1. Rocks: The Tour Guide to Natural History

2. Rocks Rocks are like nature’s history book. Every rock, no matter how big or small it is, has a story to tell. This powerpoint will serve as an introduction to rocks and will get your ready to learn about rocks in greater detail.

3. What is a rock? A rock is defined as a mixture of minerals, volcanic glass, organic matter, or other materials. Organic = Derived from living matter Minerals that make rocks are called rock-forming minerals.

4. The Rock Cycle To track the processes that cause rocks to change, scientists created a model called The Rock Cycle. The Rock Cycle is a model that shows how rocks slowly change from one form to another through time. There are three types of rocks—igneous, sedimentary, and metamorphic, and the rock cycle shows how these rocks form and change.

5. The Three Types of Rocks Igneous: Formed from the cooling and solidification of molten magma. Sedimentary: Rock formed from consolidated sediments. Metamorphic: Rock that was once another type of rock but changed through heat or pressure.

6. The Rock Cycle

7. The Rock Cycle 2 Rocks change by many processes. Sedimentary rocks can change by heat and pressure to become metamorphic rocks. The metamorphic rock can then melt and later cool to form an igneous rock. The igneous rock could then be broken into fragments by weathering and erode away. The fragments might later compact and join together to form another sedimentary rock. Any rock can change into any other type of rock. Also one rock can change into another rock of the same type. How many paths can you see through the rock cycle?

8. The Rock Cycle

9. Matter and the Rock Cycle The rock cycle shows how rock can be weathered to small rock and mineral grains. This material can then be eroded and carried away by wind, water, or ice. These materials are not destroyed or lost from the cycle. This follows the principles of the Law of Conservation of Matter. Law of Conservation of Matter: Matter can never be created or destroyed, only changed in forms. The elements from the rocks are redistributed in other forms.

10. James Hutton James Hutton was a Scottish physician and naturalist. In 1788, he first recognized that rocks undergo profound changes. At Siccar Point (right), he noticed that layers of solid rock had been altered since they formed. Some of the layers were horizontal in their layout, and some were tilted more vertically. Hutton published these observations, which proved that rocks are constantly changing. Today, over 200 years later, geologists are still influenced by his work.