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DISCOVERY FILE |
Hurricane winds blow hard. In fact, they have to blow at least 74 miles an hour or a storm isn't even called a hurricane!
But once a storm has enough wind speed to be called a hurricane, that's not the end of the story. One day it might be blowing 100 miles an hour and the next day 80. Then three days later it might be blowing 120.
Why all the changes? What might cloud temperature have to do with the changing speeds? And why might land cause the winds to speed up or slow down?
In Hurricane Activity #2 you will investigate the relationships among these variables, but why might someone think that such a relationship exists?
Perhaps it's because hurricanes are powered by tropical waters. Air rises when it is heated by warm surface waters near the Equator. The hotter the water, the more the air rises and the faster the winds blow. And, the more the air rises, the colder it becomes. In fact, for every 300 m of rise, its temperature falls 3o Fahrenheit.
Can you think of a reason that land might have an effect on hurricane wind speed?
For more information on hurricane formation, read the Discovery file on page 19 of Hurricane! the Event-Based Science book on weather.