Lesson 3: Volcanoes Concepts: - One of the characteristics of a liquid is viscosity, or tendency to not flow. - Viscosity is principally dependent on the make-up and temperature of the liquid. - The shape of a mountain formed by volcanic eruptions depends on several factors, such as the properties of the volcanic material that comes out and the sequence and variety of eruptions. - Scientists classify volcanoes on the basis of shape and size. - The three most common types of volcanoes are composite volcanoes, shield volcanoes, and cinder cones Vocabulary: - Viscosity – the property of a liquid where its tendency is to resist flow. o Liquids with low viscosity tend to flow readily (example: water) o Liquids with high viscosity flow slowly (example: honey) - Composite Volcanoes- A steep volcanic cone built by lava flows and eruptions. Ex. Mt. Rainier in Washington State. - Crater- bowl shaped depression at the bottom of a volcano. - Shield Volcanoes- volcano that forms from lava that builds up slowly over time - Cinder- pebble sized rock fragments that have the same composition as ash. They are glassy and contain numerous bubbles created by the gas that escaped as the magma exploded into the air and then cooled quickly. - Cinder Cones- The simplest type of volcano that forms from congealed lava and rock fragments that have come out of a single vent. As the gas-charged lava blows violently into the air, it cools, turns into small fragments, and falls as cinders around and downwind from the vent to form a steep circular or oval cone.