The Topic: 

Easier -A volcano is a mountain topped with vents, holes, and craters. When the volcano erupts, lava, ash, cinders, dust, and hot gas can pour out the top. Magma (when it's deep in the ground) or lava (when it reaches the earth's surface) is very hot, liquid rock. When the lava cools down, it turns into hard rock. Ash is a gray powder that results from material being burned in the volcano. Ash can be carried in the air for many miles.
Harder - Volcanoes occur along the earth's tectonic plates where molten rock is forced upward from magma reservoirs deep in the earth. The magma may be fifty to one hundred miles below the ground. As the magma rises, it gives off gases that cause an explosion in the vents of the volcano. Lava can reach temperatures of over 2000 degrees F. Molten rock, dust, and gases push through the opening in the earth's crust and form a mountain. A violent explosion can cause the top of the volcano to blow off leaving a deep crater.
There are four types of volcanoes: active, intermittent, dormant, and extinct. Volcanoes can occur on land or in the water.
Formation of a Volcano
This is a good introductory illustrated site for volcanoes.
Volcano World (University of North Dakota
This site provides volcano information including identifying currently erupting volcanoes, a collection of volcano images and video clips, plus volcano parks, monuments, and observatories.
Webpages within Volcano World:
2) 'Kid' Door
3) Building Volcano Models
4) Do You Want to Become a volcanologist?
5) Top 101 Ask a Volcanologist Questions
6) Volcanic Rocks
Related Website:
7) Volcanologists or Volcanology 
Savage Earth: Out of the Inferno
This companion site to the PBS series has pictures, movies, and explanations of what causes volcanoes and what happens when they erupt.
Volcanoes by Wheeling Jesuit University/NASA Classroom of the Future
This is a great site to learn about types of volcanoes, lava, and see some animations of eruptions.
Choose a project and use the links below to solve the problem or complete an activity:
My Favorite Volcano. Pick a volcano to explore. Visit sites like Volcano World and Earth's Active Volcanoes to learn as much as you can about your volcano. Mark the location of the volcano on the map and attach a picture from the Internet. Describe the interesting characteristics of this volcano. Compare and contrast two different volcanoes.
Volcano Videos. Choose a volcano video and incorporate it into a HyperStudio project on volcanoes.
Create a Volcano Model. Create a paper mache or clay model of a real volcano eruption. Paint the model. For a more active model, visit Modeling An Active Explosive Volcano (Grades 3 - 6) and Volcano. To see all kinds of volcano model ideas, visit Building Volcano Models.
Complete a Volcano WebQuest. Complete one of the following volcano quests. Note that you may have to adapt the guidelines to fit: 
1) In Search of the Ring of Fire by T. Leslie
2) Seismology and Volcanology: The Study of Earthquakes and Volcanoes
3) Volcano WebQuest (Grade 4)
4) Volcanoes!
5) Volcanoes (4 Quests in One)
6) Volcanos WebQuest
7) Watch Out For That Volcano! (Grade K-2)
8) WebQuest about Volcanos
9) Will That Volcano Spoil Our Party? by B. Byles
Be a Reader. Read Volcano: The Eruption and Healing of Mount St. Helens.
Websites By Kids For Kids
Amazing Volcanoes Around the World (2000 ThinkQuest Junior Project)
Do you want to know how volcanoes are formed, discover the different types of volcanoes find out what the major volcanoes of the world are (including the Ring of Fire), look for use of volcanic materials in our environment or test your knowledge about volcanoes?
Amazing World of Volcanoes (1999 ThinkQuest Junior Project)
This site contains information about how volcanoes are formed, why they erupt, and Mt. St. Helens.
E komo mai. Nou ka hale or How Our Hawaiian Islands Were Formed (1999 ThinkQuest Junior Project 
This site focuses on the creation and the natural destruction of the Hawaiian Islands. It includes a section on lava and lava comparison.
Another ThinkQuest Project on Hawaiian Volocanoes:
2) Eruptions (2000 ThinkQuest Junior Project)
Erupting Education (2000 ThinkQuest Junior Project)
Learn about volcanoes, their geological history, and how they work.
Inside Volcanoes (2001 ThinkQuest Junior Project)
This site concentrates on the volcano basics including volcano types, what occurs inside a volcano, and what happens when they erupt.
This site contains facts, photos, and links on the causes and effects of volcanoes.
Volcanoes (1998 ThinkQuest Junior Project
The website provides information on eruptions, how volcanoes erupt and other volcano facts.
Volcanoes (1999 ThinkQuest Junior Project)
Here you can learn about different kinds of volcanoes, how they erupt and the side effects of these eruptions. You also study Mount St. Helens and Mount Vesuvius.
Volcanoes Around the World
Kapunahala 4th graders challenge your knowledge of volcanoes around the world. See if you can identify different volcanoes from various clues!
Volcanoes - Eruption and Destruction (1999 ThinkQuest Junior Project)
This site examines the formation of volcanoes and their state before, during, and after eruption.
Volcanoes Online (1998 ThinkQuest Project
Here you can find information about volcanoes and plate tectonics. It also includes a database with information on specific volcanoes.
More Sites
Can We Predict Volcanic Eruptions? from Annenberg/CPB
Explore this geologic question online.
Electronic Volcano (Dartmouth College
Here you can find many types of materials on active volcanoes worldwide, such as maps, photographs and full texts of dissertations and a few elusive documents.
Fact Sheet: Volcanoes at the Federal Emergency Management Agency
If you live near a known volcano, active or dormant, be ready to evacuate at a moment's notice with these tips.
Fallout: Eye of the Volcano from National Geographic
Learn what forces inside the Earth come together to create volcanoes like the one in Montserrat.
Global Volcanism Program at Smithsonian Institute, Museum of Natural History
This program seeks better understanding of all volcanoes through documenting their eruptions--small as well as large--during the past 10,000 years.
Terrestrial Volcanoes (Mirror Site)
The website includes a definition of volcano eruption, video and images, and volcano information.
Volcano Facts
Learn what causes volcanoes, read case studies, and find out if you can predict when eruptions occur.
Volcano Page
Learn what a volcano is, get interesting volcano facts, read about famous volcanoes, or browse through a glossary of volcano terms.
Volcanoes of the United States from the U.S. Geological Survey
This online version of a book by S. R. Brantley includes information on active volcanoes across the U.S. and plate tectonics.
Other U.S. Geological Survey Sites:
2) Volcano Hazards Program
3) Cascades Volcano Observatory
4) Monitoring Active Volcanoes
5) Volcanoes
6) Volcanoes!
7) Volcanoes of the United States
Earth's Active Volcanoes
Connect to websites on active volcanoes, indexed by geographic region.
Eruptions of Mount St. Helens: Past, Present, and Future
This online version of a book has tons of information on the past and current status of this volcano.
Related Sites:
2) Eruptions of Mount St. Helens: Past, Present, and Future 
3) Mount St. Helens
4) Mount St. Helens: A General Slide Set
5) Mount St. Helens, Washington, Mount St. Helens National Volcanic Monument
Hawaiian Volcano Observatory (U.S. Geological Survey)
This site summarizes volcanic activity in the Hawaiian Islands with both text and photographs.
Related Website:
2) Eruptions of Hawaiian Volcanos: Past, Present, and Future
3) Hawaii Volcanoes National Park
4) Volcanic and Seismic Hazards on the Island of Hawaii
Fallout: Eye of the Volcano from National Geographic
Here you find out how planetary forces laid the groundwork for the eruption on the tiny Caribbean island of Montserrat, how the toxic fallout affected the island's population, and what it has been like living with the fallout of the volcano.
Related Websites:
2) Soufriere Hills, Montserrat, West Indies
3) Soufriere Hills, Montserrat, West Indies
New Millennium Observatory 1998
Join scientists on trip to the bottom of the sea to research Axial volcano, located underwater on the Juan De Fuca plate 300 miles off the Oregon Coast. Site includes an Education section with ideas for the curriculum and teachers.
Stromboli On-line
This picture website shows recent and ongoing activity of Stromboli, an Italian island volcano, and other volcanoes.
Volcano Cam
'We've got lava' proclaims a Volcano Cam from New Zealand. Here, you're watching the Ruapehu volcano. Since nothing much usually happens (Usually see a picture from the archives), you can sign up to be notified by email as soon as she starts to erupt.
Another Volcano Cams:
2) Volcano Cam at Mt. St. Helens, WA
3) Volcanic Live Cams All Over the World from Stromboli On-Line
Websites for Teachers
Volcanoes! at USGS Learning Web (Grades 4-8) 
Here are 6 lessons plus a teacher's guide in the PDF format. Click and download.
Volcanoes Theme Page (NASA's Classroom of the Futureª, Grades 9-12)
Students are faced with a real life problem and their goal is to use problem solving skills and Internet-based data (e.g., remotely sensed satellite images) to propose and defend a solution. A teacher's guide is available.
Volcanoes (Grades 4-8)
This lesson leads students to look at one of the exciting aspects of volcanoes - how explosive they are - and see how this relates to where they are found.
Volcano Lesson Plans at Volcano World
Here are a few lessons and activities to get you started, more are being added.
World of Volcanoes (Grades 4-6)
Here is a plan for making a model volcano.
ash fall
Mt. St. Helens
block lava
tree mold
tectonic plate
volcanic rock
lava tube
titanium magnetite
convection current
molten rock
cinder cone
subduction zone
'ring of fire'
fault zone
shield volcano
mud flow
lateral blast
rock fall
lava cone
hydrothermal vents
secondary eruption
Created by Annette Lamb and Larry Johnson. Updated by Nancy Smith, 8/01