| A | B |
|---|
| Volcano | A weak spot in the crust where magma has come to the surface. |
Magma,  | The molten mixture of rock-forming substances, gases, and water from the mantle. |
| Lava | Liquid magma that reaches the surface; also the rock formed when liquid lava hardens. |
| Ring of Fire | A major belt of volcanoes that rims the Pacific Ocean. |
| Hot Spot | An area where magma from deep within the mantle melts through the crust above it. |
| Physical Property | Any characteristic of a substance that can be observed or measured without changing the composition of the substance. |
| Chemical Property | Any property of a substance that produces a change in the composition of matter. |
| Viscosity | The resistance of a liquid to flowing. |
| Silica | A material found in magma that is formed from the elements oxygen and silicon. |
Pahoehoe,  | A hot, fast-moving type of lava that hardens to form smooth, rope like coils. |
| AA | A slow-moving type of lava that hardens to form rough chunks; cooler than pahoehoe. |
| Element | A substance that cannot be broken down into other substances. |
| Compound | A substance in which two or more elements are chemically joined. |
| Magma Chamber | The pocket beneath a volcano where magma collects. |
| Pipe | A long tube through which magma moves from the magma chamber to Earth’s surface. |
| Vent | The opening through which molten rock and gas leave a volcano. |
| Crater | A bowl-shaped area that forms around a volcano’s central opening. |
| Dormant | Describes a volcano that is not currently active, but that may become active in the future. |
| Extinct | Describes a volcano that is no longer active and is unlikely to erupt again. |
Shield Volcano,  | A wide, gently sloping mountain made of layers of lava and formed by quiet eruptions. |
| Cinder Cone Volcano | A steep, cone-shaped hill or small mountain made of volcanic ash, cinders, and bombs piled up around a volcano's opening. |
Composite Volcano,  | A tall, cone-shaped mountain in which layers of lava alternate with layers of ash and other volcanic materials. |
| Caldera | The large hole at the top of a volcano formed when the roof of a volcano’s magma chamber collapses. |
| Batholith | A mass of rock formed when a large body of magma cools inside the crust. |
Geyser,  | A fountain of water and steam that builds up pressure underground and erupts at regular intervals.. |
| Volcanic Neck | A deposit of hardened magma in a volcano’s pipe. |
