Homemade Christmas tree
How to decorate a Christmas tree using salt
For those who want to feel the spirit of Christmas every day!
Perform this experiment only under adult supervision.
- 3 tsp table salt;
- 3 tsp yellow prussiate of potash solution;
- liquid soap;
- boiling water;
- paper Christmas tree;
- Petri dish or saucer.
Pour 3 tsp of table salt into a glass. Add 3 tsp 0.3M solution of yellow prussiate of potash. Add some boiling water. Stir. Pour the resulting mixture into a Petri dish or saucer and add a few drops of liquid soap. Place a paper Christmas tree in the center of the container. It’s important that the paper be of the right consistency to absorb water well without deforming. Wait 12 hours. Do not move or jostle the Christmas tree while the crystals are growing. After 12 hours, the Christmas tree will be covered in "snow!”
The hot solution we poured into the Petri dish contains a lot of dissolved sodium chloride NaCl. Actually, it contains a greater quantity of salt than room-temperature water can hold. Consequently, when the system cools, the sodium chloride precipitates out of the solution in the form of tiny, fluffy crystals. These crystals appear on the tree thanks to the capillary effect. First, the solution soaks through practically the entirety of the paper tree. Then, as the water gradually evaporates from the surface of the paper, the salt gradually settles on it. But how did we obtain such fluffy salt crystals? Salt crystals are usually cubic, right? This is mostly due to the addition of potassium hexacyanoferrate and the way the crystals form on the paper tree. A similar experiment is included in the “Chemistry of Christmas” set from the MEL Chemistry subscription.