May: Rock Talk

There are many different types of rocks that are in McHenry County. How many do you know? Become a Geologist and check out the following activities to learn more about rocks. Finish up by visiting a McHenry County Conservation District site to see how many different rocks you can find! Remember, that all rocks must stay where you find them at the conservation sites.

Check out the following activities to learn about the different kinds of rocks. Then take your knowledge outdoors and see what you can find!

Activity 1: What are the different kinds of rocks? Activity 2: Test out different rock experiments like a geologist! Activity 3: Go on a rock scavenger hunt! May Activities Rock Talk

Activity 1: What’s the difference?

Have you ever found a cool looking rock when you go out for a walk somewhere? What was so cool about it? What made you want to look at it? Did you know what kind of rock it was? Rocks can come in all shapes, colors and sizes, but all rocks belong in one of the following categories.

1. Igneous 2. Sedimentary 3. Metamorphic

How a rock gets put into one of these categories depends on how it was made. 1. Igneous rocks are formed when lava, or magma, cools, hardens, and then turns solid. Granite is one of the most common types of igneous rocks. 2. Sedimentary rocks form when layers of sediment are pressed together. Limestone is one of the most common types of sedimentary rocks. 3. Metamorphic rocks form from other rocks that have changed under heat and pressure. Marble is a common type of metamorphic rock. Now that you know the different types of rocks, you are now a Geologist! A Geologist is a scientist who studies different types of rocks and minerals. Check out the next activities to learn more about these cool rocks! Activity 2: Test it Out! Check out the following experiments and test out different rock properties. Be sure that whatever rocks you use came from a place where it’s ok to take rocks home.

Experiment: Sink or Float?

Materials needed: A container filled half way with water, 5 different rocks. Try to pick rocks that look and feel different.

 Directions: We will be testing to see if different rocks sink or float. Take a moment and make a prediction about what will happen to each rock when you put it in the water. Now take each rock one at a time and gently place them into the water. Did each rock sink or float in the water? Circle your observations below.

Rock 1: Sink or Float?

3 Rock 2: Sink or Float?

Rock 3: Sink or Float?

Rock 4: Sink or Float?

Rock 5: Sink or Float? Pumice is a type of rock that has pores throughout it and this allows this particular rock to float in water! Activity 2 Continued: Test it Out!

Limestone is the bedrock of McHenry County, which means that our county lies on a solid layer of limestone. Remember, limestone is a type of sedimentary rock, so it looks like it has layers. Limestone is usually tan or yellow in color. For our next experiment, you will need to find a piece of limestone. If you don’t have one on hand, usually some can be found at a gardening store.

Limestone Test

Materials Needed: 3 clear containers with regular distilled vinegar, a piece of limestone, 2 rocks that are not limestone.

Step 1: Fill all 3 clear containers with regular distilled white vinegar.

Limestone Step 2: Take each rock one at a time and place them into each of the clear containers. Be sure that the vinegar covers each rock.

Step 3: Wait a few minutes and make observations of any reactions or changes that you see. Write them down below. Activity 2 Continued: Test it Out!

In the space below, draw what you see each rock doing in the container of vinegar.

Limestone Rock #2 Rock #3

Did you notice that something different happened to the limestone rock in vinegar? We know that vinegar is an acid but something we might not have known is that limestone contains something called calcium carbonate. As the vinegar interacts with the calcium carbonate in the limestone, it releases carbon dioxide -- and when carbon dioxide is released in a liquid, it forms bubbles. Activity 3: Scavenger Hunt and Journal

Now take your knowledge to the outdoors! Go on a rock scavenger hunt and bring the next sheet of paper with you. As you find each rock, answer the questions on the next page!

Can You Find…?

______A rock with red colors in it

______A rock with blue colors in it

______A rock with green colors in it

______A rock with speckles of different colors in it

______A rock that has layers

______A rock with pointy/sharp edges

______A rock that is completely smooth Activity 3 Continued: Scavenger Hunt and Journal

After finding each rock on the scavenger hunt, fill out the following questions about each rock. If you would like, you can print out multiple copies of this page and dedicate each page to a single rock that you find.

 Size of the rock (small, medium, large):

 Color of the rock:

 Shape of the rock (draw a picture):

 The rock feels (cold, hard, soft, warm, etc):

Interested in learning more about rocks? Check out this book! Let’s Go Rock Collecting by Roma Gans