Backyard Rock Classification

The soil in our yard is filled with rocks. While my husband and I found this frustrating, our sons were overjoyed. During multiple weekends adding landscaping beds to our backyard, the boys occupied themselves picking up rocks from the freshly turned dirt. Being the geeky mother that I am, I seized the opportunity to use my sons’ growing rock collection as an educational activity.

I hit the local library in search of books about rocks, but was discouraged by the overly technical details most contained. The non-fiction available there was WAY beyond my son’s understanding. I did grab Melinda Lilly’s “Read and Do Science: Rocks” book, though. It provided a brief explanation of the three types of rocks (igneous, metamorphic, and sedimentary). I also read "Let's Go Rock Collecting" by Roma Gans to my son before he began sorting, measuring, and studying his own rock collection.

I instructed my son to pick eight rocks of varying shapes, colors, and sizes from his stash. Then I gave him a ruler and a rock classification worksheet I’d made. He wrote the numbers one through eight on sticky notes and we placed each rock on top, to keep them straight.

Download a copy of this worksheet here.

Then one by one my son examined each rock. What color is it? Is it shiny or dull? Rough or smooth? How long is it? Does it look like metal or glass? When he’d made check marks or filled in the appropriate boxes on his chart, we moved the rocks (and sticky notes) around on the table, putting them in order biggest to smallest and wrote the corresponding numbers at the bottom.

I planned this activity to teach my son about observation, but instead the lesson ended up being more about characteristics and measuring. It never occurred to me when I prepped for this, that my son wouldn’t know what shiny and dull meant or how to read a ruler (aside from the big numbers).

So what did I learn from this? That sometimes the best kind of learning is accidental.