IGNEOUS ROCKS

I. California K-6 standards for igneous rocks -

1. Kindergarten
1. Earth Sciences Topics
1. The Earth is composed of land, air, and water. As a basis for understanding this concept, students know:
1. how to identify resources from the Earth that are used in everyday life, and that many resources can be conserved.

 

2. Investigation and Experimentation
1. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept, and to address the content in the other three strands, students should develop their own questions and perform investigations. Students will:

1. observe common objects using the five senses.
2. describe the properties of common objects.

2. Grade 2
1. Earth Sciences Topics
1. Earth is made of materials that have distinct properties and provide resources for human activities. As the basis for understanding this concept, students know:
1. how to compare the physical properties of different kinds of rocks and that rock is composed of different combinations of minerals.
2. rocks, water, plants and soil provide many resources including food, fuel, and building materials that humans use.

 

2. Investigation and Experimentation
1. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept, and to address the content of the other three strands, students should develop their own questions and perform investigations. Students will:
1. compare and sort common objects based on two or more physical attributes (including color, shape, texture, size, weight).

3. Grade 4
1. Earth Sciences Topics
1. The properties of rocks and minerals reflect the processes that formed them. As a basis for understanding this concept, students know:
1. how to differentiate among igneous, sedimentary, and metamorphic rocks by their properties and methods of formation (the rock cycle).

4. Grade 6
1. Resources
1. Sources of energy and materials differ in amounts, distribution, usefulness, and the time required for their formation. As a basis for understanding this concept, students know:
1. different natural energy and material resources, including air, soil, rocks, minerals, petroleum, fresh water, wildlife, and forests, and classify them as renewable or nonrenewable.

II. Goals of This Module -

• To learn the processes that form igneous rocks.
• To learn the definitions of and proper spelling for scientific terms that are used commonly in newspapers, magazines, and books, and on television and radio programs to discuss igneous rocks.
• To learn how to identify the most common igneous rocks.
• To learn which igneous rocks serve as resources and how they are used in everday life.

III. Formation of Igneous Rocks -

• Igneous rocks form by cooling and solidification of molten rock -
• Ionic bonding of mineral compounds during the cooling process allows mineral crystals to form. The formation of these crystals in the molten material is called crystallization.
• When rock material is above melting temperature, the ions are spread out and are moving fast, so ionic bonds cannot form and the rock material is in its liquid or molten state.
• When molten rock cools, the ions move closer together and slow down, thus allowing ionic bonds to form so that the minerals can crystallize into a solid igneous rock.

IV. Origin and texture (crystal size) of igneous rocks -

V. Bowen's reaction series -

• The temperature at which a mineral either melts as it gets hotter or crystallizes as a body of magma gets cooler is different for each mineral. Some minerals will melt at 600°C and others require temperatures as high as 1,400°C. This relationship for the rock-forming minerals is described in Bowen's reaction series.

VI. Magma Composition -

• Magma composition depends on several factors -
• Original composition of the rocks being melted.
• Temperature obtained during melting.
• Was the temperature high enough to melt all of the parent rock, or was only partial melting of minerals on the low end of Bowen's reaction series achieved?
• Amount of mixing of the cooling crystals.
• As crystals formed, did they continue to mix and react with the magma, or were some of the earlier formed crystals segregated from the magma so that they could not react with it (fractional crystallization)?

VII. Classification of (names for) igneous rocks - 

VIII. Possible essay questions -  

• Describe the origin and texture of intrusive igneous rocks.
• Describe the origin and texture of extrusive igneous rocks.
• Describe and illustrate Bowen's reaction series.
• What are the three factors that govern the composition of a magma?
• Describe and draw a chart that illustrates the classification of igneous rocks.