This project guides you through the process of growing salt crystals from a supersaturated salt solution. It's a visually rewarding experiment that demonstrates how molecules arrange themselves into ordered, repeating patterns.
If a supersaturated salt solution is allowed to cool and evaporate slowly, then salt crystals will form as the water evaporates and the salt molecules arrange themselves into a crystal lattice structure.
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Tie one end of the string to the middle of the pencil and the other end to the paper clip.
Rest the pencil across the top of the jar so that the paper clip hangs down into the middle of the jar without touching the sides or bottom.
With adult help, heat the water in the saucepan until it is boiling.
Turn off the heat and slowly stir in the salt, a little at a time, until no more salt will dissolve. This creates a supersaturated solution.
Carefully pour the hot salt solution into the jar.
Place the jar in a location where it will not be disturbed.
Observe the jar every day and record the growth of the crystals on the string.
After a week, carefully remove the string from the jar and examine your salt crystals.
As the water in the solution slowly evaporates, the salt concentration will increase, and salt crystals will begin to form on the string and the sides of the jar. The crystals will grow larger over time, forming cubic shapes characteristic of sodium chloride.
The slow evaporation of water from a supersaturated salt solution.
The formation and growth of salt crystals.
The type of salt used, the amount of water, and the temperature of the environment.
An adult should handle the boiling water. Be careful when pouring the hot solution. Do not eat the crystals.
Display your best crystal formation, perhaps in a small jewelry box.
Use a magnifying glass to allow judges to see the cubic shape of the crystals up close.
Create a time-lapse video or a series of photos showing the crystals growing over the week.
