Volcanoes

What is the opening in Earth's crust through which molten rock, gases, and ash erupt?

• Divergent Boundary
• Magma
• Subduction Boundary
• Volcano

What is molten rock that has formed deep within the Earth?

• Hot Spot
• Magma
• Lava
• Volcano

Why does magma tend to rise to the surface?

• It has large amounts of silica.
• It contains very little silica.
• It is denser than the surrounding material.
• It is less dense than the surrounding material.

The formation of magma depends on which set of conditions?

• Pressure, Density, and Water Content
• Temperature, Density, and Pressure
• Temperature, Density, and Water Content
• Temperature, Pressure, and Water Content

The volcanoes on the Hawaiian Islands form due to which of the following?

• Divergent Boundary
• Hot Spot
• Subduction Boundary
• Transform Boundary

What is the principal ingredient to all types of magma?

• Iron
• Magnesium
• Silica
• Water

What type of lava cools quickly and forms rock with jagged edges?

• Aa
• Magma
• Pahoehoe
• Pillow Lava

What type of lava cools slowly and forms rock with smooth, ropelike features?

• Aa
• Magma
• Pahoehoe
• Pillow Lava

Which type of magma has the lowest amount of silica content?

• Andesitic Magma
• Basaltic Magma
• Rhyolitic Magma
• Viscous Lava

What is the resistance of a liquid, such as lava, to flow?

• Elasticity
• Pyroclasticity
• Silica
• Viscosity