1 Trilobite Hunter, Part 1 Introduction to the Grand Canyon Earth History, Investigation 8

2 Rock Hunt Imagine you are on a field trip to a local quarry with your school. The teacher asks everybody to find the coolest rock they can and bring it back to him. You and your friend go to opposite sides of the quarry. You both find rocks at the same time and you wave to each other.

3 You bring back a grey rock with marks on it that look like a picture of a bug. Your friend brings back a weird rock that hardly weighs anything and is full of tiny holes. Two Rocks

4 Your teacher says,“That’s a trilobite fossil. You can sell that on the internet for a lot of money.” Your friend says, “I want one too. Where should I look?” Trilobite Fossil The teacher answers, “If you want to find fossils, you have to know how rocks form and what kinds of rock have fossils in them.”

5 Throughout this module, see if you can figure out the answers to these questions: EH Questions What kinds of rocks are likely to contain fossils? Where should you look for trilobite fossils?

6 There are some places where it's easy to find lots of different kinds of rocks. The tallest mountains and deepest canyons are both great places to look. The Grand Canyon is a really great place to look, because you can see rock layers there that represent millions of years of Earth's history. Where to Look

7 Your friend's rock is called pumice. Pumice Let’s go find some pumice in the Grand Canyon and see if we can figure out why your friend's rock doesn't have a trilobite fossil.

Compare Rock Types8 Contrasting Case Activity 1, Part 1 Earth History, Investigation 8

Compare Rock Types9 Venn Diagram Similarities. Rocks of the same type have some things in common. Differences. Rocks of the same type can also be different from each other. These things are only true about the first rock These things are true about both rocks These things are only true about the second rock

Compare Rock Types10 How to use a Hand Lens Hold the hand lens so the big circle is very close to your eye. Bring the rock closer and closer to the lens until it pops into focus. Try the same thing with the smaller circles. The magnification is stronger, but you can only see part of the rock at a time. Holding the lens close to your eye will take full advantage of its magnifying power. What does this word mean?

Compare Rock Types11 List Observable Features What do the rocks look like? How do they feel? Create a table in your lab notebook and list the features you can observe about the two igneous rock samples. Igneous #11 Igneous #17

Compare Rock Types12 Which is Which? Can you figure out which rock is granite and which is pumice? 11 17

11 17 Compare Rock Types13 What’s the same? Look at the two cards. Are any of the points exactly the same for both rocks? How would you show this in the diagram?

Compare Rock Types14 Igneous Granite Only Both Granite & Pumice Pumice Only Formed when molten rock cools and hardens

11 17 Compare Rock Types15 What else is the same? Are any of the points partly the same for both rocks? How would you show this in the diagram?

Compare Rock Types16 Igneous Granite Only Both Granite & Pumice Pumice Only Formed when molten rock cools and hardens Rough and dull

Compare Rock Types17 What is different? Identify one thing that is true about granite but not about pumice. How would you show this in the diagram? 11 17

Compare Rock Types18 Igneous Granite Only Both Granite & Pumice Pumice Only Made of minerals Formed when molten rock cools and hardens Rough and dull It is hard and has shiny, smooth crystals Most grains are coarse Usually fairly light in color Formed deep beneath Earth’s surface

Compare Rock Types19 What else is different? Identify one thing that is true about pumice but not about granite. How would you show this in the diagram? 11 17

Compare Rock Types20 Igneous Granite Only Both Granite & Pumice Pumice Only Grain size is fine to medium Contains a lot of small air pockets Usually feels lighter than other rocks of its size Formed on Earth’s surface from molten rock released by a volcano Made of minerals Formed when molten rock cools and hardens Rough and dull It is hard and has shiny, smooth crystals Most grains are coarse Usually fairly light in color Formed deep beneath Earth’s surface Made of volcanic glass