Salt is an essential ingredient of an estuary. Basic science ideas about salts (especially NaCl) can effectively be explored by hands-on modelling of crystals of NaCl (table salt). These activities use multiple senses to encode information, and are fun, and conceptually simple.
Forming a crystal
Imagine a solution of NaCl, as the H2O evaporates. With less and less water present, the Na+ and Cl- ions come closer and closer together. Opposites attract, likes repel, so which of the following will (will not) happen?
Either of these possible?
Either of these possible?
As the (possible) trios above crowd together, which of the following will happen?
OR
OR
?
More water evaporates, more Na's and Cl's stick together:
Yet even more water leaves, and these larger clumps stick to each other...
producing crystals of characteristic shape (as seen through a microscope).
