WebGuide An Internet based lesson A lesson built around a single Internet Site

Subject: Earth Science or Math
Lesson Title: "Watch out radar! Here comes a speeder!"
Internet Site Title: United States RadarLoop by Intellicast.com
Alternate site: http://www.intellicast.com/LocalWeather/World/UnitedStates/JavaLoop/ (Use this site for more control over the speed of the images, or for the ability to step forward one image at a time)
Author: Bill Byles

Site Description: This site as a loop of seven images which cover a span of six hours. Each time the image changes, an hour has passed. When you first get to the site you will have to scroll down so you can see the entire contiguous US map. Notice the top left corner of the map has the time and date in GMT (Greenwich Mean Time). Each time that the image changes you will see the time increase one hour. During months during which Daylight Saving Time is in effect, the Central time zone is five hours earlier on a clock (six during Standard Time). Colors are explained on the bottom left corner of the map. You will occasionally see weather events develop and spread across an area. Usually you will be able to see some line of weather that moves across an area during the six hour time span. If you are unable to find interesting weather features, look at some of the sample loops below.

Site Purpose: You are looking for a weather pattern that moves across the map. Most movement will be from west to east. Watch several loops of the map until you can locate some line of clouds that moves across an area. Look for areas with yellow or red. Mark a clear starting point for that line and a clear finish point. If the event breaks up or stops before the entire six hours pass, use only a portion of the six hour span. Count the number of times the image shifts. That will be how many hours pass. Your starting and finish points will allow you to calculate distance. Knowing what distance an object moved in what time period will allow you to calculate the speed of the object.

Lesson Introduction: You will work in groups of three. Someone in your group should have an outline map of the US before going to this site.

Final Product or Task: You will use an Excel spreadsheet, or pocket calculator, to calculate the speed with which a line of thunderstorms moved across a given state. Your results and to be reported with a one-page Word document on which you have inserted an image from the Internet. Your group will present a report of the area you chose to the class, using the saved image of your radar loop. Make a prediction where the weather feature you were watching will be in six hours, and defend your prediction to the class.

Lesson Description: Open the US Radar Loop site using the URL given above. Assign a different portion of the map on your computer screen to each group member. Watch several loops of the Doppler Radar map until you identify a place where a clear pattern emerges. If more than one looks promising, your group should come to an agreement about which one will be used. Mark the map while watching the film loop. Do not trust memory to mark the map later. Also make a notation of the colors involved in the line of weather that you were watching. Save the image of the loop you are watching. This can not be saved to a disk, it is too large. Save the file to the shared folder, remember to rename the film loop. When your group has marked the two map points, move to the center where larger maps are located.

As exactly as possible, determine the number of miles between the starting and finish points. Use the smaller map to pinpoint two spots on a larger map. Measure the number of centimeters (to the nearest tenth) between the two map points. Using the scale of the map, determine distance between the two points. As an example; if one centimeter equals 20 miles, a distance of 15 centimeters on the map is equal to 300 miles.

Calculate the speed of the line of weather.

Move back to a computer and report the results of your calculations. Include the part of the country where this happened, report the speed of the weather and indicate how severe the weather was (remember the colors?). Make a prediction as to where the line will be in six more hours. Include an image with your report. Be sure all three group members names are on the report, then save it to the shared folder for evaluation.