Teach kids to identify rock layers from oldest to youngest. First, help them understand the properties and types of rocks. Second, explore fossils. Finally, put the two together to analyze layers of earth and uncover their history.
Ms. Sneed Prepares to Teach Rock Layers from Oldest to Youngest
Our favorite fourth grade teacher sat at the side table with her teaching partner. “This year in earth science,” she said, “I want my class to confidently order rock layers from oldest to youngest.”
“Hmm,” Mr. Frank responded. “In the past, we’ve completed a few worksheets on this. Unfortunately, the concept didn’t seem to stick.”
Ms. Sneed tapped her pencil on the table, deep in thought. “No pun intended, but I think we need to dig deeper. You know, provide more background information and scaffold students to understanding.”
Her teaching partner nodded. “Agreed. Certainly we’ll have to teach sedimentary rocks and fossils. What else?”
As Ms. Sneed headed toward her file cabinet, she responded. “I say we begin at the beginning. First, our kids need to know what a rock is. Then they must understand the three main types of rocks. Of course, they should also explore fossils.”
After she retrieved a file, she returned to the table.
Rock, Mineral, or Neither?
“Years ago,” she said, “we covered rocks more thoroughly.
She pulled out two oblong sheets. “After reading about rocks, they use these checklists to determine if a substance is rock, mineral, or neither.”
Mr. Frank studied the checklists.
A mineral:
- occurs in nature
- has never been alive
- is solid
- has a specific chemical composition
- has a specific structure
A rock:
- occurs in nature
- has never been alive
- is solid
- is made of minerals
“Ah, I see. This helps kids define rocks. It’s a good first step. I love the way it integrates critical thinking with science.”
Teaching Rocks – Igneous, Sedimentary, and Metamorphic
“Next, I’d like my students to know the three types of rocks: igneous, sedimentary, and metamorphic. This will help them understand that we generally order sedimentary rock layers from oldest to youngest.”
She pulled out an anchor chart that illustrated the rock cycle.
Now Ms. Sneed opened her laptop and clicked around. Then she turned it toward Mr. Frank and pointed to a video. “Geology Kitchen: The Three Types of Rocks” has a fun, lively format. After eight minutes, they have a pretty good understanding of igneous, sedimentary, and metamorphic rocks.”
Next, she clicked over to Rock Cycle from Annenberg Learner Interactives.
“Cool!” Mr. Frank exclaimed. “An interactive learning experience.”
“Yep, this website will seal the deal. It even has a quiz at the end.”
“Tomorrow,” says Ms. Sneed, “we’ll start identifying rocks. Please find five or more rocks around your neighborhood tonight. Bring them in tomorrow, and we’ll see if we can figure out what they are.”
Identifying Minerals in Rocks
Ms. Sneed shuffled through the file again. Then she pulled out two more pages. “What do you think about a little rock identification?”
“Yes, I’d love to! Working with actual rocks will get kids excited about our unit. We can tell them to bring some from home.”
“Right. In my opinion, actual identification is not necessary. Sure, I’d like kids to use multiple resources and critical thinking. But accuracy is not a priority. Here’s how I hope it will go:
- Child 1: That one has to be sedimentary. See how there are little pieces of shell in it?
- Child 2: I know it’s sedimentary because it’s in layers.
- Child 1: Wait a minute. Other types of rocks can have layers too. Remember how the video said that some metamorphic rocks are layered?
- Child 3: Isn’t this one pretty? I like those pink and gray crystals.
- Child 2: Crystals? Doesn’t that mean it’s igneous?
- Child 1: Hey! I know that rock. Rocks with that kind of crystals are called granite.”
Mr. Frank grinned at Ms. Sneed’s performance. Then he nodded. “Exactly. It’s all about the experience.”
Fossils
“Next,” Ms. Sneed continued, “we’ll introduce fossils.” Again, she clicked around on her laptop. “First, we can show this short video, What’s a Fossil? It’s less than three minutes long and provides a great introduction.”
Slowly, an impish grin spread across her face. “And then we can play my all-time favorite teaching video. Oh wow, I can’t wait to use this again!”
The tune for “Party Rock Anthem” filled the room as Ms. Sneed played “Fossil Rock Anthem” for Mr. Frank.
“Awesome! Our kids will go crazy!”
“Of course, we’ll have to get a little more serious as we explain fossils and how they help us order rock layers from oldest to youngest,” said Ms. Sneed. Again, she pulled out some papers.
Ordering Rock Layers from Oldest to Youngest
Finally, Ms. Sneed pulled out one more worksheet. “After all of that, our students will be ready to order rock layers. On this worksheet, they must list the layers from earliest to present day. Then they list organisms found in each and determine if the habitat was on land or in the water.”
“Perfect,” said Mr. Frank. “We can use this as a grand finale.”
Enjoy Teaching Rocks
As Ms. Sneed sorted through the pages, her teaching partner jotted down some rough lesson plans. “In a short amount of time,” Mr. Frank said, “we can teach the basics of rocks and minerals, as well as how to identify rock layers from oldest to youngest.”
