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Wednesday, March 12, 2008

Your Amazing Brain



Different parts of the brain control different functions.
Illustration by Robert J. Demarest


You carry around a three-pound mass of wrinkly material in your head that controls every single thing you will ever do. From enabling you to think, learn, create, and feel emotions to controlling every blink, breath, and heartbeat—this fantastic control center is your brain. It is a structure so amazing that a famous scientist once called it "the most complex thing we have yet discovered in our universe."

Your brain is faster and more powerful than a supercomputer.

Your kitten is on the kitchen counter. She's about to step onto a hot stove. You have only seconds to act. Accessing the signals coming from your eyes, your brain quickly calculates when, where, and at what speed you will need to dive to intercept her. Then it orders your muscles to do so. Your timing is perfect and she's safe. No computer can come close to your brain's awesome ability to download, process, and react to the flood of information coming from your eyes, ears, and other sensory organs.


Your brain generates enough electricity to power a lightbulb.

Your brain contains about 100 billion microscopic cells called neurons—so many it would take you over 3,000 years to count them all. Whenever you dream, laugh, think, see, or move, it’s because tiny chemical and electrical signals are racing between these neurons along billions of tiny neuron highways. Believe it or not, the activity in your brain never stops. Countless messages zip around inside it every second like a supercharged pinball machine. Your neurons create and send more messages than all the phones in the entire world. And while a single neuron generates only a tiny amount of electricity, all your neurons together can generate enough electricity to power a low-wattage bulb.

Neurons send information to your brain at more than 150 miles (241 kilometers) per hour.

A bee lands on your bare foot. Sensory neurons in your skin relay this information to your spinal cord and brain at a speed of more than 150 miles (241 kilometers) per hour. Your brain then uses motor neurons to transmit the message back through your spinal cord to your foot to shake the bee off quickly. Motor neurons can relay this information at more than 200 miles (322 kilometers) per hour.
When you learn, you change the structure of your brain.

Riding a bike seems impossible at first. But soon you master it. How? As you practice, your brain sends "bike riding" messages along certain pathways of neurons over and over, forming new connections. In fact, the structure of your brain changes every time you learn, as well as whenever you have a new thought or memory.

Exercise helps make you smarter.

It is well known that any exercise that makes your heart beat faster, like running or playing basketball, is great for your body and can even help improve your mood. But scientists have recently learned that for a period of time after you've exercised, your body produces a chemical that makes your brain more receptive to learning. So if you're stuck on a homework problem, go out and play a game of soccer, then try the problem again. You just might discover that you're able to solve it.

Dino Death Pit!


Text by Elisabeth Deffner
Two toothless meat-eaters called Ceratosaurs battle for dominance.
Image by 422 Limited/National Geographic Television Art and Animation


Nearly 100 million years before giant dinos like Tyrannosaurus rex ruled the world, a volcano rumbled in an ancient, marshy land. Fiery lava belched out of the crater, and ash snowed down on what is now part of the Gobi desert in China.

As it fell onto the moist earth, the ash combined with water to create a gooey mud trap, like superthick quicksand. Before long, a small dinosaur called a ceratosaur wandered into the muck on its hind legs and couldn't break free. Another meat-eating dino spied easy prey and ran toward the helpless animal. But this was no free lunch! Both predator and prey sank to their doom in the "quickmud."

This scene may have played out again and again as at least 14 dinosaurs tumbled into three different mud traps. Now, more than 160 million years later, scientists have unearthed this dino graveyard—including fossils of the oldest known member of the tyrannosaur family. And the discovery is revealing ancient secrets from the age of the dinosaurs.

Lost in Time

Fossils have shown that the earliest dinosaurs lived about 230 million years ago and were only about the size of today’s German shepherds. About 145 million years ago, massive dinos such as the four-story-tall Brachiosaurus began to stomp the Earth. But what did dinosaurs look like in between?

"The mud pits are a real discovery," says dino expert James Clark, who participated in the dig. "There are very few dinosaur fossils from this time in the middle, when the animals started transitioning into giants."

Dinosaur Pancakes

As scientists chipped away at the remains of the mud pits—now giant blocks of rock they found one unusual creature after another. "They were stacked up like pancakes," Clark says.

Among other fossils, they uncovered a bizarre toothless meat-eater called a ceratosaur; an ancestor of the horned dinosaurs—such as Triceratops—named Yinlong; as well as ancient turtles, mammals, and crocodiles.

But the most incredible discovery of all is a new two-legged predator with a Mohawk-like crest on its head. Named Guanlong, Chinese for "crested dragon," it weighed just 165 pounds (74.8 kilograms). But parts of the animal's skull and a telltale ridge in its hip bone look strikingly similar to gigantic tyrannosaurs that lived about 100 million years later—including the 15,000-pound (6803.8-kilogram) Tyrannosaurus rex.

Digging Up Answers

Now these discoveries are helping to solve many dinosaur mysteries. You probably know that Tyrannosaurus rex had surprisingly wimpy arms and used its terrifying teeth to grab prey. But did its ancestors have more powerful arms? Yes. Guanlong's muscular limbs show that early tyrannosaurs probably snatched prey with their arms.

Ferocious Triceratops fought off enemies with its three dangerous horns and a bony frill around its neck. Did the beast's smaller ancestors have horns, too? No. "Yinlong may not have needed big horns because it was smaller and could probably flee from predators more easily," says National Geographic's dino expert Josh Smith.

And these finds are just the beginning. As the dig continues, the strange creatures of the Gobi death pits could help scientists rewrite the history of dinosaurs.

Cow Power


Text by Catherine Clarke Fox
One cow can create an incredible 30 gallons (114 liters) of manure each day.
Photograph by James P. Blair

When the Audet family turns on the lights at Blue Spruce Farm in Bridport, Vermont, they are using electricity that comes from cows—cow manure, to be specific.

Cows produce a lot of manure. One cow can create an incredible 30 gallons (114 liters) of manure each day. Now imagine the output of over 1000 cows at Blue Spruce Farm. That’s one big pile of cow pies.

When farmers clean their barns, they put the manure in a big heap, and spread some of the stinky stuff on their fields for fertilizer.

But now places like Blue Spruce Farm have a new way of handling cow manure. They use it to make electricity.

Here's how it works: A big pooper scooper that looks like a squeegee moves back and forth cleaning the barn floor. The cows aren't bothered, says Marie Audet. "They are creatures of habit; they get used to it, and just lift one foot and then another to let it go by."

The scooper pushes the manure into a big 600-gallon (2,268 liters) concrete tank like a swimming pool. The tank is called a digester because what happens there is just like what happens inside a cow: Bacteria get to work and continue to digest the manure.

Methane gas in the atmosphere is known as a "greenhouse" gas because it traps heat just like a greenhouse does, causing our planet to warm up. That's an environmental concern. But the digester process has a positive outcome. The gas is captured and used as fuel to power electric generators.
At Blue Spruce Farm, the generators make enough electricity to power 400 homes. The Audet family sells the extra electricity they can't use themselves.

Manure that has been in the digester for three weeks gets pushed out to make room for the next batch. Then a machine squishes the liquid out of it.

"The liquid is used to fertilize the fields, and it doesn't smell at all," says Mrs. Audet. And, while it might sound unusual, the dried solids make fluffy, odor-free bedding for the cows.

"We used to have to buy a tractor-trailer load of sawdust every week for cow bedding," says Mrs. Audet. That's $1,200 they don't have to spend any more.

Tuesday, March 11, 2008

Harriet Tubman: Civil War Spy




Tubman was often called Moses, after a Biblical hero who led his people out of slavery in Egypt.
Photograph by James A. Gensheimer
Text by Catherine Clarke Fox
Harriet Tubman is well known for risking her life as a “conductor” in the Underground Railroad, which led escaped slaves to freedom in the North. But did you know that the former slave also served as a spy for the Union during the Civil War and was the first woman in American history to lead a military expedition?

During a time when women were usually restricted to traditional roles like cooking and nursing, she did her share of those jobs. But she also worked side-by-side with men, says writer Tom Allen, who tells her exciting story in the National Geographic book, Harriet Tubman, Secret Agent.

Tubman decided to help the Union Army because she wanted freedom for all of the people who were forced into slavery, not just the few she could help by herself. And she convinced many other brave African Americans to join her as spies, even at the risk of being hanged if they were caught.

In one of her most dramatic and dangerous roles, Tubman helped Colonel James Montgomery plan a raid to free slaves from plantations along the Combahee (pronounced “KUM-bee”) River in South Carolina. Early on the morning of June 1, 1863, three gunboats carrying several hundred male soldiers along with Harriet Tubman set out on their mission.

Tubman had gathered key information from her scouts about the Confederate positions. She knew where they were hiding along the shore. She also found out where they had placed torpedoes, or barrels filled with gunpowder, in the water.

As the early morning fog lifted on some of the South’s most important rice plantations, the Union expedition hit hard. The raiders set fire to buildings and destroyed bridges, so they couldn’t be used by the Confederate Army. They also freed about 750 slaves—men, women, children, and babies—and did not lose one soldier in the attack.

Allen, who writes about this adventure and many others, got to know Tubman well through the months of research he did for the book. The historic details he shares bring Tubman and many other important figures of her time to life.

To gather the facts, Allen searched libraries and the Internet, and even walked in Tubman’s footsteps. “I went on the river just south of the area where the raid took place,” he says. “You are in that kind of country she would have known, with plenty of mosquitoes and snakes, and there are still dirt roads there today—so you get a feeling of what it was like.”

Allen says his most exciting moment came when a librarian led him to written accounts by people who actually saw Tubman and the raiders in action.

“She was five feet two inches (157 centimeters) tall, born a slave, had a debilitating illness, and was unable to read or write. Yet here was this tough woman who could take charge and lead men. Put all that together and you get Harriet Tubman. I got to like her pretty quickly because of her strength and her spirit,” Allen says.

To find out more about this courageous and adventuresome woman, read the book, Harriet Tubman, Secret Agent.

Slow Down for Calvin the Right Whale!


Another view of Calvin with head scars.
Courtesy New England Aquarium
In 1992, the mother of a North Atlantic right whale (Eubalaena glacialis) was hit and killed by a ship in Canada’s Bay of Fundy. Researchers studying these whales named the 8-month-old baby Calvin because they knew that in order for it to survive, it would need to be feisty, like the character in the cartoon strip Calvin and Hobbes.

A proposed government rule would require ships to slow down in areas where right whales are known to swim. “Our data suggest that whales hear ships but not in time to get out of the way,” says Amy Knowlton, a research scientist with the New England Aquarium. “This rule will help so much. Even a few seconds can make a huge difference.”

It isn’t easy to move out of the way fast when you are bigger than a school bus. Adult right whales can be 40 to 50 feet (12 to15 meters) long and weigh 200,000 pounds (90,000 kilograms). Babies, called calves, are never tiny. They are born weighing about 2,000 pounds (900 kilograms) and are about 13 feet (4 meters) long.

Whales may seem tough. Knowlton describes their skin as hard like a rubber car tire. “But the steel propeller on a boat is like a sharp knife,” says Knowlton. The force of a ship hitting a whale causes severe injuries.

Calvin (the name stuck even though researchers later figured out she was a girl) has had many adventures. She got tangled in fishing gear and dragged it around for a long time before getting free. Calvin was luckier than a lot of whales who die when they are caught in fishing gear.

Calvin survived, and had a calf of her own in 2005. That calf should have a better chance for a long life, thanks to the proposed speed limits. And yes, the calf’s name is Hobbes.

Fast Facts

* Only about 350 North Atlantic right whales survive today.
* North Atlantic right whales don’t all look the same; researchers can tell them apart using photos because each has distinctive callosities (kuh-LAHS-uh-teez) or bumps of raised tissue, on their heads.
* These animals got their names before 1935 when hunting them was legal. They were known as the “right” whales to kill. Nowadays people still endanger them, but in different ways: many are injured or killed when hit by ships or tangled in fishing gear.

Drinking Water: Bottled or From the Tap?


Text by Catherine Clarke Fox
If your family is like many in the United States, unloading the week’s groceries includes hauling a case or two of bottled water into your home. On your way to a soccer game or activity, it’s easy to grab a cold one right out of the fridge, right?

But all those plastic bottles use a lot of fossil fuels and pollute the environment. In fact, Americans buy more bottled water than any other nation in the world, adding 29 billion water bottles a year to the problem. In order to make all these bottles, manufactueres use 17 million barrels of crude oil. That’s enough oil to keep a million cars going for twelve months.

Imagine a water bottle filled a quarter of the way up with oil. That’s about how much oil was needed to produce the bottle.

So why don’t more people drink water straight from the kitchen faucet? Some people drink bottled water because they think it is better for them than water out of the tap, but that’s not true. In the United States, local governments make sure water from the faucet is safe. There is also growing concern that chemicals in the bottles themselves may leach into the water.

People love the convenience of bottled water. But maybe if they realized the problems it causes, they would try drinking from a glass at home or carrying water in a refillable steel container instead of plastic.

Plastic bottle recycling can help—instead of going out with the trash, plastic bottles can be turned into items like carpeting or cozy fleece clothing.

Unfortunately, for every six water bottles we use, only one makes it to the recycling bin. The rest are sent to landfills. Or, even worse, they end up as trash on the land and in rivers, lakes, and the ocean. Plastic bottles take many hundreds of years to disintegrate.

Water is good for you, so keep drinking it. But think about how often you use water bottles, and see if you can make a change.

Betty McLaughlin, who runs an organization called the Container Recycling Institute, says try using fewer bottles: “If you take one to school in your lunch, don’t throw it away—bring it home and refill it from the tap for the next day. Keep track of how many times you refill a bottle before you recycle it.”

And yes, you can make a difference. Remember this: Recycling one plastic bottle can save enough energy to power a 60-watt light bulb for six hours.

Scientists Help Giant Pandas Raise Twins


Any human mother of multiples knows it's hard to raise two or more children of the same age at the same time. And it's true for other mammals, too.

"Nearly half of all giant panda births in zoos and research stations result in twins," Don Lindburg says. Lindburg is the leader of the giant panda research team at the San Diego Zoo.

"Taking care of tiny infants is an awesome chore, and mother pandas usually can't handle two," Lindburg says.

"Every newborn panda is important," says Lindburg "After giant pandas have grown to adulthood, some of the captive-born bears could be released into the mountainous wilds," he says. Those that mate and give birth to more cubs will help rebuild China's perilously small population of wild pandas.
At China's Wolong facility, caregivers are helping make the mother's situation more "bear-able." They gently remove one of the twins, keeping it warm and well fed for a week before trading it for the cub's brother or sister.

The cubs continue to be swapped for months, until they can eat solid foods and no longer need to nurse.

Bamboo, apples, carrots, and biscuits are added to the diet of mother's milk when the cubs are about seven months old. By adulthood, the pandas will eat fresh stems, shoots, and leaves of wild bamboo plants.
Fast Facts

* In five years female cubs will be mature enough to give birth to cubs of her own.
* Sixteen pandas were born in Wolong Nature Reserve in 2005.

Crafts : Dog Bed


Dog Bed



Your dog will love hanging out on this cool cushion.
YOU WILL NEED

* Fleece fabric in two colors (available at fabric stores); the amount of fabric depends on the size of your dog
* Ruler
* Fabric scissors
* Polyester pillow stuffing
* Optional: other colors of fleece to decorate the pillow

HERE'S HOW

Determine the dimensions your pillow needs to be to fit your dog, then add eight inches (20 centimeters) to the length and width. (This gives you extra fabric for fringe.)
Measure two colors of fleece to this size and align both pieces. To create the fringe, cut strips four inches (10 centimeters) long by one inch (2.5 centimeters) wide along all four sides of both pieces of fleece.
Cut out the squares of fabric at the corners. (If you like, cut extra fabric into fun shapes and sew them onto the fleece that will form the pillow’s top.) Tightly knot the top strips to the bottom strips on three sides of the pillow.
Stuff the pillow filling into the open side until the pillow is firm. Then tie the last side together.

Text by National Geographic Kids staff

Photograph by Rebecca Hale/NGS staff

Crafts : St. Patrick's Day Clover Pin





St. Patrick's Day Clover Pin



YOU WILL NEED

* Three green lollipops
* Twist tie
* Ribbon
* Tape or hot glue
* Large safety pin



HERE'S HOW



1. Crisscross two lollipops and place one lollipop in the middle to form a shamrock. Secure lollipops with a twist tie and decorate with a ribbon.

2. With the help of an adult, use either a strong piece of tape or hot glue to attach a large safety pin to the back of the top lollipop. Let glue dry.

3. Pin on clothes to ward off St. Patrick's Day pinches!

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