Tag Archives: Geology

Back Yard Geology: Crinoid Stems

There are crinoid stems everywhere; they were once so prolific they covered the bottom of the sea like a crop of wheat! The Midwest was once part of a great prehistoric sea, and where there is a sea, there are sea creatures. Where there WAS a sea, there are sea creature fossils. And limestone, which is a sedimentary rock made up, mostly, of calcium-rich fragments of ancient sea animal skeletons, specifically crinoids.

crinoid  Crinoids are often called “sea lilies” because of their resemblance to an underwater flower.  Crinoids were not plants, however; crinoids were animals.  Madeleine L’Engle wrote about farandolae in A Wind in the Door, and her character Sporos and his fellows were meant to resemble crinoids.  Literature and science!

There are still some types of crinoids, but it’s the extinct crinoids that crinoid stemswe’ll be talking about here.  If you live in the Midwest, you already know what part of an ancient crinoid looked like because you probably had a pile of crinoid stems crinoid coinssomewhere in your bedroom, and a necklace of threaded crinoid “coins” around your neck in the summertime.  (If you ever hear of or see a necklace or rosary threaded with St. Cuthbert’s beads, you’re looking at crinoids!)  (Sometimes crinoid stems and coins are called Indian Beads, but that’s very misleading, even though some  Native Americans did use crinoid stems and coins to make jewelry.)

If you have access to a lapidary (rock tumbler), crinoids shine up beautifully!  They can be painted, too!

Don’t forget that there are still crinoids in the ocean; they’re echinoderms, like starfish and sea urchins.

The ancient, now-extinct crinoids are seldom found as an intact fossil crinoids- the arms were too fragile and the pieces were scattered by ocean currents.  But the stalk, or stem, can be found, fossilized, all over the Midwest.  In fact, it’s the state fossil of Missouri!

The next time you’re walking by a creek or stream, take off your shoes and wade right in there.  You’ll probably feel the crinoid stems under your feet.  Start a collection.  If you look really closely, you might even find a fossil imprint of an intact crinoid!

You might also find geodes and arrowheads and caddis shells, but that’s another post.

Take a walk outside.  Look around at all the stone.  Imagine what the land where you are standing might have looked like a million years ago.  Everything you see today is here now because of what was there then.

 

Jane GoodwinJane Goodwin is a professor of expository writing at Ivy Tech Community College, a hands-on science teacher for College for Kids, a professional speaker and writer, and a social media liaison  for Steve Spangler Science.  She wanted to be a ballerina and an astronaut, but gravity got the better of her.

The Science Behind Sinkholes

By Blog Editor Susan Wells

Jeff Bush, 36, was killed last Thursday when a sinkhole opened up under his house and engulfed him and his bedroom in Seffner, Florida. Authorities began demolishing the house to get a look at the sinkhole. The house itself was too unstable to enter.

Crews worked carefully to save some of Bush’s belongings while also figuring out how to stabilize and fill the hole, which is estimated to be about 30 feet wide and 60 feet deep. The hole is so unstable that nearby houses are also in danger and have been evacuated.

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How does a sinkhole like this form, especially under a house? How do you know if your house is sitting on top of a potential sinkhole?

We usually see sinkholes on the news when they open up in a roadway and swallow nearby trees or passing cars. Sinkholes, or sinks, mysteriously appear all across the United States, but are mostly found in Florida, Alabama, Kentucky, Missouri, Pennsylvania, Tennessee and Texas. They usually form in areas with soft bedrock or marshy terrains.

Areas where the bedrock is made up of soft minerals and rocks like salt, gypsum, limestone or dolomite are most susceptible. Groundwater running through the rock begins to erode it. Caverns and spaces are created by the eroded rock washing away. The land on top stays intact until the underground space becomes too large, causing the surface to collapse.

Mark Gormus / Richmond Times-Dispatch via AP

Sinkholes usually form where the land does not have good surface drainage. During rains, the water soaks into the ground and stays in the cavern. When the water travels to another location, the land above may not be able to sustain the weight and will collapse.

Humans can also be responsible for sinkholes. Pumping groundwater in construction and development plans may open up weakened areas in the ground. When water is diverted or drainage patterns are changed, sinkholes can also form. If the land is altered, the weight of new material may shift the land and a sinkhole can open up.

For more on sinkholes and facts that could save your life, visit Live Science.

Sources: MSNBC, USGS

The Work of Scientists: Reasons to Read and Write

By Becky Spence – This Reading Mama

Real scientists read the newest research to keep up with the latest trends. Real scientists write their hypotheses, observations, and ultimately their findings in research journals and articles. Real life scientists have real life, authentic reasons to read and write. And as teachers, we can also create authentic reasons for our students to read and write about science!

Just recently, my son (1st grade) and I spent a couple of weeks learning about rocks and minerals. We also spent a significant amount of time reading and writing.

Reading about Rocks & Minerals

We read several rocks and minerals books, not to mention online websites  to learn more about them. I personally love experiment books, like Miguel’s Treasures and picture books like Let’s Go Rock Collecting.  {These were definitely two of his favorites.} Reading nonfiction text spawns curiosity, which leads to more reading in an effort to satisfy the questions. It’s a very cool process. And a scientific one at that!

During our study, we also went to our local science center and perused the rocks and minerals display. He was highly interested in reading the labels beside the minerals and asked LOADS of questions; which lead to more reading when we returned home.

Writing about Rocks & Minerals

We took a little field trip into our own yard and collected all kinds of rocks, digging some out of the ground. We made observations as we collected them such as: This one is smooth. This one is really bumpy. or This rock has shiny parts. He wrote down his initial observations on a Rock Observation Recording Sheet  (free download, several pages included in download).

After scrubbing the rocks with an old toothbrush and drying them off, we got out the magnifying glass and he examined each rock, making more observations. He recorded his observations on the Rock Observation Recording Sheet. We compared our new observations to the initial observations and he wrote about his findings again on the Rock Observation Recording Sheet.

One of the last things we did during our unit study was a rocks and mineral hunt, searching for ways that rocks and minerals were used outside and inside our home. After finding many examples, like this penny, he recorded his findings on this (Rock and Mineral Hunt Recording Sheet) (free download).

The way that reading and writing seamlessly integrate themselves into the learning process is one of my favorite things about literacy. When integrated in this manner, students are typically more willing to read and write because they can clearly see the purpose it serves in satisfying their curiosity to learn. And that, my friend, is the real work of scientists.

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Becky Spence is a homeschooling mama to four little blessings (ages 7, 4, 2, & 8 months). She is passionate about teaching, specifically literacy. She is the author of This Reading Mama, where she shares reading and writing activities as well as free literacy curricula and printables. You can also join This Reading Mama via Facebook, Twitter, or Pinterest.