Magma Composition and Viscosity

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

• Hot Spot
• Magma
• Lava
• Volcano

Vocanoes are found...

• on land
• under water
• on islands
• all of the above

Which one of these does NOT affect the temperature at which magma forms?

• Pressure
• Composition of material
• Water
• Viscosity

What is the most explosive type of magma?

• Rhyolitic Magma
• Andesitic Magma
• Basaltic Magma

Which type of magma has the lowest gas content?

• Basaltic Magma
• Andesitic Magma
• Rhyolitic Magma

Usually found at subduction zones

• Andesitic Magma
• Basaltic Magma
• Rhyolitic Magma

As the temperature of lava increases, ________

• its viscosity decrease
• it begins to harden
• its viscosity increases
• it can flow a much short distance

The composition of magma determines its _____.

• viscosity
• darkness
• color
• none of the above

TRUE OR FALSE:  A substance that flows quickly has high viscosity...

• True
• False

Very explosive volcanoes tend to have

• Low viscosity magma
• Gases rich in sulfur dioxide
• gentle, sloping sides
• High viscosity magma