Volcano Activities

We learned about volcanoes (briefly) and did the usual activities. Of course, my kids love volcanoes—who doesn't? We didn't go as in-depth as we sometimes have, but we covered all the basic types of volcanoes and how they are formed. (Above you see a cinder cone…made by blowing sugar into the air with a straw and letting it settle into a cone shape).

My very favorite thing was going to see this IMAX movie about volcanoes. If you ever get a chance to see it, make sure you take the chance! It was so cool! You feel like you are IN a volcano, or walking around one—which I have always wanted to do. And this wasn't even dangerous. :)

Vinegar and baking soda volcano

Rice crispie stratovolcano—alternating layers of cinders and pahoehoe lava (rice crispie mix) and liquid a'a lava (melted chocolate chips).

This must have been a very explosive eruption!

Crystal-Growing Activities

For years now I've been wanting to repeat this activity because it's just SO COOL. But I've also been nervous because it's a little tricky to get right. Sometimes it doesn't work and then you have to patiently boil down the solution and try again. We did need to do that a couple of times, but it was so worth it! 

A couple weird stages our hot ice went through when we overheated it or crystallized it accidentally. It's okay. You can always melt it down, add a little more vinegar, and try again.

Unfortunately, the video tutorial for making hot ice which we watched last time was no longer online, but I kind of remembered what to do, and we watched this video to refresh our memories on the details. I also explain the process in my earlier blog post about it.

Crystals are a great lead-in to talking about the relationship between temperature and pressure (you can also talk about this with respect to geysers). This video is cool, about how a pressure cooker or Instant Pot works. The same principle applies deep inside the earth, and allows water to become superheated or supersaturated with mineral solvents.

Another activity I've always wanted to do is growing a crystal from a seed crystal. It is pretty easy. First, you just grow some small alum crystals, and then pick one of them and suspend it in the supersaturated alum solution. It is all outlined in this tutorial. 

Here are the small alum crystals. They're so pretty--like ice that doesn't melt, or like little diamonds. My children loved playing with them.

We picked out a nice biggish one to serve as our seed crystal. Then we suspended it with fishing line in the alum solution, like this:

We watched it for several days, and it grew a little each day. It was really cool! When we finally took it out of the solution, it was so big and beautiful! Here it is:

We loved the flat faces it developed—like a diamond!

We learned about how crystals grow bigger when left to grow slowly and undisturbed (intrusive vs extrusive mineral growth). Here's an example: we grew salt crystals on two pieces of cardboard (you just soak the cardboard in a supersaturated salt water solution). (See also here.) One was left outside to dry/crystallize in the sun and wind, and one was protected inside a warm oven. You can see the one that grew slower (on the right in this picture) had much bigger crystals! This is like what happens with basalt vs. granite.

Close up of those salt crystals on the right—I love how nicely cubic they are!

And here are some under a microscope. Beautiful!

Looking at crystals under a microscope is such an interesting thing to do. They become even more beautiful when you put a polarizing filter over your eyepiece so you can see the colors (birefringence). You can learn more about this and find instructions here.

These are citric acid crystals

Epsom salt crystals

And sugar crystals.

Epsom salt crystals, not under the microscope. You can learn how to grow these here or here. They grow really fast!

Another example of "intrusive" and "extrusive" crystal growth, this time with sugar. Instructions for this experiment are here, and you can learn more about the process in geology here. 

Here is the hot sugar solution while it's still cooling—you can see the surface has cooled more quickly than what's underneath, forming these cool surface wrinkles. Sometimes pahoehoe lava has wrinkles like this too!

And here we have the smoother, small extrusive crystals on the left, and the bigger intrusive ones on the right.

You can also make melted sugar that cools so quickly, it doesn't have time to form crystals at all! This is similar to obsidian. You can learn how to do that here. It is so pretty! And the children love to break off pieces and eat it. :)

Crystals are so cool. Find more crystal-growing activities here!

Landforms, Glaciers, and Erosion

We were lucky this year because we got to take the best Geology Field Trip ever—to the Canadian Rockies! We went to Banff and Jasper National Parks. It was amazing! You can read more about our trip here, but I'm including a few pictures of the mountains and glaciers we saw.

Below, you can read about a few activities we did to learn about these principles when we got back from our trip.

These glaciers were amazing to see! I love the blue tones of the ice as it gets thicker.

This is Athabasca Glacier—you can walk right up onto this one.

Gorgeous turquoise glacial lake

Perfect example of a glacial U-shaped valley!

One day we made play-dough (this is my favorite recipe) and the children made all the different kinds of landforms we'd been learning about: mountains, glaciers, moraines, volcanoes, and so forth.

A cave!

Fold mountain

A volcanic mountain range (from a hot spot). And I think there are some hoodoos in there too.

Teddy, very serious about his fold mountain…

and his sinkhole!

Fault-block and tectonic plate collision mountains

While in Canada, we stayed at a house by a river and found some beautiful river rocks.

They were already so smooth and flat and pretty! We collected a few…

And took them home to polish in our rock tumbler!

Didn't they turn out beautifully?

Another fun way to make landforms in with sand in a cake pan—then you pour water in to make deltas, rivers, lakes, etc. More pictures and ideas here.

Another activity we did was making some big blocks of ice and then experimenting with them on a nearby hill. We learned about glacial till, terminal and lateral moraines, cirques, glacial striations, etc. And, we had fun sliding down the hill on our ice blocks! :)

You can find more glacier activities here. And even more here.