11 Airport Meteorologists ...... 12

Did You Know? How Thermometers Work ...... 14 About Wind Chill ...... 15

Glossary ...... 16

air mass body of air that has about meteorologist scientist who studies the same temperature and humidity the weather throughout precipitation any form of water air pressure force of the atmosphere that falls from clouds to Earth pushing down on Earth rain gauge instrument used to measure anemometer instrument used to the amount of precipitation measure the speed of the wind stationary front place where a cold atmosphere layer of air surrounding air mass and warm air mass meet, Earth but neither moves barometer instrument used to stratus cloud low, layered cloud measure air pressure temperature measure of the amount Beaufort scale scale that relates wind of heat energy in a substance speed to its effects on land and sea thermometer instrument used Celsius type of temperature scale to measure temperature cirrus cloud thin, feathery cloud troposphere bottom layer of Earth’s made of ice crystals atmosphere where weather occurs cloud mass of tiny water droplets warm front the leading edge of a or ice particles in the air moving mass of warm air cold front leading edge of a moving water cycle constant movement of mass of cold air water from Earth to the atmosphere, condensation the process of a gas and back to Earth changing to a liquid water vapor water in the form of a gas cumulus cloud puffy cloud weather state of the atmosphere at a evaporation the process of a liquid certain place and time changing to a gas weather map map that shows weather Fahrenheit type of temperature scale conditions over a large area front boundary between air masses wind moving air with different temperatures wind chill how cold the air feels humidity the amount of water vapor because of the wind in the air wind vane instrument used to tell the hygrometer instrument used to direction from which the wind is blowing measure humidity © Delta Education LLC. All rights reserved.