I recently began working as a long-term sub in a 6th grade science classroom. I inherited 5 classes of students who hadn’t had a consistent teacher in well over a month. Understandably so, many of the students seemed less than invested in learning about science. My immediate goal was to work on establishing positive relationships with the students and to reassure them that I would be with them until the end of the school year. I hoped that with a bit of stability and support, they would come around and understand that they can still become invested and excited about our science class.
Next, I set about figuring out how I could make the content engaging in order to capture the students’ interests and motivate them to spend the rest of the school year being jazzed about science. I was less than thrilled to learn that the unit I would be responsible for teaching was… rocks. In the words of one of my students, “What is fun about rocks?!”
As it turns out, I have had a certain degree of success in making rocks and minerals a captivating topic! For one lesson, I started off by telling my students that something very serious had happened over the weekend. With a somber voice, I told them how there was a celebrity gala at the American Museum of Natural History, and during this event, one of the invaluable minerals had been stolen and replaced with a fake! I shared with them how museum personnel and police alike were baffled because when they went to check the security footage to figure out what happened, they realized that the footage had been wiped blank. So, it was up to them to analyze the minerals at the museum to figure out which one was fake. They had to research mineral qualities like hardness, streak, luster, and density and compare these characteristics to the specimens at the museum to determine which was fake. My favorite part of the whole activity was the students’ uncertainty about whether or not the museum heist had actually happened. (Sixth graders, I’ve found, are adorably gullible.)
My main purpose for this post, though, is to share with you an activity I developed to give the students hands-on, intriguing ways to learn about minerals. One of the main things they needed to know about minerals was that they grow in a crystal formation. While the crystals that we grew weren’t true crystals in the scientific sense, it was my hope that this experience would help solidify for them the idea that minerals grow as crystals. Plus, it was a fun way to get them excited about science!
Growing Crystal Gardens
I got a lot of information for conducting this activity from The Owl Teacher on Pinterest. I bought a few car wash sponges (kitchen sponges have soap in them and makeup sponges have antibiotics, so car wash sponges are said to work best!) I had my students cut up the sponges into small cubes and put them into their little cups. They then sprinkled Kosher salt over their sponges and added food coloring to make their crystals grow in a fun variety of colors. I went back later and added the key ingredient, an ammonia and bluing agent mix, and viola- we had some beautiful crystals! Now, the students check on their crystals every day to see their progress, and I see an enthusiasm and pride in them that was not present when I first started as their sub. If I had more foresight, I would have had them take pictures with their iPads of the sponges with the salt on them and then periodically in the future as the crystals were growing. We could have practiced the scientific practices of making careful observations and documenting change. (Oh well, maybe I’ll get to do this if I ever teach a rocks and minerals unit in the future. For now, though, it was worth it for me to simply see the kiddos’ excitement at their colorful creations!)
Some photos of our crystals after 1 week:
How to do it:
- Car-washing sponges
- Small, condiment cups
- Food coloring
- Kosher salt
- Bluing agent
- Popsicle sticks
- Have students cut the car wash sponges with scissors into small cubes
- Students should collect one condiment cup and one sponge cube. Have them place the sponge inside the cup.
- Instruct students to write their names on the cup.
- Mix 1 part ammonia with 1 part bluing agent. (It is super stinky and these chemicals are harsh, so I did this myself instead of having my students do this.)
- Pour the ammonia-bluing agent mixture over the students’ sponges, adding enough for the liquid to coat the bottom of the cup.
- Have the students take a Popsicle stick and press down on the sponge so that it soaks up more of the mixture.
- Students sprinkle Kosher salt in a thin layer over the top of their sponges.
- Have the students add no more than 3 drops of food coloring on top of the salt layer.
- Place cups in an area where they will be visible but won’t be disturbed. The crystals, when they form, will be very delicate. Our crystals crumbled into dust as soon as we touched them, so make sure the students are very careful when they observe the crystals!