MAPPING THE WEATHER. Introduction. Time Needed. What You Need. Safety Precautions

Transcription

1 MAPPING THE WEATHER Introduction Weather maps are used by meteorologists to view different elements of the weather over a large area of the Earth s surface. A weather map can be made by plotting on a geographical map several values such as pressure, temperature, precipitation, and cloud cover. Weather maps show symbols to represent the different values. Meteorologists organize weather maps by drawing curved lines called isobars and isotherms. These lines connect places on the map with equal values. Isotherms are lines that connect points of equal temperature. The spacing between isotherm lines indicates a temperature gradient, the amount of temperature change over a given distance. Isobars are lines that connect points of equal atmospheric pressure, so they can be used to define high- and low- pressure regions. In this experiment, you will create weather maps of current global conditions. Time Needed 55 minutes What You Need access to the Internet and a computer with a printer colored pencils science notebook Safety Precautions Please review and follow the safety guidelines.

2 MAPPING THE WEATHER 2 What You Do 1. Using the Internet, go to the Web address 2. On the top menu bar, click on surface. 3. Under the surface heading, select the following maps and print them: pressures, temperatures, and 24-hour precipitation. 4. Under the cloud cover heading, select radar. Select the radar map and print it. These maps are updated for each current day. 5. On the pressure map (see Figure 1), notice the numbers that indicate air pressure. They are written in units called millibars. The line connecting two points of equal pressure is called an isobar. This means that all of the points along an isobar have the same air pressure. Isobars are usually drawn for increments of 4 millibars. Maps will show isobars for all of the places where air pressure is millibars, 996 millibars, 992 millibars, and so on. On the map, find all the locations where the air pressure is the same. Connect these locations with lines. Seattle San Jose Los Angeles Denver El Paso 996 L Chicago 996 Memphis Houston New York Jacksonville Figure 1 6. On the surface temperature map (Figure 2), use a red pencil to draw isotherms, lines connecting points of the same temperature. Start with the lowest temperature. Draw isotherms for every 10 F above the lowest temperature.

3 MAPPING THE WEATHER Figure 2 7. Compare your completed maps with maps on the Website that already have isotherms and isobars drawn on them. These maps are located under the following titles: pressures and temperatures. 8. Refer to the USAToday.com Website ( and select weather from the menu bar on the left hand side. Observe the radar, precipitation, temperature, and satellite maps for the current day. Observations 1. What patterns on your temperature map do you see for the different temperatures in the United States? 2. Is there a connection between temperature and air pressure based on the maps you have observed? If so, what is it?

4 MAPPING THE WEATHER 4 3. Can you determine a difference between the areas of precipitation on the precipitation map and the radar map? 4. Latitude is largely responsible for varying temperatures. Why do you think that different temperature regions are circular and wavy, not just straight lines? Want to Know More? See Our Findings.

5 SAFETY PRECAUTIONS Review Before Starting Any Experiment GENERAL Always obtain your teacher s permission for experiments performed at school, and your parent s permission for experiments performed at home, before attempting any experiment. Read all instructions for an experiment before starting the experiment, and follow the directions exactly as they appear in this volume. If an experiment requires adult supervision, do not perform the experiment unless you have an adult supervising you the entire time you are performing the experiment. Wash your hands before the start of and after each experiment you perform. Keep your work area clean. Never eat or drink while performing an experiment. Never taste a substance used in an experiment unless you are told that it is safe to do so. Be aware of the location of safety equipment you may need in an emergency, such as running water, an eyewash if you are at school, and a fire extinguisher. If you are going outside, make sure you have permission to go from your teacher and parent. Take a buddy with you, and dress appropriately for the weather. Make sure you or someone who accompanies you is familiar with the area, and bring along a firstaid kit in case of emergency. Never look directly into the Sun. CHEMICAL SAFETY Always wear goggles when working with chemicals, such as acids and bases, and near heat sources like flames. If at all possible, avoid wearing contact lenses when working with chemicals. If any substance gets into your eyes, notify an adult (e.g., your teacher or parent) immediately, and flush your eyes with running

6 SAFETY PRECAUTIONS 2 water for at least 15 minutes. Do not mix chemicals unless you are told to do so by a teacher or parent. Never touch, taste, or smell chemicals unless instructed to do so. Keep chemicals in closed containers when they are not in use. Dispose of all chemicals properly. Do not pour any chemicals or solids down the drain unless instructed to do so. Use safety gloves and a plastic apron when handling chemicals. If any chemicals spill on your skin, rinse the affected area with running water for at least 10 minutes, and notify your teacher or parent immediately. Take precautions to avoid spilling chemicals. If a chemical spills on any surface, notify your teacher or parent immediately to assist with clean-up. Exercise caution when using sharp instruments such as knives or scissors. Always cut away from yourself, not toward yourself. If you cut yourself, notify your teacher or parent immediately. GLASSWARE Clean glassware when you are finished with the experiment. Be careful when using glassware. If a piece of glassware breaks, have an adult assist you in clean-up to avoid injuries from broken glass. Never use broken or damaged glassware. FIRE SAFETY Do not heat glassware that is not completely dry. Do not pick up hot glassware without heat-resistant gloves or tongs. When heating glassware, keep it away from yourself and from others. Do not heat anything unless instructed to do so by a teacher or parent. Do not heat substances in a closed container. After an experiment, make sure that all heating sources are off and that all flames have been put out.

7 SAFETY PRECAUTIONS 3 Do not reach across such heating sources as flames. If you have long hair, tie it back, out of the way. Do not wear clothing with loose sleeves, scarves, bows, ties, or anything else that may hang into a fire. Do not wear long earrings. ELECTRICAL SAFETY Do not touch electrical equipment when your hands are wet. Do not plug several electrical devices into one outlet or use an extension cord.