Kids' Korner

THE SCIENCE OF WEATHER: HURRICANES

2010-06-02T15:37:00.008-04:00

We’ve learned about various forms of weather, everything from blizzards to tornadoes. Now let’s take a look at one of its most extreme manifestations, the tropical cyclone, or a hurricane, as it’s most commonly called. It’s hurricanes that can wreak havoc on lives with the floods, tornados and wind damage that ensue during and after the storm. So lets find out a little more about hurricanes.

What exactly is a hurricane?

A hurricane is a huge storm that can span 600 miles across and have strong winds ranging from 74-200 miles per hour (mph). The storms are usually a weeklong and form in the southern Atlantic Ocean, Caribbean Sea, Gulf of Mexico, and in the eastern Pacific Ocean. They move 10-20 mph over the open ocean. With them, these storms usually bring rain, thunder and lightening. Once on land, the heavy rain, strong winds and large waves can have a damaging affect on buildings, cars, and trees. Not to mention the devastating impact hurricanes leave on people.

How do hurricanes form?

Hurricanes form over ocean water of 80°F or warmer and it’s from these warm ocean waters that hurricanes gather their heat and energy. They also require the influence of the Earth’s rotation to initiate a spinning circulation called the Coriolis Effect. Evaporation from the seawater increases their power. Once formed, a hurricane rotates in a counter-clockwise direction around an “eye.” As the center of the hurricane, the “eye” is the calmest part, with only light winds and fair weather.

What’s the difference between a typhoon and a hurricane?

Typhoons and hurricanes are essentially the same thing, a strong tropical cyclone. The difference, however, lies in where they form. For example, a tropical cyclone that originates in the North Pacific Ocean west of the International Dateline is known as a typhoon. Yet a tropical cyclone that forms in the North Atlantic and Northeast Pacific Oceans east of the International Dateline or South Pacific Ocean east of 160E is considered a hurricane.

What’s the International Dateline? Well, it’s an imaginary line set approximately along the 180^th meridian designated as the place where each calendar day begins. Click here to find out about this interesting time line!

When is hurricane season?

The Atlantic hurricane season runs from June 1 to November 30. But don’t be too fast to rule out all the other months, as hurricanes have occurred outside this six-month window. What this does mean is that the months that make up hurricane season include over 97 percent of tropical activity. For decades, June 1st has been the official kick off for the Atlantic hurricane season, however, the same can’t be said for November 30th as the end date. Hurricane season’s designated end date has shifted from October 31st to November 15th until the current date of November 30th.

The season does seem to peak from August through October. In fact, 78 percent of the tropical storm days, 87 percent of the minor (Categories 1-2) hurricane days, and 96 percent of the major (Categories 3-5) hurricane days occur during this time. Yet, maximum activity occurs in early to mid September. (Hurricane Research Division)

How are hurricanes ranked?

The United States utilizes the Saffir-Simpson hurricane intensity scale to rank Atlantic hurricanes. This scale gives an estimate of the potential flooding and damage to property given a hurricane’s estimated intensity. Take a look at the list below to see hurricane categories and some examples.

Category 1: 74-95 MPH wind, Hurricane Earl (1998), minimal damage
Category 2: 96-110 MPH wind, Hurricane Georges (1998), moderate damage
Category 3: 111-130 MPH wind, Hurricane Fran (1998), extensive damage
Category 4: 131-155 MPH wind, Hurricane Hazel (1954), extreme damage
Category 5: 155+ MPH wind, Hurricane Camille (1969), catastrophic damage

How do I know that a hurricane is headed my way?

Well, look out for two key terms on radio and television, hurricane watch and hurricane warning. If you keep your ear open for these two words than you will know if a hurricane is on track for your area.

More specifically, when the forecast calls for a Hurricane Watch, it means a hurricane is possible within 36 hours. In this case, stick close to the radio and TV so you’ll know the latest information. Be assured that the Hurricane Center is tracking the storm and trying to predict where the storm may come ashore.

However, if you hear the words Hurricane Warning, then a hurricane is expected within 24 hours. In this case, you may be told to evacuate. This is the time that you and your family should discuss preparations, such as getting grocery supplies, gassing up vehicles, boarding windows, and/or making plans for pets in the event you have to leave.

Why do hurricanes have names?

Well why does anything have a name? Think of how hard it would be to communicate with others if you didn’t use names. Hurricanes are no different, that’s why all of them have names. Naming the hurricanes is essential to establishing good communication between the public and the meteorologists who watch the storms; making it easier for them to alert you about forecasts, watches, and warning. Hurricanes can often last a week or longer, and there can be more than one at a time. Without names it would be pretty confusing to decipher which storm is being described.

The actual naming of hurricanes has an interesting history. In the early 20th century an Australian forecaster assigned the first proper name of a tropical cyclone, using politicians he disliked as a naming source. Then during World War II, hurricanes were informally given female names by the US Army Corp and Navy meteorologists who were monitoring tropical cyclones over the Pacific. However, from 1950 to 1952 tropical cyclones occurring in the North Atlantic Ocean were named using the phonetic alphabet. Then in 1953 the US Weather Bureau (now known as the National Weather Service) began using female names for storms. In 1979, the World Meteorological Organization (WMO) and the NWS switched practices to include the use of both male and female names for tropical cyclones.

The WMO uses the names on six lists, where each name corresponds to a letter of the alphabet. But, if you look at the lists you’ll see that the letters: Q, U, X, Y, and Z were excluded from the lists due to the lack of names beginning with those letters. The lists are reused every six years. Some hurricane names are retired if the storm has been very deadly or costly; in that case the WMO adds a new name to the list.

Construct your own virtual hurricane here!

Sources:

NOAA

FEMA For Kids

SC State Climatology Office

National Hurricane Center

Weather Whiz Kids

THE SCIENCE OF WEATHER: TORNADOES

2010-04-21T11:38:00.005-04:00

Photo Credit: Sean Waugh NOAA/NSSL

From “Twister” to “The Wizard of Oz,” there have been many movies that feature the whirling tornado. But how much do we know about this fast and furious force of nature? Join in as we discover the ins and outs of the tornado.

Tornadoes are born out of a powerful thunderstorm (a storm with thunder and lightening), called a supercell. A supercell can last longer than a normal thunderstorm. The same trait that’s responsible for the storm’s longer duration also creates most tornadoes. Wind coming into the storm starts to swirl and forms a funnel. The air inside the funnel spins so fast it pulls in more air—and objects. The funnel begins to act like a vacuum cleaner, sucking up everything in its path.

Click here to see how tornadoes form!

Tornadoes occur most frequently in the United States, with an average of 800 reported each year. They require an unstable atmosphere and form where cold dry polar air meets warm moist tropical air. This occurs most often in the Great Plains of the United States, which is why it’s called Tornado Alley. Tornadoes come in all shapes and sizes, and can happen at any time. It’s their quick formation that can make them especially dangerous.

Did you know. . .?

Tornadoes are rated on a scale of 0 to 5.
Tornadoes can be deadly. Some can have winds over 300 miles an hour—that’s enough to lift houses off the ground and bark off the trees!
Tornadoes can damage an area one mile wide and 50 miles long.
While tornadoes can happen at any time of the year, they typically occur from March-August.
The air pressure is very low inside the funnel, just like pressure is low inside the eye of a hurricane. Only in a tornado, the pressure is a lot lower—lower than any other place on earth.

Important Terms To Know:

Tornado Watch—Tornadoes are possible. Stay tuned to the radio or television news.

Tornado Warning—A tornado has been sighted. Take shelter immediately!

Now that you know a little more about tornadoes, go make one in a jar. Click to find out how!

Sources

http://www.windows.ucar.edu/

http://www.fema.gov/kids/tornado.htm

http://www.weatherwizkids.com/weather-tornado.htm

http://www.nationalgeographic.com/xpeditions/lessons/15/gk2/tornadowhat.html

The Science of Weather

2010-02-16T13:29:00.018-05:00

We experience weather everyday, but do we really know what it means? In its basic sense, weather is the state of the atmosphere at any given time with respect to wind, temperature, cloudiness, moisture and pressure. Floods, thunderstorms and hurricanes are a few extreme manifestations of weather. Do you know any more? Click here to learn about other weather related terms.

Weather plays an important role in our daily lives. One of the first things many of us do in the morning is check the weather. Some may search the newspaper or television for the day’s forecast, while others may make observations by peaking out doors or windows. Why do we do this? Well, weather determines what we wear, what we do and where we go. More importantly, knowing what to do in the case of extreme weather can save our lives. That’s why meteorology is so important. By definition, meteorology is a type of science that deals with atmosphere and its phenomena, especially with weather and its forecasting. Generally, the person you see on the news delivering the weather forecast is a meteorologist. There are many other career options in the field of meteorology, such as a climatologist or a radar meteorologist. In addition, a career in meteorology could lead to job opportunities at NASA, the National Weather Service or the military.

Now that we know a little more about weather, lets talk about some of its extremes. From blizzards and hurricanes to droughts and tornados, the world of weather is dynamic. In the months to come we’ll tackle each of these weather extremes. Lets kick off with blizzards.

Blizzards

The majority of us have seen snow at some point in time. You know the white stuff that falls from the sky when it’s cold outside. Whether you’ve felt its icy touch or seen it on TV, you have a general idea of what snow is. What about blizzards? They involve snow, but depending on where you live you may not have experienced one. So lets find out more about these winter storms.

Standing tall on North Dakota snow A March blizzard nearly buried utility poles. Caption jokingly read "I believe there is a train under here somewhere!"   (1966)

Credit: Collection of Dr. Herbert Kroehl, NGDC

Blizzards are severe winter storms that bring high winds and blowing snow, which makes for low visibility. According to the National Weather Service, a blizzard is a storm with winds 35 miles per hour (mph) or greater and heavy snowfall and/or blowing snow that reduces visibility for less than ¼ mile for three hours are longer. A severe blizzard has temperatures nearing 10°F or below with winds greater than 45 mph and snowfall that reduces visibility to near zero. Heavy snowfall and low temperatures usually accompany blizzards, but are not necessary for them to occur. Ground blizzards can form when strong winds pick up snow that has already fallen.

Red Cross workers search for victims buried in cars following snowfall during the Blizzard of "77." Only about 12 inches of new snow fell during this event but high winds coupled with existing snow in western New York and accumulated snow on the surface of frozen Lake Erie combined to cause major difficulties.   (Feb 1977)

Credit: American Red Cross

How do they form?

You need three things for a blizzard to form: cold air, moisture, and lift. See below for the blizzard recipe.

Cold air (below freezing) for snow: It’s a funny thing; snow won’t fall to the ground unless it’s cold. It needs to be cold both up in the clouds for snowflakes to form and down at ground level for snow to stick.
Moisture to form clouds and precipitation: Moisture in the air is called water vapor. Generally blizzards form near some body of water. That’s why air that blowing across a large lake or ocean is an excellent source of water vapor. As wind moves air over the water, some water evaporates from the surface, leaving vapor in the air.
Warm, rising air is needed to form clouds and cause precipitation: The formation of a blizzard is due to warm air rising over cold air. So, how can this happen? In one of two ways. Winds can pull cold water toward the equator from the poles and bring warm air toward the poles from the equator. When warm air and cold air are brought together, a front is formed and precipitation occurs. Warm air can also rise to form clouds and blizzard snows as it flows up a mountainside.

Where do most blizzards occur?

Blizzards occur at a higher frequency in the upper Midwest and Great Plains of the United States. However, blizzards can occur in any location that has a climate that experiences snowfall.

The Great Blizzard of March 12, 1888.  

Credit: National Oceanic and Atmospheric Administration/Department of Commerce

What to look out for during a blizzard?

Hazardous driving conditions
Very low wind chills. Exposure to low wind chills could lead to frostbite or hypothermia.
Power outages
Frozen pipes
Low fuel supply

Sources:
National Weather Service-Flagstaff

weather.com

Web Weather for Kids

weatherwizkids.com

Holiday Science

2009-12-18T13:37:00.001-05:00

School’s out for the holidays, so lets have some science fun! Anyone want to make some crystals? Follow these steps and you can have a beautiful crystal decoration that would make a great gift, or maybe an ornament for the Christmas tree.

You will need help from an adult for this experiment.

Here's what you'll need:

Borax powder (NOT Boraxo)
Pipe Cleaners
Measuring Cup
Measuring Spoon
Pot
Wide-mouthed jar (pint or quart)
String
Scissors
Food Coloring (optional)

Here’s what you’ll do:

Get creative and use your pipe cleaners to make a shape. It can be a circle, heart, snowflake, or anything you wish. Make sure that the shape isn’t too big, it has to hang inside your jar!

Take the string and tie a few inches of it to one of the pipe cleaners. Cut the string and tie the remaining end to the pencil, make sure it’s enough string so the object can dangle inside the jar.

Measure how many cups of water it would take to fill the jar so that it covers your hanging object, then have your parents or an adult pour that water into a pot to boil. Don’t use a microwave to boil the water!

Have your parents or an adult pour the boiled water into the jar.

Slowly stir in the Borax, 3 tablespoons per cup of water, and if you want, you can add some food coloring too!

Now place your pipe cleaner artwork into the Borax solution, without touching the sides or bottom of the jar, and support it by hanging it from a pencil placed over the mouth of the jar.

The next day you should have a beautiful crystal decoration. Take it out and let it air-dry.

Archaeology: Can You Dig it?

2009-06-04T09:34:00.000-04:00

Like playing in the dirt? Well join ScienceSouth for ScienceSaturday, where this month's theme is Archaeology: Can You Dig It? Become an archaeologist for a day and "unearth" the mysteries of a lost city! Uncover artifacts, learn about past cultures, and test your detective skills as we discover how people lived long ago.

When: June 6, 2009 from 9 am-noon

Where: ScienceSouth Pavilion at Freedom Florence

1511 Freedom Blvd.

Florence, SC 29505

Cost: $15.00/child

Ages: 5-12

Homeschool Friday

2009-06-03T13:34:00.000-04:00

Hey Kids! This Friday (June 5th) is the last Homeschool Friday for the school year. The topic is Robotics/Vehicles. How cool is that? If you're interested let your parents know. They can call 843-679-5353 or register at www.sciencesouth.org. The cost is $5.00/child and is for students in grades K-8th.

While this school year is coming to a close, look out for Homeschool Academy for the 09-10 school year. In addition to K-8th workshops, ScienceSouth will also begin high school workshops in biology and chemistry. Parents can call 843-679-5353 for additional information.

Hope to see you soon!