Formation of Igneous Rocks

Identify the rock that is lightweight and porous.

• Granite

• Basalt

• Pumice

• Marble

What is magma?

• Molten rock above ground

• Molten rock underground

• Solid rock underground

• Solid rock above ground

Igneous rocks are formed from cooling _______.

• magma or lava

• sedimentary layers

• metamorphic minerals

• fossilized remains

The appearance of igneous rocks depends on cooling rate and _______.

• composition

• color

• density

• size

What is lava?

• Magma that reaches the surface

• Solid rock underground

• Molten rock underground

• Magma that stays below the surface

What is the difference between extrusive and intrusive igneous rocks?

• Extrusive rocks cool below the earth's surface, while intrusive rocks cool above.

• Extrusive rocks cool above the earth's surface, while intrusive rocks cool below.

• Both cool above the earth's surface.

• Both cool below the earth's surface.

How long does it take for flowing lava to cool?

• Minutes

• Hours to weeks

• Months

• Years

Ejected lava cools ____.

• instantly.

• slowly over days.

• in a few hours.

• after several weeks.

Why do extrusive igneous rocks have very small crystals?

• Because they cool quickly on the Earth's surface

• Because they are formed under high pressure

• Because they contain a lot of water

• Because they are formed deep within the Earth

Which of the following is a type of extrusive igneous rock?

• Granite

• Basalt

• Marble

• Limestone