Weather & Climate

Science, Grade 4

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warm air rises low pressure air cools cool air sinks high pressure at Earth’s surface wind cr eated 2 0 3 0 4 0 50 60 70 80 9 0 1 0 0 HUMIDITY -40 -40 -30 -20 -10 0 10 20 30 40 50 -20 0 20 40 60 80 100 120 60 70 80 90 100 140 160 180 200 © Copyright NewPath Learning. All Rights Reserved. 94-4408 www.newpathlearning.com Weather & Climate What makes weather? Images courtesy of NOAA, NASA. Air Pressure As air gets close to the Earth’s surface and warms up, the particles in the air move farther apart. The warm air then pushes down with less pressure and then rises forming an area of low pressure. Low air pressure results in a cloudy day. As air gets close to the Earth’s surface and cools, the particles in the air move extremely close together, this thick, cooler air sinks forming an area of high pressure. High air pressure results in clear skies. When air moves from an area of high pressure to a place with low pressure, wind is created. The Earth is surrounded by layers of air which make up our atmosphere. Weather is the outside conditions at a given time. Climate refers to the typical weather throughout the year in the same area. Many factors affect the weather such as the Sun, atmosphere, temperature, water, and air pressure. An air mass is a huge body of air that has practically the same temperature and humidity. The movement and interaction of air masses causes most weather conditions. A front is an area where two air masses meet. A warm front forms when a warm air mass bumps into a cold air mass that is not moving or is moving at a slow pace. Warm fronts usually move more slowly than cold fronts. Severe Weather A cold front forms when a cold air mass bumps into a warm air mass that is moving fast, not moving, or is moving at a slow pace. Measuring & Pr edicting Weather Meteorologists use weather maps and charts to record measurements and information about the weather happening in many areas. They use many tools to help them predict and record the weather each day. A thermometer measures air temperature. A hygrometer measures humidity. Humidity is the amount of water vapor in the air. A barometer measures air pressure. An anemometer measures the wind speed. A rain gauge measures the amount of rainfall. A hurricane is a storm that forms over oceans that bring winds reaching over 74 miles/119 kilometers per hour. A tornado is a funnel shaped column of air that touches the ground destroying anything in its path. It is smaller than a hurricane but has heavy winds. A drought is a long period of dry weather. A ood is a large overfl owing of water onto land that is normally dry. St or m y R ai n Cha nge Fa ir V er y D ry Warm Front warm air cold air cold air Cold Front warm air Weather Map Symbols High pressure Low pressure Warm front Cold front Stationary front
warm air rises low pressure air cools cool air sinks high pressure at Earth’s surface wind created © Copyright NewPath Learning. All Rights Reserved. 94-4408 www.newpathlearning.com Weather & Climate \xiBAHBDy01732lz[ Measuring and Predicting Weather Describe the following tools that meteorologists use to help them predict and record the weather each day: A thermometer ________________________________________________ A hygrometer __________________________________________________ A barometer ___________________________________________________ An anemometer ________________________________________________ A rain gauge ___________________________________________________ What makes weather? Severe Weather St or m y R ai n Cha nge Fa ir V er y D ry Photographs courtesy of NOAA, NASA. Air pressure How does air pressure effect weather? __________________________________ ___________________________________________________________________ What is humidity? ___________________________________________________ What is weather? ___________________________________________________ ___________________________________________________________________ What makes up Earth’s atmosphere? ___________________________________ ___________________________________________________________________ Describe the following severe weather conditions: A hurricane _____________________________ ________________________________________ A tornado ______________________________ ________________________________________ A drought ______________________________ ________________________________________ A flood ______________________________ _____________________________________ Key Vocabulary Terms air mass hurricane air pressure hygrometer anemometer rain gauge atmosphere temperature barometer thermometer climate tornado cold front warm front drought weather flood weather vane humidity What is air mass? __________________________________________________ _________________________________________________________________ What is a front? ____________________________________________________ _________________________________________________________________ Describe a warm front. ______________________________________________ _________________________________________________________________ Describe a cold front. _______________________________________________ _________________________________________________________________ -40 -40 -30 -20 -10 0 10 20 30 40 50 -20 0 20 40 60 80 100 120 60 70 80 90 100 140 160 180 200