As part of our studies of STRUCTURES in my 2nd grade GT class, we learned about the largest living structure on Earth: the Great Barrier Reef.
One of the students’ favorite projects was creating their own “coral reefs.” Students grew crystals in their own containers,, coloring them to look like the coral in the GBF.
I regret that so many wonderful resources we used in this unit study have disappeared from the internet, but if you’d like to try this hands-on experiment, I can share how we used this RECIPE to create our coral landscapes.
WHAT I DID in advance:
I purchased regular kitchen sponges, and small plastic containers from a dollar store. You could have students bring in their own or have parents donate them. I did NOT use ammonia. I cut up the sponges into smaller pieces, a little larger than dice or number cubes (see photo below). You could have your students do the cutting, but I felt it would take too much time.
I also borrowed 4-5 measuring spoons (tablespoons), table salt, food coloring, a water pitcher (optional), and small paper cups (also optional) from our science room.
I found Mrs. Stewart’s Bluing at a local store, but you can also order it. I was able to use money in my budget for this. You will need at least 1/4 cup per student.
WHAT WE DID in class:
I set up a station at a back table in my room and called students a few at a time to make their reefs.
- Students wrote their names on mailing labels and put them on their containers.
- Next, they placed sponge pieces in their containers in any arrangement they chose, as long as the sponges were not too close to the rim.
- I poured water into a paper cup for each student so that the cup could be held over the container as students measured out one tablespoon of water at a time and poured it over the sponge pieces.
- Students measured out table salt, one tablespoon at a time, sprinkling it over the base material.
- I measured and poured the liquid bluing into each student’s container.
- Students then took their containers to the shelf and moved to their next activity.
WHAT I DID over the next few days:
Because I wouldn’t see my second graders in class for another week, I completed the steps for Days 2 and 3. It only took a few minutes to add what was prescribed for each day since the containers were all lined up on the shelf.
I wanted the students to create the colors, so I arranged for a few at a time to visit me during lunch or my conference period. The students added a few drops of food coloring (using several colors) to their crystals.
By Day 3, coral-looking structures began to appear, and one week later, students were thrilled to see their “coral reefs.” Rather than discuss the science behind this activity, we discussed how our coral reefs were alike and different from real coral structures. Students came up with some of these ideas:
- Our “coral reefs” are made up of salt crystals, not tiny living animals.
- Our “reefs” are models and human-made, not natural structures.
- Our structures are not to be eaten, but coral in reefs provides food for many ocean creatures.
- Nothing is hiding in our structures, but many ocean creatures hide and seek shelter within coral reefs.
- Our structures are ALIKE in that they both GROW!
- Our structures are ALIKE in that they both are “stuck” where they grow!
There are many great resources for teaching about the Great Barrier Reef and fabulous videos for kids.
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