4 A SWIRLING MYSTERY The world around us contains many amazing and mysteri ous features One such phenomenon is called a whirlpool Whirlpools are water that moves very quickly in a circle They can be found anywhere in Earth’s oceans rivers and lakes They can be any size Tiny whirlpools can be found in your home when water drains from your sink or bathtub Hundreds of years ago sailors wondered if whirlpools could be giant undersea monsters or gates to another world Today we know that Several different forces can cause water to swirl and form a whirlpool
5 whirlpools are not as mysterious as they seem and that they can be explained with science A combination of natural forces that exist in our world can cause whirlpools to form Situations created by nature or accidentally by humans may set off forces that result in whirl pools These situations can include ocean tides sinkholes or tsunamis Though scientists can now explain what whirl pools are and why they exist scientists continue to wonder at how beautiful and violently dangerous they can be A tsunami is a very high large wave in the ocean that is usually caused by an earthquake under the sea and that can cause great destruction when it reaches land VOCABULARY Some sinkholes such as the one seen here occur naturally Others are the result of human actions
6 If you fill a bathtub or sink with water and then pull the drain a whirlpool will form as water goes down the drain The water will swirl in a circular motion The diameter or measurement across the cen ter of the circle is wider at the top and narrows as the water moves down The funnel-shaped swirling mass of water called a vortex will pull any floating objects around it into its center A vortex can also be Water swirling down a drain can move in either a clockwise or counterclockwise direction VISUALIZING A VORTEX
7 How are tornados and whirlpools similar How are they different COMPARE AND CONTRAST the swirling mass of air in a tornado This is why a whirlpool looks very much like a tornado Whirlpools can form in many different sizes Some may have a diameter of only a few inches Others can be more than 30 feet 9 meters across One of the largest known whirlpools measures more than 250 feet 76 meters in diameter That is about as long as a soccer field In large whirlpools the water can rush through the vortex at great speeds The rushing water can make loud roaring noises that can be heard from far away Here a whirlpool occurs off the coast of the Canary Islands in the Atlantic Ocean
