1. Daily Warm-Up Exercises
Day 3
What’s the same and different about sand, silt, and clay? (Use page 132 of EH Resource Book)
They are all made up of a lot of small grains, but the size of the grains is different. Silt has much finer grains than sand, and clay’s are very, very fine.
What are grains?
the particles that make up a rock
You might have students look at the Wentworth scale on page 35 of the resources book. It shows that sand can range from very coarse to very fine, and that silt and then clay are at the smallest end of the scale.
Daily Warm-Up Exercises 1
Compare Rock Types, Part 3
Daily Warm-Up Exercises 1

2. Contrasting Case Activity 1, Part 3 Earth History, Investigation 8
Compare Rock Types
Contrasting Case Activity 1, Part 3
Earth History, Investigation 8
In today’s activity, students will use their Venn diagrams from Days 1 and 2 to compare all three rock types.
Materials needed:
•rock samples 11 & 17; 1 & 18; 7 & 8
•hand lenses
•rock description cards (worksheets 1-3)
•Venn diagrams (worksheets 4-7)
Compare Rock Types 2
Compare Rock Types, Part 3 2

3. Conclusions about Igneous Rocks
What features are shared by both igneous rocks?
Granite Only
Both Granite & Pumice
Pumice Only
It is hard and has shiny, smooth crystals
Usually feels lighter than other rocks of its size
Formed when molten rock cools and hardens
Grain size is fine to medium
Most grains are coarse
Rough and dull
Contains a lot of small air pockets
Usually fairly light in color
Made of volcanic glass
Made of minerals
Formed deep beneath Earth’s surface
The rectangle and arrow will appear on keypress. Emphasize that these conclusions are tentative because they are based on only two samples.
Formed on Earth’s surface from molten rock released by a volcano
Compare Rock Types 3
Compare Rock Types, Part 3 3

4. Conclusions about Metamorphic Rocks
What features are shared by both metamorphic rocks?
Schist Only
Both Schist & Quartzite
Quartzite Only
Fairly shiny
Rough
Dull, and hard
Medium to coarse grain size
Made of minerals
Fine grain size
Formed when a rock changes due to heat and/or pressure
Grains appear to be fused together
Crystals are flat and arranged in layers
Formed deep beneath Earth’s surface
Formed from slate, a metamorphic rock
The rectangle and arrow will appear on keypress. Emphasize that these conclusions are tentative because they are based on only two samples.
Formed from sandstone, a sedimentary rock
Compare Rock Types 4
Compare Rock Types, Part 3 4

5. Conclusions about Sedimentary Rocks
What features are shared by both sedimentary rocks?
Shale Only
Both Shale & Sandstone
Sandstone Only
Dull and hard
Smooth
Rough
May contain fossils
Very fine grain size
Made of minerals
Medium to coarse grain size
Grains are arranged in layers
Formed when something gets compacted and cemented together
Formed from particles of silt or clay
Formed from grains of sand
The rectangle and arrow will appear on keypress. Emphasize that these conclusions are tentative because they are based on only two samples.
May form on or below Earth’s surface
Compare Rock Types 5
Compare Rock Types, Part 3 5

6. Compare Rock Types
Look at the center sections of all three diagrams. Is there anything that all three rock types have in common? no
Is there anything that two of the three rock types have in common?
Metamorphic and sedimentary rocks are both made of minerals.
You may need to offer some hints to help students focus on what the rocks are made of.
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Compare Rock Types, Part 3 6

7. Compare Rock Types
Look at the igneous diagram. Is either of these rocks made of minerals?
granite is; pumice is not
What can we conclude from this?
Most rocks are made of minerals.
Look at the last Venn diagram. This one has three circles, one for each rock type. How would you show that most rocks are made of minerals?
The next slide shows how to depict this information.
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Compare Rock Types, Part 3 7

8. Rock Types Most rocks are made of minerals Igneous Metamorphic
Sedimentary
Most rocks are made of
minerals
A feature that is common to all three rock types goes in the center, where all three ovals overlap. 8
Compare Rock Types
Compare Rock Types, Part 3 8

9. Compare Rock Types
Is there anything else that is true about two rock types but not true about the third?
Igneous and sedimentary rocks may form on or below Earth’s surface.
Metamorphic rocks only form below the surface.
How would you show this in the diagram?
The next slide shows how to depict this information.
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Compare Rock Types, Part 3 9

10. Rock Types Most rocks are made of minerals
Igneous
Metamorphic
Sedimentary
May form on or below Earth’s surface
Most rocks are made of
minerals
Only form below Earth’s surface
Features that are true about two types goes in the part where those two circles overlap.
Features that are only true about one type goes in the part that doesn’t overlap another circle. 10
Compare Rock Types
Compare Rock Types, Part 3 10

11. Compare Rock Types
Fill in the diagram by entering at least one feature that is true about igneous rocks only.
Do the same for metamorphic and sedimentary rocks.
The next slide shows a completed diagram for the three rock types.
Compare Rock Types 11
Compare Rock Types, Part 3 11

12. Rock Types Most rocks are made of minerals
Igneous
Form when molten rock cools & hardens
May form on or below Earth’s surface
Most rocks are made of
minerals
Only form below Earth’s surface
Form when something gets compacted & cemented together
A feature that is common to all three types goes in the center. A feature that is common to two rock types but not the third goes where those two circles overlap. A feature that is only true about one type goes in the part that doesn’t overlap another circle.
Metamorphic
Sedimentary
Form when a rock changes due to heat and/or pressure
May contain fossils 12
Compare Rock Types
Compare Rock Types, Part 3 12

13. Concluding Discussion
Based on your diagram, what do most rocks have in common?
They are made of minerals.
Suppose a previously unknown rock is discovered, and scientists categorize it as sedimentary. What can you say about this rock?
It probably formed when something got compacted and cemented together. It could have formed on or below Earth’s surface. It may contain fossils.
If we know a rock’s type, we can make guesses about it based on features of that type of rock.
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Compare Rock Types, Part 3 13

14. Concluding Discussion
Suppose they categorize the unknown rock as metamorphic. What can you say about it then?
It probably formed deep beneath Earth’s surface, when a rock changed because of heat and/or pressure.
What if they categorize it as igneous? What can you say about it then?
It probably formed when molten rock cooled and hardened. It could have formed on or below Earth’s surface.
If we know a rock’s type, we can make guesses about it based on features of that type of rock.
Compare Rock Types 14
Compare Rock Types, Part 3 14