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Rock Classification Hands-on STEM Lesson Plan

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I am a Christian. I was an 8th-grade American History teacher. I am currently a freelance writer, public speaker, & homeschooling mom of 9.

Hands-on Rock Classification Lesson Plan

Hands-on Rock Classification Lesson Plan

This is part 2 of a 6 part hands-on unit on Earth Science from a Christian perspective. Make and eat "sedimentary" Seven Layer Bars, create "metamorphic" Snickers bars, do some rock mining, and more! My lessons are geared toward 2nd-3rd grade level children and their siblings. I created these lessons to do with a weekly homeschool co-op. We meet each week for 2 1/2 hours and have 14 children between the ages of 0-12. Use these fun lessons with your classroom, family, camp, after school program, or co-op!

Introduction to Rocks

1) Discuss Psalm 18:1-3.

2) Ask what we learned about last week. Who can name the main 4 layers of the earth? Who can name one type of soil? How do geologists find out about what is under the ground?

3) Today we are going to study about rocks. Read a book on rocks: Jump into Science: Rocks and Minerals by Steve Tomecek (skipping the page about the Big Bang theory).

YOU WILL NEED: Jump into Science: Rocks and Minerals by Steve Tomecek or other book introducing rocks

Book to read for activity 3

Introduction & Sand and Soil

Different colors and textures of sand

Different colors and textures of sand

4) Show different colors and textures of sand/soil and review what makes them look different. Briefly discuss 3 forms of rocks and how they are each formed. Say something such as:

  • Why do chocolate chip cookies, oatmeal cookies with raisins, and sugar cookies with colored sprinkles all look different? They have different ingredients. That's why sand and rocks look different. They are made up of different minerals. If I laid out a plate of cookies that had chocolate chip, oatmeal, and sugar cookies all mixed up, and you wanted to put them into those 3 types, how would you be able to easily tell them apart? Yes, just by looking at their appearance. That's also how scientists divided up animals into phyla. That's not how geologists, who are scientists who study rocks, divide up rocks, though.
  • Geologists (have the kids say “geologists”) don’t divide rocks into groups by what they look like. They divide them by how they are made. Did you know that rocks were actually created and are still getting created even today?
  • The most common type of rock is called igneous rocks. They are created by extreme heat under the earth's surface and can be tossed out of a volcano. How are igneous rocks made? (Have the children wipe their foreheads for heat as they repeat “heat” and make a cone shape with their hands over their heads for volcano as they say, "tossed out of a volcano.")
  • Sedimentary rocks are usually made from water and pressure. You'll have layers of sand, shells and mud, fossils and mud, harden on top of each other. How are sedimentary rocks usually made? (Have the children wiggle their hands and arms like waves as they say, "Water.")
  • The third type of rock is when heat and pressure are applied to an igneous or sedimentary rock. Geologists call those rocks metamorphic rocks because "metamorphic" means "changed" and these rocks have changed. What caused them to change? (Have the children wipe their foreheads for heat and slap their hands together and press their palms together for pressure as they say, "Heat and pressure.")

YOU WILL NEED: different colors and textures of sand/soil

The Rock Cycle Song

Rock Cycle Song

Rock Cycle Song

5) Sing The Rock Cycle Song. Tune: Row, Row, Row Your Boat

SED-I-MEN-TARY rock
Has been formed in layers
Often found near water sources
With fossils from decayers.

Then there's IGNEOUS rock
Pumice, Obsidian, Granite
Molten Lava, cooled and hardened
That's how God planned it.

These two types of rocks
Can also be transformed
With pressure, heat and chemicals
METAMORPHIC rock is born.

  • Hand motions for sedimentary rock lines: continuously put one hand on top of the other
  • Hand motions for igneous rock lines: Hold arms in a cone shape over your head. Hold up your fingers and wiggle them as your arms go out in circles to show the lava pouring out of the volcano. When your hands circle back in front of your chest, make fists to show the lava hardening.
  • Hand motions for metamorphic rock lines: hold out both hands and then clasp both hands together for pressure

YOU WILL NEED: Words to song printed on large piece of paper

Starburst Rock Activity Option (if you have limited time)

Starburst "Rocks"

Starburst "Rocks"

*I've taught this lesson plan many times.

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  • When we have 2 hours or more, I teach the full lesson, making Sedimentary Seven Layer Bars, Igneous Lollipops, and Metamorphic Snickers.
  • When I teach a 45 minute class, we do the below Starburst Candy activity.

Sedimentary Rocks: Seven Layer Bars

Sedimentary Seven Layer Bars

Sedimentary Seven Layer Bars

6) Make Sedimentary Seven Layer Bars.

  • Explanation: These bars are like sedimentary rocks because they are made in layers. Sedimentary rock is made from layers of mud, sand, or even seashells that get built up during huge floods. Can anyone think of a time when there was a huge flood that covered the entire Earth? Yes, the one during the time of Noah. All those layers of mud, rocks, and other items got squeezed and stuck together to make new rocks. This cookie is made in layers and you'll still be able to see the layers even after it is pressed together and cooked. We'll pretend like the butter is water and the graham cracker crumbs are sand. They get pressed into one layer. They butterscotch chips, chocolate chips, coconut, and nuts are like shells and dead animals that got buried in the flood. The sweetened condensed milk will be like more water and mud that covers up all the layers of shells and dead animals.
  • Divide children into 2 groups. Have each group make the below recipe. Give each child an ingredient to add. As the children add each layer of the bars, remind them of what was said in the explanation above.
  • After children have assembled their Sedimentary Rock Seven Layer Bars and are ready to put them in the oven, tell them that we are now going to add the element of heat. When you use heat, pressure, and/or chemicals, a sedimentary rock CHANGES into what type of rock? Metamorphic rock! After we bake our Sedimentary Rock Seven Layer Bars, they will change into Metamorphic Multi-layered Bars.

Sedimentary Rock Seven Layer Bars:
1/2 cup butter, melted in the baking dish ahead of time
1 1/2 cups graham cracker crumbs
3/4 cup butterscotch chips
1/2 cup miniature semi-sweet chocolate chips or 3/4 semi-sweet chocolate chips
1 cup flaked coconut
1 cup nuts (pecans or walnuts), chopped
1 (14 ounce) can sweetened condensed milk
Preheat oven to 350°F. In the 13x9 inch casserole dish, melt the butter in the microwave. Let a child add the graham cracker crumbs combine it with the butter. Have a child use the mixing spoon to press the crumb mixture firmly on the bottom of the pan. Have children evenly sprinkle the next ingredients in order over the graham cracker layer: butterscotch chips, chocolate chips, coconut, and nuts. Let a child pour the sweetened condensed milk evenly over the bars. Bake 25 minutes or until lightly browned. Put in the freezer after they come out of the oven so they'll cool faster.

YOU WILL NEED PER GROUP: 1 1/2 cups graham cracker crumbs, 1/2 cup butter or margarine, 3/4 cup butterscotch chips, 1/2 cup miniature semi-sweet chocolate chips, 1 cup flaked coconut, 1 cup chopped nuts, 1 (14 ounce) can sweetened condensed milk, 9x13 baking pan, mixing spoon, & measuring cups

Studying Sedimentary Rock Properties

Limestone dissolving in vinegar

Limestone dissolving in vinegar

7) Using magnifying glasses, look at sedimentary rocks & discuss characteristics:

  • In order to make sedimentary rock, you need water and pressure. Hold your hands high and wiggle your fingers down to look like rain. Sedimentary rock is made from water and pressure.
  • [Show a piece of limestone with a shell imprint on it or a picture of one.] You'll have layers of sand, shells and mud, or fossils and mud, harden on top of each other. Most sedimentary rock was formed from the mud and plants and animals that squished together under the mud and water during Noah's Flood. That's why you can find fossils in some types of sedimentary rock.
  • [Show a piece of conglomerate or breccia or a picture of one.] Even though sedimentary rock is usually formed in layers, some rocks that have obvious layers in them are actually metamorphic rocks, not sedimentary rocks. Many sedimentary rocks are frequently crumbly (like limestone and sandstone) or they're made up of lots of shells or crystals and "cemented" together like conglomerates or breccia. In this piece of conglomerate, the sediment, pebbles, and other size rocks were cemented together by minerals from water.
  • Sedimentary rocks are sometimes crumbly. A sedimentary rock contains a lot of little pieces of weathered rock all layered, smashed, and glued together doesn’t it? Suppose that water, ice, or wind kept running past that rock. What do you think would happen after a while? Yes, little pieces would fall off. We call that weathering and erosion. Sometimes it happens slowly. If a big rock smashed down on top of a little rock, it could happen quickly.
  • If you have examples of sedimentary rocks, pass them around. Examples of sedimentary rock include limestone, flint, rock salt, conglomerate, breccia, shale, and others. The kids loved getting to see a piece of limestone with a shell imprint on it.
  • Before we move on to the next time of rock, tell me what you need to make sedimentary rock. (water and pressure) Let's wiggle our fingers like water from rain one more time.

YOU WILL NEED: Sedimentary rocks (limestone, flint, rock salt, conglomerate, breccia, and/or shale) and a piece of limestone with a shell imprint on it (optional) & magnifying glasses

8) Limestone Erosion (*NOTE: If using this lesson as part of the Earth Science unit study, do this activity during the Erosion study instead of this lesson.)

  • Drop a piece of granite or other rock in a small cup of vinegar and have the children tell you what happens. (Nothing will happen.)
  • Give each child a small cup of vinegar and a small piece of limestone. Have them drop the piece of limestone in the vinegar. Ask the children what they see. (It will effervesce and a small amount of heat will be produced.)
  • Ask what they think would happen to the limestone rock if we left it in that vinegar for a few months. (It would “disappear.”)
  • Quickly explain they just caused a chemical reaction by combining an acid (vinegar) with a base (limestone).
  • Ask if anyone has seen a sinkhole. Under the ground where we live here in Florida, there is lots of limestone. When it rains, the rainwater mixes with materials in the ground that add some acids to it. As the rainwater sinks deep into the ground where the limestone is, this is what happens. The slightly acidic rainwater erodes away the limestone. If we left this limestone rock in the vinegar for a long time, it would “disappear.”
  • The same thing happens with the limestone under the ground. If it’s a thin enough layer, it will erode and eventually break open and cause a sinkhole.

YOU WILL NEED PER CHILD OR GROUP: small rock that isn’t limestone, small cup of water, small cup of vinegar, & small piece of limestone

Igneous Rock Lollipops

Igneous Rock Lollipops

Igneous Rock Lollipops

9) Make "Igneous Rock" Lollipops. (*An adult or teacher will stay & stir after everyone combines the ingredients.)

  • Explanation: When rocks get incredibly hot, they melt. Lava is hot melted rock. Does anyone know where lava comes from? Yes, it comes out of a volcano. When molten lava comes out from the Earth's mantle through a volcano, it cools and the rock hardens into smooth obsidian rock. The same thing is going to happen to this candy mixture. I'm going to start heating this up. When I heat it up, what will happen? Yes, it will melt. Eventually I'm going to get it very hot and then I'm going to take it off the stove and let it cool. What do you think will happen to it then? Do you think it will stay a liquid? We'll find out.
  • Have one child 1 cup of corn syrup and let them pour it into a saucepan.
  • Have one child drop 1/4 stick (4 Tbsp.) of butter into the saucepan.
  • Ahead of time measure out 2 cups of sugar and put in a bowl or bag. Allow the remaining children to each put a spoonful of sugar into the saucepan.
  • Ask, “What is going to happen to all of this when I start to heat it? Yes, it will melt and become liquid.
  • Put it on the stove and heat it according to the below directions. Finish making the lollipops yourself by following the directions below:

Igneous Rock Lollipop Recipe:
2 cups sugar
1 cup light corn syrup
4 tablespoons butter
2 (1/3 ounce) boxes of flavored gelatin
lollipop sticks
nonstick cooking spray
Cover cookie sheet with nonstick spray and place the lollipop sticks on sheet with one end sticking off the edge and leaving room to pour the liquid candy onto the other end. Combine the sugar, corn syrup and butter in a saucepan over low heat and cook until the sugar is dissolved. Slowly bring to a boil stirring frequently. Cook for 7 minutes or until a candy thermometer reads 275 degrees. Stir in packet of gelatin and continue stirring until smooth. Remove from heat and quickly spoon mixture onto one end of the sticks and cool. Put in the freezer after pouring them so they'll harden faster.

YOU WILL NEED: 2 cups sugar (premeasured in a bowl or bag), 1 cup light corn syrup, 4 tablespoons butter, 2 (1/3 ounce) boxes of cherry or other flavored jell-o [not prepared jell-o], 2 baking sheets, non-stick cooking spray, candy thermometer, mixing spoon, 16 lollipop sticks, saucepan, 16 sandwich baggies for taking them home

Studying Igneous Rock Properties

Pumice floating in water while obsidian sinks

Pumice floating in water while obsidian sinks

10) Look at igneous rocks & discuss characteristics:

  • The most common type of rock on the earth is called igneous rocks. They are created by extreme heat under the earth's surface and can be tossed out of a volcano. How are igneous rocks made? Wipe your forehead with your right arm, and now wipe it with your left arm. It's extreme heat. Now make a cone shape with their hands over your heads to look like a volcano because they're sometimes tossed out of a volcano.
  • The word Igneous comes from the Latin word ignis which means fire. Some igneous rocks are melted rock that is magma or lava. When it cools and hardens, it becomes igneous rock. Igneous rocks are sometimes glassy or have crystals in them.
  • When magma cools slowly below the surface, the igneous rock formed may have large crystals, which are very easy to see. If you see a rock with sparkles like this piece of granite, it is probably an igneous rock. Other igneous rocks form on the Earth’s surface and cool more quickly. Their crystals are usually extremely small. Igneous rocks are usually not layered. They may have air holes in them like this piece of pumice, or they may be glass-like like this piece of obsidian.
  • If you have examples of igneous rocks, you can pass them around. Examples of metamorphic rock include granite, obsidian, pumice, basalt, diorite, scoria, and others.

YOU WILL NEED: Igneous rocks (obsidian, pumice, basalt, diorite, scoria, and/or granite) & magnifying glasses (brought by families)

11) The only rock that floats.

  • Ask the children if they think rocks sink or float.
  • Hold up a piece of obsidian, which is hardened lava from a volcano. As the children pass it around, have them hypothesize, will it sink or float? Have one of the children carefully drop it in a bowl of water. "Was your hypothesis correct?"
  • Hold up a piece of pumice, which is also hardened lava from a volcano. As the children pass it around, have them hypothesize, will it sink or float? Have one of the children carefully drop it in a bowl of water. "Was your hypothesis correct?"
  • Ask, "If those both are hardened lava, why do you think one sinks and one floats?" Obsidian and pumice are both formed when lava comes out of a volcano. If water mixes in with the super hot molten lava, then gas/bubbles will form. The rock will cool so quickly that the gas doesn't have a chance to escape, so the pumice stone is filled with holes. It's not as dense as obsidian or as most other rocks, so it floats.

YOU WILL NEED: obsidian & pumice and a large bowl of water

Metamorphic Rocks Snickers Demo & Properties

Metamorphic Snickers Demo

Metamorphic Snickers Demo

12) Metamorphic Snickers Demo.

  • Give each child a bag containing the half of the Snickers bar. Tell them to pretend that this is a sedimentary rock. Have them notice the different layers.
  • Have the children put the bagged candy bar on the floor and then put a book on top of the candy bar (to more evenly divide the pressure). Have each child step on the book to smash the Snicker's bar. Tell them they are providing heat and strong pressure to their sedimentary rock. Ask them what they think their Snickers bars will look like. Will they still be able to see each of the individual layers?
  • Have them remove the book. Can they see those distinct layers anymore? No. The same thing happens with metamorphic rocks. Heat and pressure make sedimentary or igneous rocks into a metamorphic rocks. Have them repeat “heat and pressure.”
  • Save the candy so they can eat it if desired at a later time.

YOU WILL NEED PER CHILD: snack size Snicker's candy bars cut in half with each half placed in a sandwich or snack sized ziplock bag & a book

13) Look at metamorphic rocks & discuss characteristics:

  • When heat and pressure are applied to a sedimentary or igneous rock, it changes into metamorphic rock. "Metamorphic" means "changed" and these rocks have changed. What caused them to change? (Heat and pressure) Wipe your foreheads for heat and push your hands together for pressure. Now say, "Heat and pressure."
  • If you have examples of metamorphic rocks, you can pass them around. Examples of metamorphic rock include marble, quartzite, slate, soapstone, gneiss, garnet schist, and others.
  • Pressure comes from the layers of rock that press down on layers below them. Metamorphic rocks may have crystals or layers because they are formed from other rocks. Some common metamorphic rocks are marble, gneiss (pronounced “nice”), and schist ("shist").
  • [Show a piece of marble or a picture of marble.] This piece of marble is a large crystal rock formed from this piece of limestone. (Pass them around and let the children feel the differences.) Marble comes in lots of different colors. Does anyone have marble counter tops in their kitchen? What color are they? Its color depends on the presence of different minerals.
  • Show the 3 sets of pictures from Let's Go Rock Collecting by Roma Gans comparing the sedimentary or igneous rock and the metamorphic rock it becomes.

YOU WILL NEED: magnifying glasses, metamorphic rocks (gneiss, marble, quartzite, slate, soapstone, and/or garnet schist), limestone, and Let's Go Rock Collecting by Roma Gans

Book to use for activity 15

Sedimentary Seven Layer Snack

Sedimentary Seven Layer Bar Cookies

Sedimentary Seven Layer Bar Cookies

14) Let the children eat the Seven Layer Bars and drink water.

  • Tell the children they're drinking water to remind them that sedimentary rocks are usually formed by water.
  • Also note that the Sedimentary Sever Layer Bars are kind of soft and crumbly. Sedimentary rocks can sometimes be soft and crumbly too.
  • While children eat, divide up lollipops and remaining bars for children to take home.

YOU WILL NEED: a knife for cutting bars, cups for water, napkins, & snack sized baggies

Geodes

Breaking open geodes

Breaking open geodes

15) While children are finishing Seven Layer Bars, talk about and show geodes.

  • Talk about God choosing the ugly, poor, unworthy, etc. of this world (I Corinthians 1:27-31) and making us into beautiful creations - sometimes using difficult circumstances to create us into the beautiful creation He wants us to be.
  • Go outside. Give each child a geode, and tell them to put it inside their sock. Have them smash open their geodes using their hammers. They can put their geode pieces in a snack sized baggie.
  • Tell them that geodes are usually sphere shaped and contain pretty quartz crystals. Not all of these rocks will have crystals in them. The only way to find out if they do have them is to break them open.
  • Geodes can be found in either be sedimentary (dolomite) or igneous (lava) rocks.

YOU WILL NEED PER CHILD: a hammer & sock (one per child or per group) & a geode (The first time I did this lesson I purchased a box of 20 geodes off e-bay for $20 including postage. They were great! The second time I did this lesson, I purchased the box of 10 geodes "Break Your Own Geodes" by GeoCentral from amazon.com. These were solid inside. The children still enjoyed them as they had something white inside, but they were not as nice as the ones that had hollow middles with crystals.)

Rock Collecting & Mining

Rock Show and Tell

Rock Show and Tell

Rock mining with seeded dirt.

Rock mining with seeded dirt.

16) Rock Show & Tell: Allow children who want to show the rock they brought show them to the group. They can share a little bit about their rock.
YOU WILL NEED: rocks brought by children

17) Rock Mining/Collecting: 3 OPTIONS:

  • Option 1: Sift some dirt with stones in it (gem mining dirt). Put a scoop of dirt in each of their colanders and let them use a hose or dip it in buckets of water to wash off the dirt. (You can purchase gem mining dirt on e-bay, though we bought ours for $25 at a ruby mine in North Carolina.)
  • Option 2: Go outside & search for rocks.
  • Option 3: Collect some rocks ahead of time and toss them around in some dirt or some cheap stones. If using dirt, put a scoop of dirt in each of their colanders and let them use a hose or dip it in buckets of water to wash off the dirt. If using stones, simply allow them to sort through the bag of stones to find pretty ones.

-Identify them as you are able. Then let each child select one from their collection and describe it: rough, gray, dull, sparkly, smooth, pink, etc.

YOU WILL NEED: Gem mining dirt (optional) & grocery store plastic bags or lunch paper sacks (for holding rocks/gems)

18) Five minute review of what we learned. Ask questions such as: What kind of scientist studies rocks? (geologist) Do geologists divide rocks by how they look? (No.) How do they organize and group them? (By how they were made.) Name one type of rock. Name another. What is the 3rd type? (Sedimentary, Igneous, Metamorphic) How are sedimentary rocks formed? Igneous? Metamorphic? What was your favorite activity from today?

These are the rest of our favorite books to read on rocks (most of which need slight editing if you would prefer to present a Christian worldview):

Are you looking for Christian options?

  • Thank God for Rocks by Esther Bender is a sweet Christian picture book about a farmer who thanks God for the rocks in his field and uses them to make walls, his home, etc.
  • Dry Bones and Other Fossils by Gary E. Parker is a wonderful children's picture book that presents the creation of rocks and fossils from a Christian worldview.
Activity from Lesson 5 on earthquakes

Activity from Lesson 5 on earthquakes

Make an edible model of the earth as you study the Earth's layers, bake cookies that demonstrate how sedimentary, metamorphic, and igneous rocks form, create fossil casts, build marshmallow structures that can withstand a jell-o earthquake, carve gullies and valleys in sand using wind, water, and ice, make presentations on various aspects of the Earth, and more during this 6 lesson hands-on unit study of Earth Science!

  • Earth's Layers and Soil Composition Lesson - This is part 1 of a 6 part hands-on unit on Earth Science from a Christian perspective. Make an edible model of the earth, act out each of the Earth's layers, do core testing on a cupcake, make oobleck, and more!
  • Rock Classification Lesson - This is part 2 of a 6 part hands-on unit on Earth Science from a Christian perspective. Make and eat "Sedimentary" Seven Layer Bars, create "Metamorphic" Snickers bars, do some rock mining, and more!
  • Fossils Lesson - This is part 3 of a 6 part hands-on unit on Earth Science from a Christian perspective. The focus of this lesson is fossils! Create fossils casts, dig up and piece together dinosaur skeletons, excavate dinosaurs, eat edible ammonites, and more!
  • Plate Tectonics and Volcanoes Lesson - This is part 4 of a 6 part hands-on unit study on Earth Science. Make edible volcanoes, build an erupting ring of fire, demonstrate plate tectonics using graham crackers, form each type of volcano using play-doh, and more!
  • Earthquakes Lesson - This is part 5 of a 6 part hands-on unit study on Earth Science. Create a tsunami, build marshmallow structures that can withstand an earthquake, act out seismic waves, build and use a seismograph, and more!
  • Erosion Lesson - This is part 6 of a 6 part hands-on unit study on Earth Science. Demonstrate various types of erosion as children carve gullies and valleys in sand using air, water, and ice. Re-create the Grand Canyon. Compare how soil resists erosion.
  • Earth Science Presentation and Field Trip Ideas - This is the culminating project we did after a 6 part hands-on unit on Earth Science. We made edible volcanoes, performed earth science demonstrations, displayed paintings of the earth's layers and volcanoes, sang songs about the earth science, and more! Also included are the field trips we attended during this unit.