Name Date. What Makes the Weather? There are four ingredients that go into making our weather. Air, sun, Earth, and water.

Transcription

1 Name Date Weather Study Guide What Makes the Weather? There are four ingredients that go into making our weather. Air, sun, Earth, and water. 1. AIR Barometer a. Air The Earth is surrounded by a huge ocean of air called our ATMOSPHERE. The atmosphere has layers. b. Air is made up of nitrogen, oxygen, water vapors, dust, pollen, ice crystals, and water droplets. c. Air expands (the molecules move faster and away from each other) when it is warm and contracts ( the molecules slow down and move closer to each other) when cold. d. Air has weight and pressure. We measure air pressure with a barometer. e. Air pressure is not the same everywhere because temperatures are different across the planet due to uneven heating of land and water. Layers of the Atmosphere

2 2. SUN a. The sun sends out energy in the form of radiation. We see this energy as light and feel it as heat. b. The sun s energy creates our weather. c. Some of the sun s energy is absorbed by our atmosphere some is reflected back into space and about half of the sun s energy is soaked into the earth and is radiated back into our atmosphere. We feel this as heat. d. Remember, it is not how close the Earth is to the sun that makes the surface warmer it is the angle of the planet to the sun that makes it warmer. e. We measure the sun s energy as heat through a thermometer. f. We use a dual-scale thermometer Fahrenheit (U.S. customary) and Celsius (Metric). g. Dark areas, like forests absorb more heat than light areas like snow covered lands which reflect heat. h. Oceans and other bodies of water hold heat longer than land.

3 3. Earth a. The Earth revolves around the Sun every 364 ¼ days. This is a year. b. The Earth spins or rotates on its imaginary axis every 24 hours. This is a day. c. The Earth s rotating and revolving cause our seasons. d. The Earth s surface heats differently because some places get more of the Sun s energy at different times of the year. This causes our weather.

4 4. WATER a. Water is in our air all the time even when you can t see or feel it. b. Water can be in the form of water vapor (gas), water droplets (liquid), and ice crystals (solid).

5 c. We call water vapor in the air humidity. d. The water cycle drives our weather. The water cycle is evaporation, condensation, and precipitation. e. Evaporated water doesn t always go into clouds it is in the air all around us. f. Water vapor needs something to condense on like dust or pollen to form precipitation. Precipitation can be in the form of rain, hail, snow, or sleet. g. We measure precipitation with a rain gauge. Air on the Move WINDS a. Moving air is called wind. b. Air always moves from an area of high pressure to an area of low pressure causing wind. c. If there is a big difference in two areas of air pressure there will be high winds. d. Some winds on our planet are in a pattern and happen over and over again. These are called prevailing winds. e. There are three main types of prevailing winds Trade Winds, Prevailing Westerly, and Polar Easterlies. f. The Earth s spin causes winds to blow in a certain direction this is called the Coriolis Effect. g. High volumes of air with similar temperature and pressure are

6 called an air mass. h. Air masses move and bring certain weather conditions with them. i. When two air masses meet it is called a front. There are cold fronts and warm fronts. When there is a front we have different weather like thunderstorms or blizzards. j. We measure wind speed with an anemometer. k. We measure wind direction with a wind vane. l. We can forecast our weather when we know the direction the wind is coming from. Mild and Wild Weather CLOUDS a. Clouds are made up of billions of tiny water droplets or ice crystals formed around tiny particles in the air. b. Clouds form when water evaporates from the surface of the Earth and then condense on specks of dirt, pollen, dust and other tiny particles in the air. c. Clouds are grouped and named by the way they look. d. Stratus (Latin for layers) clouds are the lowest clouds usually indicates precipitation. e. Cumulus ( Latin for pile) clouds look like big heaps of cotton piled up and are in the middle layer usually indicate fair

7 weather. f. Cirrus (Latin for curl) clouds are the highest clouds ice crystals that indicate a weather change. g. Precipitation falls from clouds. Rain is the most common form of precipitation. h. A cloud with the word nimbus in it always means rain. i. Lightening heats the air it expands quickly vibrates the air and cause thunder. Lightening always tries to find the shortest distance to Earth. j. Tornadoes are the most violent forms of all storms with winds over 200 mph. k. Hurricanes are the most damaging of storms. Most hurricanes in North America start in the Atlantic Ocean. l. Blizzards are snowstorms with strong winds - over 35 mph - and low visibility only ¼ mile. The Weather Watchers Weather Watchers of the Past a. Man has been forecasting weather for thousands of years. b. Until the last 100 years most weather was forecasted through human observation either looking at the skies or looking to animals for signs of weather changes. These types of forecasts were based on weather folklore. c. Meteorologists are scientists who study and forecast weather. d. Meteorologists work in many areas including the military,

8 e. f. g. h. i. j. k. sports, TV, radio, the space program, pilots, farmers, and many private industries. Thousands of people all over the world depend on weather forecasting or predicting for their safety from storms and floods, farming practices, recreation, shelter, travel, what to wear, how to protect their livestock, and much more. Today s meteorologists use many tools to help forecast the weather besides the weather instruments we have in our classroom. Weather balloons carry weather instruments and measure wind speed and direction, temperatures, humidity, and air pressure at different altitudes in our atmosphere. Weather satellites are small space crafts that fly above our atmosphere and send back information about cloud cover, air and ocean temperatures, storms, fronts, and global weather patterns. Radar (RAdar Detection And Range) stations, such as Doppler radar, are positioned all over the planet and use radio waves to show precipitation. Computers can take all the data collected by all the weather instruments and tools and very quickly (millions of operations per second) build weather models and maps that help meteorologists forecast. Meteorologists use symbols to represent different weather information and display them on maps. Remember the difference between climate and weather! Weather - The state of the atmosphere at a given time and place. Climate - The meteorological conditions, including temperature, precipitation, and wind, that characteristically prevail in a particular region