| A | B |
|---|
| What is a volcano? | a weak spot in the crust where molten material, or magma, comes to the surface |
| Where is the “Ring of Fire”? | rim of the Pacific Ocean |
| Where are most volcanoes located? | at or near plate boundaries |
| What happens at diverging plate boundaries? | volcanoes form when the plates move apart and lava oozes up |
| What happens at converging plate boundaries? | the older denser plate subducts, forming a volcano on the upper plate |
| How does a hot spot volcano form? | an area where material from deep within the mantle rises and then melts, forming magma. a volcano forms when magma erupts through the crust and reaches the surface |
| What is an element? | a substance that cannot be broken down into other substances |
| What is a compound? | a substance made of two or more elements that have been chemically combined |
| Each substance has a particular set of ____________________________________ ________________________________________ | physical and chemical properties |
| These properties can be used to ________________________________________ ______________________________________________ | identify a substance or to predict how it will behave |
| What is a physical property? | any characteristic of a substance that can be observed or measured without changing the composition of the substance |
| What is a chemical property? | any porperty that produces a change in the composition of matter |
| List examples of physical and chemical properties. | physical: density, hardness, melting point, boiling point. chemical properties: a substance's ability to burn |
| What is viscosity? | the resistance of a liquid to flowing |
| What affects the viscosity of magma? | silica content and temperature |
| How does silica content affect the viscosity of magma? | the more silica in magma, the greater the viscosity. the less silica in magma, the less the viscosity |
| How does temperature affect the viscosity of magma? | the greater the temperature, the less the viscosity. the lower the temperature, the greater the viscosity. |
| When a volcano erupts, ______________________________________________ ______________________________________________________________________ | the force of the expanding gases pushes magma from the magma chamber through the pie until it flows or explodes out of the vent. |
| What are the two types of eruptions? | quiet and explosive |
| Describe a quiet eruption. | low viscosity and low silica produces a shield volcano. the gases in the magma bubble out gently. Lava oozes quietly from the vent and can flow for many kilometers. |
| Describe an explosive eruption. | high silica: cinder cones and stratovolcanoes: the magma does not always flow. dissolved gases cannont escape from the thick magma. the trapped gases build up pressure until they explode. |
| What is pyroclastic flow? | occurs when an explosie eruption hurls out a mixture of hot gases, ash, cinders, and bombs |
| Example of a hazardous volcano. | Krakatau, Mount Pelee, Mount Katmai, Mt. St. Helens, Mount Pinatubo, Mt. Etna, Mt. Vesuvius |
| What are the three types of volcanoes? | shield, cinder cones, stratovolcano |
| What are lava plateaus? | areas built up of thing, runny lava that have formed layer after layer over millions of years. |
| What are calderas? | formed whne the roof of the empty magma chamber collapses |
| What features form as a result of magma hardening beneath Earth’s surface? | volcanic necks, dikes, sills, batholiths, and dome mountains |
| What are 2 ways in which mountains can form as a result of magma hardening beneath Earth’s surface? | batholiths are large rock masses that form the core of many mountain ranges. dome mountains form when uplift forces hardened magma to ben upward. |
| What is geothermal activity? | magma beneath the Earth's surface heats underground water |
| What are some features found in areas of geothermal activity? | geysers and hot springs |
