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KA-BOOM! On May 18, 1980 Mount Saint Helens blew up. The ground shook and rumbled! A huge ash cloud covered the sun. Day turned into night. The blast flattened forests below the mountain. Hot gases and steam escaped. Snow and ice melted instantly! Huge mud slides rolled down the mountain. A volcano (vol-ca-no) had erupted (erupt-ed)!

What Are Volcanoes?

Volcanoes can be a tall mountains. They can also be cracks in Earth's surface. Layers of ash and lava (la-va) form volcanoes. Red hot lava is molten (mol-ten) rock. It flows out and cools to form the volcano. Inside the volcano, lava is called magma (mag-ma). Earth uses volcanoes as one way to cool itself. Earth's crust is broken into huge tectonic plates (tec-ton-ic plates) of solid rock. These plates are giant rock slabs. They move over a floating layer of hot, gooey rock called the mantle (man-tle). The mantle surrounds Earth's super-hot core. Earth's tectonic plates crash and slide over each other. They can form vents or cracks in Earth's crust. Magma rises from the mantle through these vents or cracks releasing hot ash, gases and molten lava.

Why are Volcanoes Important?

Volcanoes can be helpful, too. When hot ash and molten rocks cool and break down, they recycle (re-cy-cle) minerals in the soil for growing plants. Volcanoes also build new land, like the Hawaiian Islands (Ha-wai-ian Is-lands). They can even provide heat and energy to homes and businesses. Read more about volcanoes in books and on the Internet.


Circling the Pacific Ocean are a string of volcanoes creating a "Ring of Fire." Over 500 active volcanoes are found in this area.


Complete the crossword puzzle.


1. melted rock inside Earth

2. the outer layer of Earth

3. melted rock that flows out of a volcano

4. the center of Earth

5. slabs of rock that make up the crust


6. hot, gooey layer under Earth's crust

7. cracks in Earth's crust where magma escapes

8. grayish flakes and powder left after something burns

Weekly Lab

Hot gases and lava come out of volcanoes. Some lava is thick and some is runny. Which kind of lava would form a tall volcano? Which kind would form a wide volcano? How do you think the hot gases effect the lava flow? Write down your hypothesis and complete this WEEKLY LAB to see if you are right. Write down your results and explain.

You need: large pan, newspapers, play dough, clay or brown kraft paper, tape, 2 tall containers, measuring spoon, baking soda, red and yellow food coloring, measuring cup, vinegar, alum powder and unflavored gelatin


Step 1: Lay the pan on some newspaper. Place one of the tall containers in the pan. Use play dough, clay or taped kraft paper over stuffed newspaper to shape the mountain. Place around the container. Leave the top of the container open for the crater.

Step 2: Pour 15 ml (1 Tbl.) of baking soda into the container. Add 4 drops each of red and yellow food coloring.

Step 3: Pour in 60 ml (1/4 cup) of vinegar. Watch out!


Step 1: Place a new container in the volcano.

Step 2: Mix together 15 ml (1 Tbl.) each of baking soda, alum and gelatin. Pour the mixture into the crater. Add food coloring (same as Experiment A).

Step 3: Pour 60 ml (1/4 cup) of vinegar into the container. Here it comes!


The Earth's tectonic plates move very slowly. The Pacific plate moves about 5 centimeters per year. The Atlantic Plate moves about 10 centimeters per year. Your fingernails grow about 4 centimeters per year! Use a ruler to answer the questions. Show your work.

How far does the Pacific plate move in three years?--cm

How far does the Atlantic plate move in seven years?--cm

Measure this line:--It is--cm long.

How many years would it take for the Atlantic plate to move the same distance as this line?--years

The Pacific plate?--years

writing in Science

Long ago, people created myths or stories to explain volcanoes. Read about one of these myths in the box below, then create your own myth about volcanoes. Describe how they were formed.

The ancient Romans believed Vulcan, the god of fire and metal, lived in a volcano. He built his blacksmith shop under certain mountains. Whenever he was working, smoke and fire flew from Vulcan's chimneys.


In March 2005, Mount Saint Helens rumbled. Ash clouds shot up in the sky! Scientists are StUdying the mountain to see if it will erupt once more!


Write in the matching volcano name or lava name under the correct picture. Use the bolded words in the yellow box to the left.

Lava flows and volcanoes are not all alike. The Hawaiian people have special names for two types of lava flows. Pahoehoe lava (pah-hoh-ee-hoh-ee lava) flows look like shiny ribbons of cake batter. 'A'a lava (ah-ah lava) flows look like rivers of slow moving, crunchy spiky rocks.

Many Hawaiian volcanoes are wide shield volcanoes. They are formed by fast moving, runny lava. Stratovolcanoes, like Mt. St. Helens, are tall explosive mountains. They erupt with lots of hot ash, rocks, gases and thick lava.

Can you make 10 words out of these syllables? Write them below. Use all
of the syllables. Do not use any more than once.

vol erupt tonic
pl cano moun
ed la min
mag man ates
ma va er
Vul tec als
tain can tle












Mauna Loa is the tallest volcano on Earth (9,000 meters). It covers half the Island of Hawaii.

About 50 volcanoes erupt on Earth every year.



KA-BOOM!!! On May 18th, 1980 Mt. St. Helens in Washington State exploded. A 5.1 magnitude earthquake triggered the volcano's northern flank to collapse, causing a huge avalanche. Within 30 seconds, over 400 meters of the mountain blew up in ash, dust and debris. On March 8th, 2005 near its 25th anniversary date, Mt. St. Helens rumbled spewing ash 30,000 feet into the air. Molten lava was visible in the volcano's crater. Volcanologists, scientists who study volcanoes, are closely monitoring Mt. St. Helens for future explosions.

Molten Earth

Over 4 billion years ago, scientists believe Earth was a homogenous mass of molten rock. Gradually, geological layers or tectonic plates evolved and created Earth's crust (100 km deep) from cooling, crystallized magma. Floating on Earth's mantle (2,900 km wide), the crust protects us from underlying, molten magma. Below the mantle lies Earth's outer core (2,200 km wide). The inner core is approximately 1,250 km wide, with Earth's center reported to be 6,378 km deep.

Our Earth is actually a heat engine. It uses volcanoes to cool down by releasing internal heat and pressure. Volcanoes are not randomly distributed around Earth, but are confined to active margins of Earth's tectonic plates. Volcanoes occur where plates collide (subduction zone), drift or tear apart (mid-oceanic rifts), or are produced on thin, weak spots in Earth's crust (hot spots). All volcanoes are fueled by a hot sea of molten, pressurized magma lying below Earth's crust. Magma is less dense than solid rock, and floats upwards to the surface. As two tectonic plates pull apart overlap, hot liquid magma rises to fill gaps releasing heat, energy, gas, and molten minerals. Interaction between the amount of heat, pressure, gas, and magma's chemical and mineral composition determine a volcano's explosive nature.

Types of Volcanoes

Volcanoes are the only land formation created by the accumulation of lava flows and fragments, bombs (house-sized rocks) or airborne ash. Red volcanoes are dominated by glowing, oozing red lava (Mauna Loa on Hawaii). Grey volcanoes erupt explosively spewing out ash, cinders, pumice, lava boulders and toxic gases (Mt. St. Helens).

Lava dome volcanoes are created from viscous, slow moving lava squeezed up into a steep sided plug over its central tube. Cinder cone volcanoes arise from solid lava fragments thrown out to form a cinder pile. Shield volcanoes occur when very fluid lava flows long distances on gentle slopes. Composite cone or stratovolcanoes are created from alternate layers of explosive ash and lava flow eruptions. Underwater, submarine volcanoes are typically cone-shaped with steep sides (water cools lava faster than air). After a large volcanic explosion, empty magma chambers can collapse to form calderas, large circular basins with steep walls. Hot spots are thought to be cooled plumes of thin volcanic material moving over pooling magma (Hawaiian Islands).

Heat, the thickness or viscosity, mineral composition and absorption of gases influence lava flows. Viscous (sticky and slow moving) lava has high silica content and can plug volcano vents (just like a cork). Pillow lava flows occur in underwater vents and look like rolling globs of lava. Pahoehoe lava flows appear to look like shiny, smooth ribbons of cake batter. A lava looks like fragmented, crystallized crunchy flows.

Deadly Forces

The most violent volcanoes are primarily located where two tectonic plates collide (subduction zones). Nuee ardentes, or pyroclastic flows combine glowing ash, fist to house-sized lava bombs and superheated gases that explode out from erupting volcanoes. Toxic sulfur dioxide, carbon dioxide and radon gases spew out of volcanic vents. Lahars or heavy mud flows can bury villages, and clog rivers. Gigantic landslides can cause huge tsunamis, or tidal waves. Dramatic lightning storms can rage over volcanic eruptions, due to the introduced atmospheric ash. And with volcanic eruptions, earthquakes can occur before and after.

Volcanic Treasures

Underwater rift chimneys can spout black clouds containing silver and gold deposits. Ash, lava and pumice break down releasing minerals to replenish soil matter. Geothermal energy releases steam heat and energy from geysers and hot springs. Volcanoes can destroy, but they also provide opportunity and new life.

Level Pre-A

1. What is a volcano?

2. What makes a volcano?

3. What happens when a volcano blows up?

Follow-up Questions

4. Where does lava come from?

5. If a volcano has snow on top, is the volcano asleep or awake?

6. Can a volcano wake up and explode?


Answers: tall, saw, fall, small

Ask students to fill in the blank spaces with the letter "a" (sounds like "ah"). Have students make up sentences using the words, like "I saw a tall volcano. It is not small."

Weekly Lab--How Are Volcanoes Made?

In this lab, students mix vinegar and baking soda to demonstrate how lava travels out a volcano. Explain that lava is very, very hot melted rock. Inside the volcano, hot lava is called magma. Adding vinegar to baking soda creates a chemical reaction. Liquid froths and bubbles up, just like hot lava. Discuss whether the lava is thick or runny, fast or slow moving.


Answer: 5 volcanoes

Volcanoes can be mountains, but all mountains are not volcanoes. Some volcanoes can also be dormant or asleep. Have the students circle the volcanoes and put the correct number in the boxes.


Ask students to describe a volcanic eruption. Hot magma bubbles to the surface through cracks in the volcano. As it rises through a central tube, magma escapes as hot lava, ash and gas. Lava flows down the mountain. Layers of hot ash and lava collect to make a volcano.


WHY FLY is observing a volcanic eruption. Reinforce the concept that volcanic eruptions release tremendous forces. (See next page for solution to the maze.)

Bringing It Home

At home or in class, the students will be making an erupting volcano model. On the cup, glued-on black and brown paper represents layers of ash and lava forming the volcano. Red lava (red yarn) flows down the volcano sides. Clouds of ash and smoke (cotton balls and glitter) rise above the volcano. On the plate, glued-on green paper represents the forest or jungle below.

Level A

1. What makes a volcano?

2. How can lava flow up and out of a volcano?

3. Rub your hands together. What do you feel? How can rock melt?

4. Do people live near volcanoes? Why or why not?

5. Besides lava, what else comes out of a volcano? What makes you burp?

6. If a volcano is quiet, does that mean it's extinct (dead) or asleep? Why?


Have the students read the words and write them in the spaces provided. Ask students to match contrasting words--cold, hot; over, under; up, down.

Through this activity, students learn that lava quickly can erupt from volcanoes. Adding extra vinegar to the baking soda increases the chemical reaction and release of carbon dioxide gas. With increased gas, lava can explode out as grey to black lava rock, hot ash and cinders. Discuss with students the different types of volcanic eruptions.


Answer: 3 active + 5 quiet = 8 volcanoes

Students choose between active and dormant (quiet) volcanoes. Before 1980, Mt. St. Helens was dormant for 123 years. In March 2005, Mt. St. Helens became active again.

Writing For Science

Encourage students to use nouns to complete full sentences as they describe a volcanic eruption.


Magma rises through volcano cracks or vents, releasing hot ash, gas, and molten lava. Reinforce the concept that volcanic eruptions release tremendous forces.

Bringing It Home

At home or in class, students can build a volcano model. Students can demonstrate how hot lava (red yarn) flows down the black and brown volcano flanks (glued-on paper) to the forest below (green paper on plate). Steam and ash (cotton balls, glitter) rise from the volcano's crater. A huge ash cloud (tinfoil square) billows out of the volcano.


Volcanologists think that a full moon's gravitational pull may increase the frequency of volcanic activity. Just like tidal action, a full moon's gravitational pull may draw more magma up the volcano, and can cause periods of greater volcanic eruptions.

Level B

Initiating Questions

1. What do you think makes volcanoes blow up?

2. Can we travel inside a volcano to watch an eruption?

3. Why is it important to have volcanoes?

Follow-Up Questions

4. Are there different types of lava flows? What would they look, feel and smell like?

5. Can you tell what kind of volcanic eruption occurred from old lava flows?

6. What are some strong clues that tell volcanologists a volcano may erupt?


Answers: ash, crust, lava, magma, molten, mountain, and volcano

Students complete the puzzle by circling the listed words.

Weekly Lab

Students will observe the eruptive nature of lava and the different viscosity, or thickness of lava. Thick or viscous lava does not flow fast and runny. It can plug up a volcanic vent creating dome volcanoes. The baking soda and vinegar create a chemical reaction, releasing carbon dioxide gas and causing a liquid eruption. When volcanoes erupt, hot magma and gas can flow out as molten lava or explosive ash clouds, cinders and pumice. The molasses is similar to thick, runny lava found on non-explosive, shield volcanoes. Both are liquid and runny. The vinegar lava moves faster and has more gas. It is more explosive. The molasses represents thicker, low-gas lava similar to pahoehoe lava.


Answers: From largest to smallest--Mt. Tambora (Indonesia), Mt. Katmai (Alaska), Mt. Pinatubo (Philippine Islands), Mt. Vesuvius (Italy), Mt. St. Helens (Washington).

For enrichment, teachers can ask students to find each volcano's location. Mt. is an abbreviation for Mount (mountain).

Writing For Science

Encourage students to brainstorm putting descriptive words together. Have students ever observed a volcanic eruption? Reinforce the concept that volcanic eruptions release tremendous forces.


Answer: B is the active volcano.

Ask students if they can tell the difference between a non-volcanic mountain and a quiet volcano. What would be the clues? (prehistoric lava flows, formation, crater on top, weathering, rock types and age of vegetation)


Answer: "If you walked on hot lava with bare feet, you would say aah-aah!"

Volcanoes influence many cultures and their languages.


About 50 volcanoes erupt every year.

Mt. Etna in Italy has been continuously erupting for over 3,500 Years

Level C

Initiating Questions

1. What can volcanoes tell us about the center of Earth?

2. What is the difference between lava and magma?

3. How do volcanoes help Earth and living things?

Follow-up Questions

4. What do you think a planet requires for volcanic activity?

5. How can a volcano have gentle to explosive eruptions?

6. Would it be safe to live near a volcano? Why or why not?


Answers: lava, mantle, plates, ash, crust, core, vents, and magma

Direct students to complete the crossword puzzle.

Weekly Lab

Experiment A makes fast moving, gaseous lava. Experiment B makes less gaseous, somewhat thick lava. Cinder cone volcanoes are created by fountains of explosive, lava flows (similar to Experiment A lava). The lava is runny and full of explosive gas. Wide shield volcanoes are made from runny, low gaseous lava (created in Experiment B). Higher gas content influences a volcano's explosive lava flow.


Answers: 15 cm per year; 70 cm per year; 9 cm long; 1 year; 2 years

To demonstrate annual tectonic plate movement, ask students to draw a line measuring 5 centimeters and 10 centimeters long.

Writing For Science

Myths were often used to explain the unknown in various countries. Ask the students if they know any other volcano myths.


Answers: 1--'a'a lava; 2--pahoehoe lava; 3--shield volcano; 4--stratovolcano

Students will match the names to the appropriate pictures and write the word in the space.


Answers: volcano, erupted, tectonic, plates, mountain, lava, Vulcan, minerals, magma, and mantle

Direct students to make complete words out of the word clips. Encourage them to make multiple word phrases, like tectonic plates or erupted volcano.

Level D

Initiating Questions

1. What can volcanoes tell us about the center of Earth? Describe what elements and forces a planet needs for volcanic activity.

2. What forces cause magma to rise into volcanoes?

3. How do volcanoes help Earth and living things?

Follow-up Questions

4. Besides lava, what other deadly materials can explode out of a volcano?

5. Rub your hands together. What are you creating? Describe the natural forces that make rocks melt.

6. Why are people attracted to living next to a volcano? What are the dangers?

Answers: lava, mantle, plates, ash, poisonous, dormant, volcanologist, pumice, vents, magma, and geothermal

Direct students to complete the crossword puzzle.

Weekly Lab

Students are creating a fast-moving, gaseous lava and a less gaseous, somewhat thick lava. Increased gas absorption and lava viscosity increases a volcano's explosive nature. In experiment A, lava rose higher due to the chemical reaction and gas content. When gases combine with viscous lava, lava blasts out of the volcano as hot ash clouds, pumice, cinders or exploding lava rocks. Experiment A lava could build tall, cinder cone volcanoes, as carbon dioxide gases mix with fluid lava to create explosive lava cinders and fragments. In Experiment B, lava is thicker and slower moving, has less gas and is found on wide, shield volcanoes.


Answers: 1--8 days; 2--250 days; 3--354 days; 4--532 days

Students will add together Earth's layers to calculate individual, rounded answers.

Writing For Science

In the lab, Experiment A lava could be found in cinder cone volcanoes (Mt. Paricutin in Mexico). Experiment B lava looks like shiny ribbons of pahoehoe lava found on wide, shield volcanoes. Japanese scientists build lava diverters to redirect lava flows to protect businesses and homes.


Answers: 1--pahoehoe lava; 2--'a'a lava; 3--stratovolcano; 4--cinder cone volcano; 5--shield volcano

Match the words to the pictures and fill in the blanks under each picture with the correct description.

Meet the Scientist

Dr. John Wolff enjoys hunting down really old volcanic rocks. If you're interested in learning more about volcanoes and prehistoric lava flows, log on to:

Level E

1. Why are there so many active volcanoes around the Pacific Rim?

2. What materials form when you add gases to thick lava flows? What happens when a volcano is plugged by thick, viscous lava?

3. Can you think of any other methods scientists can use to study volcanic activity? Could the Moon's gravity increase the frequency of volcanic activity?

Follow-up Questions

4. Explain how a volcano is a natural recycling factory.

5. Describe two types of volcanic eruptions: one gentle and one explosive. Create a Venn diagram comparing similarities and differences.

6. How would a volcanic explosion effect global weather? Would the effects be short term or long term?


Answers: lava, mantle, plates, ash, poisonous, dormant, volcanologist, pumice, vents, magma, bombs, geothermal, Ring of Fire, and flank

Direct students to complete the crossword puzzle. (See next page for the solution to the puzzle.)

Weekly Lab

Lava flows can be fast or slow, runny to viscous. Engage the students in discussing different types of volcanoes, where they are located and types of explosions. Experiment A created fast moving, gaseous lava that could be found on taller, cinder cone volcanoes. Experiment B created a less gaseous, somewhat thick lava, similar to lava found on wide shield volcanoes. Molasses is more viscous than corn syrup and water. Increased silica and mineral content increases lava viscosity. Increased gas content can make lava more explosive.


Answers: 1. Mt. Katmai; 2. Yellowstone; 3. Mt. Vesuvius; 4. 198 cubic km, rounded; 5. Mt. Pinatubo;

Determining height on the chart--Mt. St. Helens (3, 2,549 m); Mt. Pinatubo (5, 1,486 m); Mt. Vesuvius (6, 1,281 m); Mt. Tambora (1, 2,850 m); Yellowstone (2, 2,805 m); Mt. Katmai (4, 2,047m)

Identify the highest to lowest volcano on the chart. Write in their height. Refer to the volcano pictured with the listed heights. Ask the students to work in pairs or groups to answer the questions.

Writing For Science

In the lab activity, students experimented making runny, gaseous lava and slow moving, low gaseous lava. Of the 1,500 active volcanoes on Earth, over 80% are found underwater. Most underwater volcanic activity is found in subduction and rift zones. As lava cools quickly and crystallizes in the cold water, it explodes and bursts.


Answers: 1--cinder cone volcano; 2--pillow lava; 3--stratovolcano; 4--'a'a lava 5--hot spot; 6--pahoehoe lava; 7--caldera: 8--shield volcano

Encourage the students to identify each volcano's location and how they developed.

Meet the Scientist

See TN--Level D.


Pumice or rock froth is made from the Violent separation of gas from lava. Some of this material is so light that it floats on water. In many eruptions, rock froth is shattered and hurled high into the air as volcanic cinders ash and dust.

Over 80% of the Earth's volcanoes are located under the oceans. Over 200 active volcanoes circle the Pacific Ocean creating a "Ring of Fire".

Test Taking Skills Level B

(Number 1)--to the right

Read the word in dark or bolded print. Look at the other words. Mark the box next to the word that has the same beginning sound as the word in bold print.

(Number 2)--to the right

Read the word in dark or bolded print. Look at the other words. Mark the box next to the word that has the same middle sound as the word in bold print.

(Numbers 3-5)--to the right

Read the word in dark or bolded print. Look at the other words. Find the word that has the same vowel sound as the word in bold print. Fill in the box in front of the answer you choose.

(Numbers 6-7)--to the right

Read the word in dark or bolded print. Now read the words below each bolded word. Find the word that has the same vowel sound as the bolded word. Fill in the box in front of the answer you choose.

(Numbers 8-9)--to the right

Read the word in dark or bolded print. Find the numeral that tells how many syllables are in the word. Fill in the box in front of the answer you choose.
1. lock

[] lake [] low
[] lava [] land

2. crust

[] crust [] ash
[] core [] moon

3. ash

[] soil [] rock
[] lava [] crack

4. crust

[] cool [] hot
[] flow [] stuck

5. shook

[] out [] comes
[] look [] tall

6. rumble

[] ground [] earth
[] grumble [] melt

7. sky

[] comes [] from
[] blew [] high

8. volcano

[] 1 [] 2 [] 3 [] 4

9. magma

[] 1 [] 2 [] 3 [] 4

Answers: 1--lava; 2--core; 3--crack; 4--stuck; 5--look; 6--grumble; 7--high; 8--3; 9--2

Test Taking Skills--Level D


(Numbers 1-2)--on the following page

Find the word that means the same, or about the same, as the boldfaced word. Fill in the space that goes with the answer you choose.

(Numbers 3-4)--to the right

Read the bolded word and definition. Now find a definition of the bolded word that is different but also describes the word. Fill in the space that goes with the answer you chose.

(Numbers 5-6)--to the right

Read the definition. Then read the sentences below the definition. Find the sentence that applies to the definition of the boldfaced word. Fill in the space that goes with the answer you choose.

1. explode

[] a. jump

[] b. blow up

[] c. melt

[] d. cool

2. imagine

[] a. think up an idea in your mind

[] b. order

[] c. activate

[] d. decide

3. crust--outside layer of Earth

[] a. hot molten rock

[] b. outer edge of a bread slice

[] c. gray burnt particles

[] d. broken up minerals

4. flank--side of a volcano

[] a. heated steam

[] b. a powerful force

[] c. side of an animal behind the ribs

[] d. stepping aside

5. a break, or to make something break apart

[] a. A crack in Earth's surface releases gas and lava.

[] b. Crack the door to let in some clean air.

[] c. Don't crack open the window to let in cold air.

6. a powerful motion or energy that something posesses

[] a. Don't force the boy to read the book.

[] b. He will force her to admit the truth.

[] c. Pressure and heat forces magma to rise to Earth's surface.

Answers: 1--b; 2--a; 3--b; 4--c; 5--a; 6--c


Some of the toughest pronouncing volcano names are Quezaltepeque (Guatemala), Xianjindao (North Korea), and Tindfjallajokull (Iceland).

Weekly Resources

Helpful Sources for Planning Your Science Weekly Classroom Activities

Recommended Resources

Grace, Catherine O'Neill, The Awesome Power of Volcanoes, Earthquakes and Tornadoes, National Geographic Society, Belgium, 2004.

Jennings, Terry, Volcanoes and Earthquakes, Sino Publishing House, Hong Kong, 2002.

O' Meara, Donna, Into the Volcano--A Volcano Researcher At Work, Kids Can Press, Toronto, 2005

Simon, Seymour, Danger! Volcanoes, Sea Star Books, New York, 2002.

Internet Resources projects/web/volcano/for-the-teacher.htm interactive/index.htm?section=v


Volcano's Deadly Warning, NOVA, BBC/WGBH Boston Co-Production, 2002 British Broadcasting Corporation.

Ring of Fire, Science Museum of Minnesota,, 2002.
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Title Annotation:educational exercises
Publication:Science Weekly
Date:Apr 11, 2005
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