Grow crystals? Yes you can and it is so easy!
We just completed a whole series of classes on snow and ice and we grew crystal snowflakes at the preschool as part of our study. This is a fun way to incorporate a bit of science into the day, fun because it is like magic! Here are complete instructions for a lesson plan at school or some scientific magic at home!
Keeping the discussion really light with the kids, we touched upon states of matter and chemical reactions by doing an experiment in a cup. For this class I gave each child a popsicle stick and a clear plastic cup filled about a quarter with warm water. I poured in a small amount of salt and asked them to stir it around. We used our scientist eyes and observed what happened in our cups. When I asked them what they saw they looked up at me with curious excitement and we talked about what happened to the salt.
The children's answers as usual were preciously insightful ~
"It is swirling."
"The water is white."
"It mixed in."
"It is gone!"
"Well, where did it go?" I asked and they didn't know. So I told them that it had dissolved. That the water liked the salt so much that the water picked the salt right up and is now holding onto the salt so tight that we can't see it anymore.
Then we tried mixing in a lot of salt. We mixed salt into the water until the water could not hold any more salt. In other words, the salt would no longer dissolve. This is called a saturated solution.
The kids, looking into their cups, wondered why the salt wouldn't dissolve anymore? "Because the water is full of salt, it can't hold anymore salt. It is like the water's arms are full."
This is what we need the water and salt to do for growing our crystals. Because when we put our chenille snowflakes into the saturated water solution the salt will grab onto the snowflake and grow a crystal.
Tip ~ Have the kids empty their cups into a cooking pot. Save this pot to use later. Then collect the popsicle sticks and cups and keep them handy for the next part of your experiment.
Next we made snowflakes out of chenille stems. From a large pile of assorted chenille stems the kids each picked their favorite. We had everything from white to black to yellow to red. Interesting for snowflakes!
Tip ~ We formed the chenille stems into a snowflake shape by cutting each chenille stem into 3 pieces. Make sure one of the pieces is longer than the others so you can use that piece to hang the snowflake from a popsicle stick. Twirl the pieces together in the center to form the flake.
Then I had the kids put a few beads on their snowflake to make it extra special. I attached their snowflake to one of the popsicle sticks from our above experiment and hung it over the rim of one of our cups.
Tip ~ Have a sharpie handy to label the popsicle sticks as the children finish decorating their snowflakes. This way the snowflakes will be labeled and ready to go home when you are done growing the crystals. I labeled their cups and was sad later to have to re-label the sticks!
Finally, I took some time without the children to heat water to almost boiling and then I dissolved borax power into the water stirring until, you guessed it, no more borax would dissolve. Salt works too. You can use it to grow the crystals instead of borax but the borax is faster at producing results. Because borax, even though it is completely natural, is dangerous if swallowed I didn't want to use the borax for our hands-on experiment with the children. But it was perfect for growing the snowflakes!
Tip ~ Use the pot you had the children empty their cups into earlier to heat the water. You can even just add more water to the salt water already in the pot and then add borax. That is what I did and it turned out fine.
Our snowflakes came out great! We had plenty "ooh's" and "ahh's" as we pulled each snowflake out of solution.
More Please ~ Check out other fun ice and snow experiments...