In order to learn about a new unit on different properties of mixtures, Andrew led a class experiment on making, "magic sand." Sand that doesn't get wet like normal sand does. To start the experiment, my table group and I poured pink reptile sand in the bottom of a large black tray. Once all the other groups had finished this task, we all went out side and sprayed our sand with 5 layers of silicone spray, which would make the sand waterproof, we mixed up the sand in-between each spray. It took a while for everyones sand to dry, but when they were all ready we went inside to test the efficiency of our waterproof sand. We filled beakers of water and added small amounts of sand into it. Instead of mixing with the water, the sand globbed up into little clumps. Each clump appeared to be waterproof and this was confirmed when we lifted the sand out of the water and it collapsed into its usual grainy form, except it was totally dry!
Before spraying the sand we went through a lesson on ionic and covalent compounds. Ionic compounds form between metals and non metals. They're held together by strong ionic bonds. In ionic bonds, positively charged ions are called cations, negatively charged ones are called anions. These two kinds of ions come together to form ionic bonds, where they transfer electrons among themselves. Covalent don't need metals to form, they do so between nonmetals, here, electrons are shared instead of being transferred.
Two terms that heavily applied to this experiment are hydrophilic and hydrophobic.
Hydrophilic substances dissolve in water and are ionic as opposed to hydrophobic substances that don't dissolve in water.
How does this apply to the experiment? The unsprayed sand we began with was hydrophilic, it would have gotten wet if we had exposed it to water. When we used the silicone spray, thanks to it's waterproof coating properties, the sand became hydrophobic, and also became a covalent compound.
I thought this lab was interesting because I didn't expect a noticeable difference in the sand, I thought it would just get darker and feel wet, but the sands relationship with water after the silicone spray was very different than just a little less moisture.
Below are some images from my group's process.
Before spraying the sand we went through a lesson on ionic and covalent compounds. Ionic compounds form between metals and non metals. They're held together by strong ionic bonds. In ionic bonds, positively charged ions are called cations, negatively charged ones are called anions. These two kinds of ions come together to form ionic bonds, where they transfer electrons among themselves. Covalent don't need metals to form, they do so between nonmetals, here, electrons are shared instead of being transferred.
Two terms that heavily applied to this experiment are hydrophilic and hydrophobic.
Hydrophilic substances dissolve in water and are ionic as opposed to hydrophobic substances that don't dissolve in water.
How does this apply to the experiment? The unsprayed sand we began with was hydrophilic, it would have gotten wet if we had exposed it to water. When we used the silicone spray, thanks to it's waterproof coating properties, the sand became hydrophobic, and also became a covalent compound.
I thought this lab was interesting because I didn't expect a noticeable difference in the sand, I thought it would just get darker and feel wet, but the sands relationship with water after the silicone spray was very different than just a little less moisture.
Below are some images from my group's process.