Our fifth Geology lesson with our co-op was all about igneous rocks. As I taught, we put together a poster (I am kicking myself that I forgot to photograph it) so they could better visualize what I was saying. First, we talked about the composition of the earth's crust. Igneous rocks make up the majority. We placed this image in our lapbooks.
Next, we talked about how igneous rocks are formed. The word igneous comes from the Latin word ignis, which means "fire." This was their clue. They immediately guessed volcanoes. I then told them that volcanoes were named after the Roman god of fire, Vulcan. I used this little pocket volcano (bought at Michael's for $2) to demonstrate.
We then talked about how igneous rocks form from volcanoes and the difference between those that are intrusive (formed slowly, below the surface) and extrusive (formed more quickly, on or above the surface). We then looked at samples of each.
First, we hit on a couple of intrusive rocks. Our first was granite. Pink granite (like the sample below) gets its pink color from the mineral presence of lepidolite. This type of rock makes up the inner walls of the Great Pyramids.
After we observed each sample, we added it to our igneous rocks pocket that I printed from https://www.teacherspayteachers.com/Product/Rock-Cycle-Interactive-Notebook-2544056. These went into our lapbooks.
For those samples that I wanted them to add to their pockets that were not provided by the site's download (like diorite), I used this Dover Learning About Rocks sticker book to make slips of paper for them to add that rock's sticker to. They would then add the slips to their pockets with the other samples (see above). (We will use these Dover books to do the same for sedimentary and metamorphic rocks when we learn about those, too. You can purchase these Dover books at http://store.doverpublications.com/0486412911.html for only $1.99 apiece.)
Then it was time to discuss some extrusive igneous rocks. The first we covered was basalt (seen below). As you can see from the picture, the crystals in extrusive rocks are much smaller than those of intrusive. This is because they form more quickly on the surface, cooling and hardening faster than those rocks below the surface. Basalt is the most common rock in the Earth's crust. This is because this rock erupts from deep sea volcanoes and since our planet is covered by more water than land, you can see why this one would be more common on our crust. This rock has also been found on the moon and on Mars.
After observing all of our samples, we finished filling out our igneous rocks pocket then completed this printable (from the same site we printed the pocket) to review.
I also made this sticker for them to add ...
... and printed this image from online. They love decorating their lapbooks with little additions like these.
For homework, I gave them this review sheet I found athttps://www.tes.com/teaching-resource/igneous-rocks-worksheet-6317035. (It's a free download.)
... Gregory Granite ...
... Obadiah Obsidian ...
... and Miss Basil Basalt.
They laughed as I handed out their narratives. I can't wait to see what they return with. Next up? We will do a quick igneous rocks lab to identify mystery rocks (like we did with minerals), then have a field trip to a local park known for its rock structures! Check back with us!