Crystalline experiments

There have been wonderful scenes of unrestrained curiosity this past week, all related to crystals. To begin with, salt forms crystals, and last week the children got to examine salt crystals through magnifying glasses. We had two types of salt crystals, sea salt and Himalayan pink salt (both bought at Trader Joe's), and after the children had observed them at their desks for a few minutes, I mentioned that if anyone wanted to undertake an experiment using regular school materials, I'd be glad to help... That was all the input I gave. What followed was a burst of classroom-wide creative curiosity that was entirely student driven! Some of the experiments that have been completed (or are still underway) include—but are not limited to—:

— testing the properties of salt as an antifreeze, by placing two cups of water, one salted and one fresh, in the freezer

— sprinkling the two kinds of salt on different ice cubes, to see which cube would melt first

— dissolving the salts together in a pot, and letting the water evaporate, to see if the two salts would be combined or separate in the residue, and to see what form (separate crystals? a solid lump?) that residue would take

— taste-testing salt water to see if the two salts could be reliably distinguished by taste

— placing large salt crystals in a cup of water, without stirring, to see what would happen

— testing to see which type of salt dissolved faster

— finding out whether warm or cold water dissolves salt faster

As to other types of crystals: the beginning of our salt theme coincided with the first snow of the year. We've taken the magnifying glasses outside, examining and drawing snowflakes on different days and at different temperatures. I've heard exclamations from all around the playground: "Oh I found a really good snowflake, come look at this!" "I think they're made up of tiny crystals, in strings..." "This snow is totally different from yesterday! It's like balls instead of snowflakes... almost more like ice than snow."

And yesterday, I got called over to the sandbox at recess to examine a piece of sod with ice crystals hanging below it. It is absolutely wonderful being around these observant, curious children.