1. Active Volcano- A volcano that shows signs of eruption or has erupted recently.
2. Ash- Small pieces of magma thrown out of a volcano. The ash pieces that fall near the volcano opening form the crater.
3. Caldera- A large circular hole, usually over a mile in diameter, produced when a volcano falls in on itself.
4. Cone Volcano- A steep, sloping volcano made of layers of ash and lava that builds up from past eruptions.
5. Convection- A circular movement in a liquid that carries heat from one place to another. In the earth, this happens in the mantle.
6. Crater- The large opening at the top of a volcano produced by the explosion of an eruption. It is smaller than a caldera.
7. Crust- The layer of a hard rock that surrounds the earth. It is between 21 and 125 miles thick.
8. Dormant Volcano- A volcano that has not erupted for a long time, but may erupt again one day.
9. Eruption- The sudden explosion of hot rocks, gases and other material through a hole in the earth’s surface.
10. Extinct Volcano- A volcano that hasn’t erupted for thousands of years and probably will not erupt again.
11. Geothermal Energy- Energy made by using underground steam; the steam produces electricity.
12. Lahar- A volcanic mudflow which is a mix of water, volcanic ash, and some gases which moves fast down a valley.
13. Lava- The hot liquid magma that flows from a volcano that is erupting. It is liquid magma without its gases. There are two main types of lava: thick sticky lava and liquid runny lava. It is usually orange, red, or yellow, and is over 1,470 degrees Fahrenheit.
14. Lava Flow- Liquid magma that flows from the volcano on the earth’s surface.
15. Magma- The melted rock produced inside the earth. When a volcano erupts, magma comes to the surface and is called lava.
16. Magma Chamber- An area filled with magma that lies beneath a volcano.
17. Mantle- The layer of hard rock immediately between the earth’s crust and its core. Beneath the mantle, some of the rocks are liquid and move.
18. Mudflow- A flow of water and debris that usually looks like brown liquid cement. Heavy rain, melting snow, and ash mix together during an eruption and produce mudflows.
19. Plate- A section of the earth’s crust made by weak spots in the earth’s crust and boiling magma. It floats on the mantle layer. Often volcanoes and earthquakes occur at the edges of the earth’s plate.
20. Volcanic Ash- Lava from a volcano that is in the form of chunks smaller than an apple, about the size of marbles.
21. Volcanic Bomb- A large lump of lava thrown out of a volcano during an eruption. A bomb usually starts as a flying blob of lava, but solidifies as it falls to the ground.
22. Volcanic Dust- Lava in the form of small, tiny particles thrown from a volcano during an eruption.
23. Volcanic Material- Lava, ash, and gases that are brought to the surface when a volcano erupts.