The Three Types Of Rocks!
Students will be able to define and describe how the three major types of rocks are formed.
- Ask your students what they know about rocks. List their responses on chart paper.
- Now ask your students what they want to know about rocks. List their responses on chart paper.
Explicit Instruction/Teacher Modeling(20 minutes)
- Tell your students that there are three different kinds of rocks. The first type is called igneous. Igneous rocks are composed of melted rock that hardens and cools. A few examples include obsidian and pumice. Show your students a picture of each example.
- Explain that the second type of rock is called sedimentary, and they're formed from material that is settled into layers. The layers are squeezed until they harden into rock. A few examples include limestone, breccia, and sandstone. Show your students a picture of each example.
- Tell your students that the third type of rock is called metamorphic. These rocks are changed by heat and pressure. A few examples include slate and marble. Show your students a picture of each example.
Guided Practice/Interactive Modeling(15 minutes)
Demonstrate each type of rock using the examples below. If the hands-on materials aren't available, simply use each scenario as an analogy to help your students better understand the differences between the three kinds of rocks.
- Get an ice tray. Fill it with water and put it in the freezer. After an hour, show your students that an igneous rock is like a cube of ice. It's originally melted, then hardens after being put in the freezer. It's cool when you take it out.
- Give your students the example of an omelet for metamorphic rocks. Tell your students that the egg is mixed with various ingredients, and then cooked. The egg experiences heat and pressure from the flames of the stove, which enables it to turn into an omelet.
- Display a layered cake to your class, and tell your students that this is similar to how sedimentary rock is formed. Tell them the various layers of the cake come together after baking in the oven.
Independent Working Time(15 minutes)
- Place different types of rocks on the table. They could obsidian, pumice, sandstone, or other examples from above.
- Ask your students to identify each as igneous, sedimentary, or metamorphic.
- Ask your students to complete the All About Me: Rocks Edition worksheet.
- Ask your students to create a sandwich using construction paper. Tell them to describe igneous and metamorphic rocks on the slices of bread and sedimentary in the middle.
- Ask your students to make a graphic poster about either igneous, sedimentary, or metamorphic rocks. On the poster, they should use pictures and words to share how the rocks are formed.
Review and Closing(15 minutes)
- Post the graphic posters around the room. Give students time to walk around the room, adding sticky notes with compliments or wonders to each other's posters.
- Debrief your class about what everyone noticed about the posters. Return to the "Know" and "Want to Know" charts from the beginning of class. Ask students what they learned about rocks and write their answers on a separate piece of chart paper. Tell students that you can investigate questions that were left unanswered from the "Want to Know" section on another day.