This is the third part of our unit on plate tectonics, the rock cycle, earthquakes, and volcanoes. If you want to look at what we studied prior to this, here’s Earth: Part 1 (earth’s layers and plate tectonics) and Earth: Part 2 (the rock cycle).
So now we were nearly up to the part the kids really wanted in the first place, but thankfully they were having so much fun that they sorta forgot that they’d never asked to learn all this other stuff. (Besides, it’s foundational to their understanding the topic at hand!) Since they now knew that earthquakes and volcanoes happen (mostly) at plate boundaries, it was time to study these phenomena in more detail.
We started by reading about earthquakes in a book called Inside Earthquakes (Stewart). Having pre-read this, I knew that it talked about collapsed buildings and roads and the associated fatalities, which would likely be pretty distressing to my kids, so I only read certain selected pages–definitely leaving out the profiles of disastrous earthquakes at the end of the book and sticking mostly to the science.
The Masters of Disaster booklet (I used Level 2, but you can see which works best for you) talked about having an earthquake-safe home, so we looked around our house and talked about what we would do differently if we lived in an earthquake-prone zone. This lesson was reinforced with a quick YouTube trip. This video was great for illustrating what can happen to furniture and other items inside houses, while this video showed how the building itself can be affected by the quake–or not.
To extend the concept, we tried building structures with different materials. One child was given Lego pieces; one child was given cardstock and tape; one child was given toothpicks and marshmallows. (Okay, okay, ALL the children were given marshmallows!) We then earthquake-tested our little houses by placing them on a double-batch of Jello and giving it a good wobble. The Lego house fell right over, but the other two fared better. We talked about why the houses might have performed this way and what sorts of things builders could to to make houses withstand earthquakes better.
Since tsunamis are a related phenomenon mentioned in the Masters of Disaster packet, we tried the included “Making Waves” demonstrations. Since I like to have a video for pretty much anything I’m not sure I can demonstrate adequately, I found two good video options for tsunamis, depending on whether you want to go the whole nine yards (cause, effect, and prevention efforts) or simply stick to the science behind the cause. This TED-Ed video is a good explanation of the phenomenon, but it’s a bit unsettling if you have a sensitive kid (cartoon hands/legs waving in retreating tsunami water, for example). This BBC video uses lab demonstrations rather than cartoons, and it sticks to simply discussing how tsunamis are caused.
So, having talked about plate tectonics and all that goes along with that, we were finally ready to address our original topic: volcanoes. And after all the build-up, I felt like the actual volcano portion of our study was a bit anti-climactic. It still ended with a bang, though, so I’ll definitely share.
For our purposes, I relied heavily on Inside Volcanoes by Melissa Stewart. It has great information on the types of volcanoes, the types of eruptions, and how scientists learn more about volcanoes and put their knowledge to use. We read a few pages at a time, with the kids writing or drawing about any details that interested them as I read.
As ever, I had a video (or two) lined up. This 3-minute PBS clip acts as a good introduction to volcanoes. We didn’t end up having the time to watch all of this 45-minute documentary, but the Ring of Fire video offers a boatload more information.
Finally, for the hands-on portion of this, we needed a way to experience the main types of eruptions. Here are the types we made:
- Shield volcano, Hawaiian eruption: Since shield volcanoes are low and broad, we took a strawberry container, cut a circular hole in the top, nestled a shallow yogurt cup in the hole, and covered the whole business with crinkled brown paper. The yogurt cup held vinegar and red food coloring; when we added baking soda, it formed a watery, gentle eruption that bubbled up and spread over the ground.
- Cinder cone volcano, Strombolian eruption: For this volcano, we used a funnel as our steep-sided volcano. By balancing it halfway off the table, we left space to sneak a squirt gun underneath. This gave us some short bursts of lava. It was supposed to be somewhat sticky, but in order to get the fountain-like spray quality, I just stuck with water.
- Composite volcano, Vulcanian eruption: This one wasn’t lovely, but it worked. Using the top half of a milk carton as our volcano (with a hole in the back for a hand to sneak inside), we rigged it so the top would fall off once we squeezed a tube of thick, red frosting. A quick squeeze generated a violent blast of sticky “lava” which successfully blew off the top of our volcano.
- Plinian eruption: I didn’t even try for a specific volcano type here. A Plinian eruption is a massive, violent blast that completely empties the magma chamber. Can you guess how we simulated this? If you were thinking Diet Coke and Mentos, you’re right on. It sure does produce a dramatic, violent eruption!
The kids love sharing what they’ve learned, so we organized a Learning Party for Daddy and Grandma and Grandpa. I even took a video that we shared with our relatives who live far away! Peatie wrote a report explaining what he’d learned about plate tectonics, Goober wrote a report about her knowledge of the rock cycle, and all three kids had a chance to explain about one volcano type and demonstrate an eruption. To cap off our little party we had sugar cookies that the kids had frosted with tiny volcanoes, and we paired them with a bit of “lava juice”–otherwise known as red Koolaid. (My husband couldn’t fathom why we’d want to both eat and drink sugar, but the kids and I were thrilled!)