Salt Iron Sand Separation
During high school chemistry, students in my class were tasked with separating a mixture of materials using any information that we could find in researching them. I was very excited when we received bags containing the mixture because I knew exactly what I would do to separate them right when my teacher told us what the materials were, which was sand, iron and salt.
I knew that salt was easy to dissolve in water while sand was not, and in the short-term iron was not either, and I knew that iron was magnetic while neither sand nor salt was. Using my many available magnets wrapped within a plastic bag, I went over the mixture repeatedly to remove as many iron filings as possible. Once I got out as much as I thought was feasible, I poured water into the mixture and dissolved all of the salt. I was then able to easily filter out the sand, which mostly just stuck to the container as the saltwater poured out.
I noticed that the saltwater was a dark color, so before evaporating the water, I dipped my magnets into it, still covered in a bag, and quickly noticed a change in its opacity. The microscopic iron filings that remained in the water were pulled from the liquid solution and attached to the bag, leaving a mostly clear liquid behind. I then brought the mixture to the stove and boiled off the water in a steel can, leaving behind salt crystals which I was able to scrape out and into a bag.
I collected the three materials in separate bags and labeled them, thoroughly satisfied with how clearly discernable the three now were from each other when compared to how they began. This was one of my favorite assignments in high school and I’m glad that it is a part of my school’s chemistry curriculum, as it teaches students in an engaging way to think critically about the tools available to them and do some simple research and tools available at home to do something that would normally seem difficult with little effort.